The Tropical Fruit Forum
Citrus => Citrus General Discussion => Topic started by: Millet on January 16, 2018, 12:46:20 PM
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Winter prebloom foliar spray application of low Biuret urea is known to greatly increase flower number, thus greater crop yield. Proper timing is important to achieve the desired outcome. Winter prebloom sprays are designed to increase flower number and fruit yield without reducing fruit size. Winter prebloom foliar sprays with low biuret urea (46-0-0 <0.5% biuret) is applied at the rate of .44-lbs. (200-grams) in 2 gallon of water plus one teaspoon of a good surfactant per gallon.. For large area sprays (acres) 50-lbs. per 225 gallons water. NOTE: a second low biuret urea foliar spray should also be done after early fruit drop and June drop periods to insure an increase in fruit size. In most areas this would be around July 1 to July 20.
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Hello my friend, thank you for your post. Most of my citrus trees are full of flowers but a bit yellow since summer dry period so i will do it in next days! Thank's. ;D
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Luisport, I'm not sure about the blooming period in your area, However, in the future make your low biuret foliar spray about 1 to 2 months prior to the expected bloom date.
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A friend has a Gold Nugget Mandarin on Flying Dragon. It was purchased as a "5-gallon" tree and has been in the ground for three years. It's still really small. Would the .44-lbs. per 2 gallons of water (actually a gallon or less would probably suffice) mixture be recommended for this tree?
Thanks
gary
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Waiting, nitrogen is one of the most use elements for a citrus tree. Of all fertilizer nutrients used as a foliar spray on citrus, urea is the most readily accepted nutrient by the tree. Urea absorbs into the tree through the leaves faster that any other element. It most certainly would help the tree to get going. Just be sure the urea you apply is low biuret. 100 grams/ 1-gallon, spray to good coverage, but do not over due it. Spray earlier in the morning or in the evening. Do not spray a citrus tree during the heat of he day.
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Thanks, Millet. Looks like a shopping trip is in order :-)
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Luisport, I'm not sure about the blooming period in your area, However, in the future make your low biuret foliar spray about 1 to 2 months prior to the expected bloom date.
Well the weather is changing here. Now we have the first rains in November with warm temperatures. This makes all citrus to puch flower buds, but we didn't got so much freeze temp so they didn't got killed. Now the flower buds are one or two weeks to bloom. It will be a great citrus production this year.
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What do you call low biuret in urea?
The urea I have access to has 1% biuret. Is that high, low or mid range for urea ?
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Low Biuret urea is defined as 0.5% biuret or lower.
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Thanks
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Nice info!
Are all 46% Urea fertilizer low biuret or there is no correlation?
Cause I only found 1 product labeled as low biuret.
Another thing. I read this help with cold temps, but Urea is mostly Nitrogen while just yesterday I saw a video saying applying PK fertilizers helps with cold, so which one is the correct one?
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Millet,
Low biuret urea is "46-0-0 <0.5% biuret", not "46-0-0 >0.5% biuret" ;D
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Is anyone able to say what effect/s using urea biuret of 1% would have on citrus? Not that I am using it, just curious
Mick
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Millet, what surfactant do you recommend?
I have some trees in a greenhouse that have not yet flowered, others are in various stages of lowering. Is it too late to apply urea to trees that are already flowering?
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I don't have a scale that will weigh small amounts. Can someone guesstimate how much 100 grams would be in cups or tablespoons?
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Ilya11, the absolute correct description of low biuret Urea would be (46-0-0 =or less than 0.5% biuret) or (46-0-0 =>0.5% biuret). Vlad the surfactant I use is Tween-20 which is also a food grade surfactant.
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Slicko, citrus is more sensitive than most crops to biuret, an impurity present in urea fertilizer created by excessive heating of chemical reactants during urea manufacture. Toxicity can result from soil or foliar spray applications of urea applications with elevated biuret concentration. If urea is used as a nitrogen source for citrus, it should contain not more than 0.25 - 0.50% biuret by weight. The leaf symptoms of biuret toxicity appear as an irregular butter yellow chlorosis that starts at the leaf tip. Young leaves are more vulnerable than old ones, and affected leaves do not regreen. On very young, expanding leaves, urea with a biuret concentration in excess of 1.0% may cause distortion as well as typical yellowing. Succeeding growth flushes appear normal, provided applications of High biuret urea is not repeated.
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Vlad, if your trees are already in flower it will not help to increase additional flowering. Urea must be applied prior to the time of irreversible commitment to flowering. After the tree has already committed to flowering it is to late. However, applying low biuret urea at most any time during the growing season will always be beneficial as a nutrient ingredient.
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A 16oz bottle of Hi-Yield brand spreader/sticker runs about $7 at Walmart.
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Waiting, does your friend with the Gold Nugget Mandarin regularly fertilize his tree? For in ground citrus trees a 1 year old tree should be fertilized 6 times per growing season, A 2 year old tree 5 times per growing season. A 3 year old tree 4 times, and trees 4 years old and older 3 times per growing season.
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Thanks Millet for your information. Understanding the problem means that you are well on the way to solving it.
Mick
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I don't think the tree has been fertilized unless indirectly from when they fertilized tomatoes growing in the same planting bed. I'm going to try to get them on a schedule but they don't take well to instruction. Last year he pruned off all of the small wood on his peach tree despite my explaining how to do it (I wasn't there at the time) - didn't have a single peach.
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Waiting, for your neighbor's tree ....... no fertilizing = no growth.
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Can anyone name a specific name brand product name that meets the low biuret requirement?
Thanks
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You can find it on the Internet ----- type in Low Biuret Urea
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Interesting thread...so do you suggest feeding with urea to all citrus Millet? ....I have been feeding my trees with something called B green...its a slow release organic feed high in carbon.......then compost on top of that in the garden....i just use the b green for the pots and mulch........I also water with worm juice every now and then...........u still suggest the 5-1-3 npk for pots millet?
I was always confused whether ammonium or urea was better for citrus.....I am a bit concerned spraying urea based soluble fert when its so evil hot over here.........My eureka lemons never look happy here! ....have one big one in ground and one in pot and both have pale leaves and brown crinkle effect.........the big one in ground has never flowered.
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Laidback nice hearing from you again. As for spraying urea to obtain a better fruit crop, that advice was for growers in the northern hemisphere. You are in the southern hemisphere, so you should spray your trees 1 to 2 months prior to your tree's expected bloom date.
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Thanks Millet...I have citrus that flower and fruit at different times..........some interesting varities
= cara cara orange/pineapple/ washington navel/ arnold blood orange/comquat cammolidon(something like that !)/emperor mandarin/imperial mandarin/hickson mandarin/daisy mandarin/Nules clementine/kaffir lime/tahitian lime/indian lime/lemonade/meyer lemon/eureka lemon/japanese seedless mandarin/honey murcott mandarin/late navel orange..........only the pineapple and comquats(caloomidium) are in flower at the moment.........the lemonade /pineapple(actually tastes like pineapple)and lots of lemons( a dwarf meyer variety) have big fruits on them.....so i think some might flower soon........they are all putting out new growth.
By the way.....Your "hero" status is justified !!!!! :D
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Amazon carries urea from Alpha Chemicals. I looked at their website and it says "maximum biuret = .5%". The price at Alpha Chemicals website is considerably cheaper but shipping costs might tip it in favor of buying through Amazon. 1, 5, and 10 pounds ships free if your combined Amazon-shipped items exceed $25.
I'm not crazy about Amazon's dominance of the retail sphere but often it is the best (or at least most convenient) option.
https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=Urea%2BAlpha%2BChemicals (https://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=Urea%2BAlpha%2BChemicals)
http://alphachemicals.com/urea (http://alphachemicals.com/urea)
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Millet, for in ground citrus (not potted/containers) how would a 10: 1 dilution of human urine work at the root zone for pre-bloom feeding?
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Is it safe to use Hi-Yield brand spreader/sticker with Neem oil?
Will it act as an emulsifier of the oil?
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Pineislander, Human urine, is not urea. Ninety percent of the nitrogen content in human urine is present as ammoniacal N type, with ammonium bicarbonate being the dominant compound.
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Not true, nitrogen in human urine is mainly urea
https://www.thoughtco.com/the-chemical-composition-of-urine-603883 (https://www.thoughtco.com/the-chemical-composition-of-urine-603883)
But urine contains an excess of NaCl that can be toxic to plants.
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Pineislander, Human urine, is not urea. Ninety percent of the nitrogen content in human urine is present as ammoniacal N type, with ammonium bicarbonate being the dominant compound.
Millet, if you were using this paper as reference, they were looking at a specific type of liquid from a toilet which separates urine from feces. The effluent does include flushing water and was collected from a septic tank which had been stored for months. That could be the reason why the urea/ nitrogen was different, but I'm not sure. They do say:
Nitrogen composition
Total nitrogen concentrations varied between 1.79 and
22.61 g L -1 of which 95% was present as ammoniacal
nitrogen (Table 2). The high pH values of 8.9 result in
ca 30% of the ammoniacal N being present as dissolved
ammonia. However, no urea or uric acid was detected
in any of the samples, indicating that complete decomposition
had occurred since excretion.
https://link.springer.com/article/10.1007/BF00750100
The goal is to maintain sufficient nitrogen to the trees, correct?
I am wondering if it matters how the tree is supplied?
Is it better to use a purchased foliar amendment or to use something we usually dispose of as waste?
I am a self-reliant penny-pincher.
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Pineislnder its your tree do as you wish.
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Foliar sprays can enter into the leaf only as long as the foliar spray remains in the liquid state. Once it drys, it can no longer be absorbed by the tree. When urea is used the situation is a little different. Urea is highly hygroscopic. Hygroscopic is the ability of a substance to absorb moisture/water from its surroundings; because of this effect, after urea is sprayed on the foliage, and eventually dries, it re-hydrates into a usable nutrient as the humidity rises. Therefore, because of this property it is a valuable additive to add a small amount of urea to other foliar sprays such as a trace mineral spray, because it will re-moisturize the spray, making foliar sprays much more nutrient efficient.
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Foliar sprays can enter into the leaf only as long as the foliar spray remains in the liquid state. Once it drys, it can no longer be absorbed by the tree. When urea is used the situation is a little different. Urea is highly hygroscopic. Hygroscopic is the ability of a substance to absorb or adsorb moisture/water from its surroundings; because of this effect, after urea is sprayed on the foliage, and eventually dries, it re-hydrates into a usable nutrient as the humidity rises. Therefore, because of this property it is a valuable additive to add a small amount of urea to other foliar sprays such as a trace mineral spray, because it will re-moisturize the spray, making foliar sprays much more nutrient efficient.
If you are doing foliar low biuret N you might want to look into the newer urea triazone products. Supposed to be better than old fashioned urea with less salts, more soluble N and a better carrier for micros.
N-sure and Triamin
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After delving further into Hi-Yield Spreader Sticker in order to answer the question I've come to the conclusion that it shouldn't be used. It consists of alcohol ethoxylate and alkylphenol ethoxylate. Alcohol ethoxylate appears to be surfactant only while alkylphenol ethoxylate does have emulsifying properties. Alcohol ethoxylate appears to be safe, however alkylphenol ethoxylate is an xenoestrogen (it acts as an estrogen). It's been proven to cause the feminization of aquatic organisms and decrease male fertility in those organisms. There are predictions that most men in North America, Europe, Australia, and New Zealand will be infertile by 2060 and I have to wonder if ths is a contributing factor.
Bonide brand spreader/sticker, which contains the same ingredients, is listed as "not for sale in California". Of course, that could just be because they refuse to pay the fees California demands for certification.
Southern Ag spreader/sticker contains octyl phenol polyethoxy ethanol, a known carcinogen, and also contains isopropanol, rubbing alcohol. Monterey "spray helper" is mostly cotton seed oil but also contains the above mentioned xenoestrogen, at 17%, and isopropanol.
I could find little to suggest that Tween 20 (Polysorbate 20), suggested by Millet, is harmful. Polysorbate 20 and Polysorbate 80 are the same base chemocal, polyethoxylated sorbitan. The difference being lauric acid.added to Polysorbate 20, and oleic acid added to Polysorbate 80. Polysorbate 80 is not known to be carcinogenic, but studies have found decrease fertility in rats at very high rates of ingestion. The key being "very high rates". So, Tween 20 appears to be the safest option.
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In the outstanding text book "Advances in Citrus Nutrition", Tween-20, a food grade surfactant, was in all studies found to be the best surfactant for citrus tree applications.
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Millet, thanks for the reminder. I sprayed my 2 Arctic Frost today. I mixed up 1 quart of the Urea solution (25 grams/quart)
I applied the solution to both sides of the leaves.
This is a make or break year for this variety for me.
Hopefully this will make a difference.
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For those that have already sprayed their trees with low biuret urea to set a larger fruit set in the coming crop, now there are several more sprays needed to insure that the fruits will be good FRUIT SIZE and the finest quality. The amount of building materials, energy and hormones that are available to the developing fruit controls fruit size. When the tree sets a heavy crop, the fruit's size will be reduced if there is an insufficient amount of any one of these factors. Summer applications of low biuret urea (46-0-0 > 0.5%. biuret) applied after the completion of EARLY FRUIT DROP, and then another spray after most of "JUNE" drop will increase fruit size without affecting total yield. Timing of the applications are important. The treatments increase fruit size by extending the cell division stage. The end of cell division is characterized by maximum peel thickness. In California the "June" drop sprays should be made between July 1 and July 15th. All applications should be made to give good canopy coverage, much like applying a pesticide. All applications of low biuret urea should be made when the air temperature is below 80-F, early morning or late afternoon to early evening. The urea spray already completed, plus the spraying at early fruit drop, and June drop will give a larger crop, with fruit of nice size and high quality. (Crop Production Manual).
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Slicko, citrus is more sensitive than most crops to biuret, an impurity present in urea fertilizer created by excessive heating of chemical reactants during urea manufacture. Toxicity can result from soil or foliar spray applications of urea applications with elevated biuret concentration. If urea is used as a nitrogen source for citrus, it should contain not more than 0.25 - 0.50% biuret by weight. The leaf symptoms of biuret toxicity appear as an irregular butter yellow chlorosis that starts at the leaf tip. Young leaves are more vulnerable than old ones, and affected leaves do not regreen. On very young, expanding leaves, urea with a biuret concentration in excess of 1.0% may cause distortion as well as typical yellowing. Succeeding growth flushes appear normal, provided applications of High biuret urea is not repeated.
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Tween 20 food grade, what brand do you use Millet and where do you order this. Amazon has a product called: polisorbanate 20 made by a florida company.
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Luak, Tween-20 is a trade name. The chemical name is Polysorbat-20. Polysorbat-20 is the very same chemical.
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Thank you for your informative post. it's great for newbie like me.
quick questions: do you spray on leaves? and do you use 1 or 2 gallon sprayer from Homedepot?
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Going to try a foliar spray on my in ground citrus and avocados this year. It is an organic product called Acadian derived from seaweed, analysis is 0.1-0.0-5.0. I had to buy 2.5 gallons and it was pretty expensive, looks like soy sauce. The dose is quite dilute so I have my doubts on how effective it will be but why not. I am going to use about 4oz. in about 4 gallons of water for approximately 40 trees. Just tried it out on a handful of trees to make sure there are no adverse effects and then I will apply the rest. I did not use a surfactant, as my fertilizer supplier said it was not necessary. Looks like they recommend every 2-4 weeks through the growing season. Will report back if anything interesting happens.
I am also using an organic dry fertilizer now, the stuff looks and smells like rabbit food. It is from True Organic Products with a 10-2-8 analysis.
Those two combined with yards and yards of mulch will hopefully give me a solid organic solution to my fertilizing needs.
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Oh boy, i got 20lbs by accident from Amazon for only 1 cocktail tree. It will last me forever.
.44 lb ~ approximate 11 table spoon. Someone may need to double check it.
Question because someone said dont over due it. So for 2 gallons mixed, how big is the tree?
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Be careful, biuret is forming from urea during storage.
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Tony I use a 3-gallon Solo sprayer. With 3 gallons I sprayed two large trees, a Cara Cara, and Saint Teresa Lemon. Medium sized Valentine pummelo, Dekopon, Marsh grapefruit, Ponkan all of which are planted in the ground., plus 9 or 10 container tees. You don't have to over due it just wet the upper and lower surfaces of the leaf. NOTE: NEVER spray a citrus tree with anything during the heat of the day. Spray in the morning or evenings, or on cloudy days. You can spray when the temperature will stay under 80-F.
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Great. I'll spray it today evening after work. I probably have to sell the extra to local. If I can't sell it, is it good for any other trees?. 1 click purchase from Amazon is not convenience sometime.
Thank you Millet for your info.
tony
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Tony, perhaps other members of this forum would like to purchase so low biuret Urea from you.
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Thanks Millet. Good info. My citrus (except kumquat and grapefruit) are all in flower bud now so it's too late for this regimen for me. However, due to a several day cold snap (~20F) here on the upper Texas Gulf Coast in mid-January most of my in-ground citrus pretty much kicked most/all of their leaves. They are generally leafing out with abandon now. Would this regimen have worked had I sprayed prior to the cold weather?
Thanks
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To obtain the best results of developing a good crop, low biuret urea should be sprayed 30 to 45 days prior to bloom. However, after the bloom is completed (after early drop) a foliar spray of low biuret urea greatly helps with obtaining fruit of good size and quality.
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well my berott reading is very different and i have no idea how to interpret it.....this is what it says = Mx beiret 7.8 grams biuret/kg N
what does that mean please?
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if writing berott you mean BIURET then your urea fertilizer has approximately 0.36% of biuret
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Lory....cool thanks for that......mine is good then.....
Millet.....is it good to spray pre autumn flush?....plus my lemons are still growing.
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Low Biuret Urea is normally foliar sprayed a month before expected flowering, again after early drop, and once more after what is called in the northern hemisphere as June drop (late drop) although it does not always occur in the month of June.
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I have fed my citrus inground with soluble fert high in nitrogen(made up of urea) and they have really responded to the urea ......leaves look great.
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My trees are about 70 percent through the bloom, and are now in the stage where the majority of the blooms have turned into small 1-mm fruitlets, In a week or so the tree will finish deciding how many of the fruitlets it is capable of retaining and bring to maturity, then dropping the rest, which is the called Early Drop period. After that it is time to make the second foliar spray application of low-biuret urea, which will increase both the fruit size and fruit quality.
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Hello, Millet. I sprayed my trees with low biuret urea at the concentration you recommended. After spraying, I noticed that two trees, an Australian red lime and one of two trifoliate citrus trees (same but unkown variety/species) showed damaged leaves - brown tips. This is only two trees out of about 55 trees and about 30 varieties. My point is that urea spray is not always innocuous.
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Great. I'll spray it today evening after work. I probably have to sell the extra to local. If I can't sell it, is it good for any other trees?. 1 click purchase from Amazon is not convenience sometime.
Thank you Millet for your info.
tony
I'm curious about the "Good for other trees?" question as well. In my online research, I didn't arrive at a definitive answer as to whether LBU is recommended for other fruit trees, such as Avocado, Peach, Plum, Cherry, Fig, Berries, and so forth. Anyone care to comment?
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My attention is mostly on citrus. I don't know the nutrition needs of many of the other fruit trees, I did spray LBU on my in ground Pomegranate this year at the same time as I sprayed all of my citrus trees. I can tell you this from my observation. The pomegranate flowered and set more fruit this year than any of the previous years growing this tree. 2018 is going o be a huge crop. Also, I remember reading an article of foliar feeding a fruit tree with LBU, but I don't remember what the cultivar was.
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Where would you begin to look at getting urea? I'm interested in seeing some pricing on it. Is it available online, or z_willus_d do you know where to get some locally? I pass through lincoln/roseville almost weekly on my way to auburn.
My orange tree is almost done blooming and there's alot of fruitlets on it Pomello and possibly lemon soon to follow.
Does anyone know if this works on persimmons? The bees are very busy this year and I can hardly hear if I go under one of my trees....
Thanks,
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Where would you begin to look at getting urea? I'm interested in seeing some pricing on it. Is it available online, or z_willus_d do you know where to get some locally? I pass through lincoln/roseville almost weekly on my way to auburn.
My orange tree is almost done blooming and there's alot of fruitlets on it Pomello and possibly lemon soon to follow.
Does anyone know if this works on persimmons? The bees are very busy this year and I can hardly hear if I go under one of my trees....
Thanks,
Hi Zephian, I ended up buying it on Amazon here:
https://www.amazon.com/gp/product/B0054PA524/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1 (https://www.amazon.com/gp/product/B0054PA524/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1)
And the surfactant here:
https://www.amazon.com/gp/product/B01LZAPHMV/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 (https://www.amazon.com/gp/product/B01LZAPHMV/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1)
You can find much better deals in bulk on ebay and probably at a local Ag distribution, but I didn't want to have a ton of this stuff in storage, as I understand the B builds up w/ time and heat so the LBU becomes not so L. I'm still dithering a bit on whether I want to use the LBU, since it's not strictly organic so far as I understand, but I will probably give it a try on a a few trees to see how they compare with untreated. It's not scientific, but if I don't see any obvious improvement to the fruit (Size, quality, health of tree), I'll probably forego in the future. As far as breaking the organic chain, this one seems pretty safe and innocuous for us humans.
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“, as I understand the B builds up w/ time and heat so the LBU becomes not so L.”
Good info on the way low biurett breaks down. So I bought some low biurette and am storing it in my garage. I have about a years worth. How quickly does this change occur? Summer is coming and my garage gets quite warm here on the upper Texas gulf coast.
Thanks
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“, as I understand the B builds up w/ time and heat so the LBU becomes not so L.”
Good info on the way low biurett breaks down. So I bought some low biurette and am storing it in my garage. I have about a years worth. How quickly does this change occur? Summer is coming and my garage gets quite warm here on the upper Texas gulf coast.
Thanks
I think I picked that idea up from others on this forum, but I'm having trouble finding anything on the web to back it up. Regardless, I will store any excess Urea products in a cool dry place indoors.
I found this article informative:
http://managingnutrients.blogspot.com/2013/01/biuret-in-urea-fertilizers.html (http://managingnutrients.blogspot.com/2013/01/biuret-in-urea-fertilizers.html)
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I used the low biuret urea (https://www.amazon.com/gp/product/B007OAYGEA/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 (https://www.amazon.com/gp/product/B007OAYGEA/ref=oh_aui_search_detailpage?ie=UTF8&psc=1)) and the leaves on almost all of my plants developed brown tips, i.e., chemical burn. I used 100g urea/gal and
1 Tsp Hi-Yield Spreader Sticker/gal.
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Vlad, sorry to hear that. What % biuret did your urea contain? What time of day did you spray? Over all my sprayings, and I have sprayed all varieties of citrus with low biuret urea, with the addition of a tsp of TW-20 surfactant per gallon I have never seen any leaf damage at all - none, but have seen wonderful nutritional results.
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I used the low biuret urea (https://www.amazon.com/gp/product/B007OAYGEA/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 (https://www.amazon.com/gp/product/B007OAYGEA/ref=oh_aui_search_detailpage?ie=UTF8&psc=1)) and the leaves on almost all of my plants developed brown tips, i.e., chemical burn. I used 100g urea/gal and
1 Tsp Hi-Yield Spreader Sticker/gal.
That looks like the one I just sprayed on my citrus -- same concentration. I haven't observed any leaf burn, but I do see a light white residual on the leaves here and there. I washed the residual off with fresh water the day after application, but it somewhat remains. I made the mistake of spraying a bit of the same on about half of my tomato seedlings just to see if I could give them a N-push (they're small for their size this time of year), but it burned the edges of all the tomato leaves. It's not going to be fatal, but it's certainly not helping. I can post an example of the two described leaves later.
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z-willis you should not have washed off the white residue, doing so took away urea's advantage.. The white residue was urea. A plant's leaf can only absorb nutrients applied as a foliar spray as long as the spray remains wet on the leaf. Urea has a big advantage over other nitrogen sources in that urea is VERY hydrophobic. When the humidity rises the dried urea foliar solution will re-hydrate and the tree once again absorbs more nutrition. No other nitrogen fertilizer has that ability.
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z-willis you should not have washed off the white residue, doing so took away urea's advantage.. The white residue was urea. A plant's leaf can only absorb nutrients applied as a foliar spray as long as the spray remains wet on the leaf. Urea has a big advantage over other nitrogen sources in that urea is VERY hydrophobic. When the humidity rises the dried urea foliar solution will re-hydrate and the tree once again absorbs more nutrition. No other nitrogen fertilizer has that ability.
Millet- I had a sense the residual was was Urea power, but I was a scared after the burning on the tomato plants, and I also figured the re-hydration would give the N another change to leach into the leaves (what washed off would just meet the soil below. I'm still seeing a good deal of white powder on the citrus, so I'm sure there's plenty to go around. Here are the promised pics fresh off the Android.
Burned tomato leaves:
(https://s31.postimg.cc/qumh8vign/20180505_154815.jpg) (https://postimg.cc/image/qumh8vign/)
(https://s31.postimg.cc/700fmrayv/20180505_154837.jpg) (https://postimg.cc/image/700fmrayv/)
Less-burned (or possibly totally unaffected) Blueberry leaves:
(https://s31.postimg.cc/ip4faqhd3/20180505_154933.jpg) (https://postimg.cc/image/ip4faqhd3/)
(https://s31.postimg.cc/587grverb/20180505_155143.jpg) (https://postimg.cc/image/587grverb/)
(https://s31.postimg.cc/ynd50vr0n/20180505_155334.jpg) (https://postimg.cc/image/ynd50vr0n/)
Unaffected Citrus leaves:
(https://s31.postimg.cc/ynd50wlvr/20180505_155215.jpg) (https://postimg.cc/image/ynd50wlvr/)
(https://s31.postimg.cc/f5ihkywnr/20180505_155227.jpg) (https://postimg.cc/image/f5ihkywnr/)
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For comparison, here's my "Buoi" pummelo leaves look like, before and after:
A moment before sprayed, April 29 2018:
(https://i.imgur.com/vnoh6yTl.jpg)
Today:
(https://i.imgur.com/4T8a4zml.jpg)
Like some of you, I also used that same Low Biuret urea from Amazon, at Millet's recommended concentration: 100gr/G with a teaspoon of stickler-spreader; sprayed once under, and once on top of the leaves...
So, a thank you again to our moderator for sharing a good advice, I think my pummelo (and probably my all other citrus trees) leaves look much greener now... :D
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I used the same low biuret urea others on this thread have used. Perhaps the problem was caused by the Hi-Yield Spreader Sticker?
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There was a study of surfactants done several years back. The aim of the study was to determine the best, and as important, the safest surfactant for citrus applications. The surfactant turned out to be TW-20 (also known as Tween-20 and Polysorbate-20). You can find this study in the text 'Advances In Citrus Nutrition'.Another good aspect of TW-20 is that the surfactant is food grade.
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Its time again. I have some grafted varieties and have some small fruits. Is is it safe to do foliar feed again?
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I take it your in Fountain Valley California. The fruit on your tree should now be in the cell division stage. This second spray of LBU is to extend the length of the cell division stage, thus producing larger fruit. As long as their is no blossoms currently on your tree (and at this time of year the flowering period should be well over) then yes it should be completely safe to spray.
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I followed Millet's recommendations for feeding and spraying my citrus this year, and all of my trees (save for a 2nd year Golden Nugget that set just one fruit) are holding 2-3x the fruit as they were last year. I know comparing one season to the next is not particularly meaningful statistically, regardless, I do believe this regimen has helped. The trees aren't the most beautiful. They are sandwiched next to my house on the East side and receive only morning and early afternoon light.
Below are a couple pics through the home window at the Washington navel, holding 45+ fruit. All of these trees are containerized, and it's a miracle they are still limping along 7 years after transplanting.
Thanks for all the great forum tips and support Millet!
(https://i.postimg.cc/gLKpYWyP/20181125-094529-resized.jpg) (https://postimg.cc/gLKpYWyP)
(https://i.postimg.cc/fk7D7xGg/20181125-094547-resized.jpg) (https://postimg.cc/fk7D7xGg)
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I used this method on all my citrus trees ...some in ground and some pots plus my friends 9 trees in ground.........they all responded with loads of blooms.....nice one millet.......i have been foliar feeding with a seaweed and fish emulsion blend since and this is well liked by the trees too.
The guy i buy my trees gave me a really useful tip as well........he said never to feed at soil or foliar feed when any plant is starting to flower or in flower as it disrupts the growth cycle..........That explains why all my eureka lemons dropped last year at flower stage......very good tip......
Now i just wait for the flowering to finish before i feed at all....even my strawbs.
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nice one z willis ;)
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update.....i sprayed my trees one month before spring bud break and they all flowered prolifically..........some of them are covered in tiny little fruits and flowering has finished.......i sprayed again and went away for two days......all the little fruits doubled in size over those two days(early fruit drop).....leaves have gone darker green on a lot of trees as well...........so when do i do the final spray of urea then millet please?
Summer has just started here now.(Dec 1st).......it was 40C today..... Evil hot.
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I followed Millet's recommendation on all my citrus trees as posted here.
I just want to share my young Pummelo tree, about 10-12 feet tall now,
only showed 5 dropped flowers last year, now is holding 9 sizing up fruits:
(https://i.postimg.cc/QBpQzqFs/Buoi-Dec1-2018.jpg) (https://postimg.cc/QBpQzqFs)
I think that the extra Low Biuret spray applications have positive effect,
so thanks again Millet! Will do the tasting pretty soon...
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Dear Millet.......I am going to spray my trees for citrus leafminer with neem oil mixed with another oil(eco oil).........Would it be good to apply a small amount of urea with this mix as well.....was thinking the oil would help to seal the urea underneath its coating.........good idea or silly Millet?
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Laidback, I don't think neem oil will do much to take care of leaf miner. Because urea is a very hydroscopic chemical it should be sprayed with water. The tree can only absorb urea when it is in the liquid state. Even when urea dries on the leaf surface, it will rehydrate itself when the humidity raises once again.
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I have tried many oils to treat leafminer.......its a real problem where i live........the neem oil is very good as it soaks into the leaf and actually kills the grub........all the others just provide a coating on the leaf.....therefore making it difficult to get in...........i was told by my citrus man to combine the two for better effect and its the best i have found so far......the eco oil or pest oil on its own did nothing to deter them..........this mix of the two i have found to be 95% effective....still some but not much..........i have mixed in a little fish/seaweed fert with the above before and that has had good results but i will do the urea on its own then........thanks for that. ;).....with the urea drying.........i saw white powder stuff around the fruits at the base of quite a few fruits on a couple of trees....thats the dried urea is it?
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Yes it is the dried urea. With high humidity the white residue will once again re=wet and be available to the tree.
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Just a friendly reminders, bumping this Millet's thread, that it's time now for Northern Hemisphere growers to start with the 1st Low BiUret sprays routine for your citrus trees. I had great results on my 2 fruiting trees: bountiful Kishu mandarin and 1st time fruiting on "Vietnam's" pummelo.
I just did mine today...
Wondering what happen if you miss the 1st spray, can you still get the same result if you add extra concentration on the 2nd?
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When foliar feeding with the urea, should I spray the underside of the leaves too?
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Any San Diegans know if the urea at City Farmers is Low Biuret?
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It is not recommend spraying extra amounts of Low Biuret urea if you missed one application period.
edweather, most definitely spray the underside of the leaves, as the underside of the leaf contains by far the most stomata (openings) in the leaf.
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Will low temperatures (mid thirties) in the immediate forecast prevent me from spraying the low biuret on my trees. Don't want to hurt them.
TFN
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Is it too late to apply the foliar feeding of urea?
I'm not sure if I have a low-biuret version of urea. This is the one I'm thinking of buying:
https://www.amazon.com/dp/B0054PA524/ref=psdc_3752891_t1_B007OAYGEA (https://www.amazon.com/dp/B0054PA524/ref=psdc_3752891_t1_B007OAYGEA)
Along with:
https://www.amazon.com/Bottle-Polysorbate-FOOD-GRADE-KOSHER/dp/B01FY41OOM/ref=sr_1_5?keywords=Polysorbate-20&qid=1548059943&sr=8-5 (https://www.amazon.com/Bottle-Polysorbate-FOOD-GRADE-KOSHER/dp/B01FY41OOM/ref=sr_1_5?keywords=Polysorbate-20&qid=1548059943&sr=8-5)
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That's it, you got it! Glad your first question got answered, I overlooked it, but didn't have the answer anyway.
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Bonsai Beast, I assume your tree has not begun to flower in your area. You can apply low biuret urea if the bloom has not yet started. It would have been better if you had sprayed 1.5 to 2 months prior to expected bloom date, but a late spray will still be better than no spray. Then after your trees bloom, new fruitlet set, and the early drop period (where the tree drops some of the small fruit that it set) a second urea spray should be given.
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Thanks for reminding me to spray it. I still have some Grapefruit and Limes - should i plug them off before spray?
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Tony, do you mean by "plug" to pick the fruit before you spray low biuret urea?
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Yes. Should i wait for or just pick them all then spray low biuret urea?
Grapefruit is almost yellow the while fruut. Some limes are still small and some are almost ready to pick.
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Existing fruit still on the tree is of no concern. You can spray the tree with low biuret urea with or without fruit on the tree. The only concern is open flowers. Never spray anything while the tree is in open bloom.
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nice. thank you Millet for answering my questions.
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Winter prebloom foliar spray application of low Biuret urea is known to greatly increase flower number, thus greater crop yield. Proper timing is important to achieve the desired outcome. Winter prebloom sprays are designed to increase flower number and fruit yield without reducing fruit size. Winter prebloom foliar sprays with low biuret urea (46-0-0 >0.5% biuret) is applied at the rate of .44-lbs. (200-grams) in 2 gallon of water plus one teaspoon of a good surfactant per gallon.. For large area sprays (acres) 50-lbs. per 225 gallons water. NOTE: a second low biuret urea foliar spray should also be done after early fruit drop and June drop periods to insure an increase in fruit size. In most areas this would be around July 1 to July 20.
So that's 3 applications: pre-bloom, after bloom fruitlet drop and then the "June" drop?
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Yes 3 sprays as per the above schedule
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Would spraying with urea help seedlings grow faster?
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Perfect. Thanks Millet. You make my day.
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Didn't get much of a June flush on our small grapefruit and orange tree, and no new blossoms. About 70 oranges set on the orange tree, and about 10 grapefruits. Do I still need to do a third spray? Thanks, Ed
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3d spray is to enlarge fruit, If you wish larger fruit. The first spray, 2 months befpre expected bloom date is very important in setting a good bloom. Did you do the first spray, and was it a couple months before expected bloom?
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Thanks for your reply. Yes, did the first spray in January, 6-8 weeks before bloom, and the second spray after blossom drop and fruit set. We wouldn't mind a bit larger fruit, so it sounds like a GO on the third spray. The oranges are a bit larger than golf ball size now. Ed
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One EXTREMELY important item, be absolutely sure to NEVER EVER let the a citrus tree's root zone become low on available water. Even semi dry. Doing so is a big timel killer of the bloom.
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Thanks, I will definitely keep that in mind. We have sandy soil here, and I was soaking the root zone twice per week during our dry spring. It doesn't take long for the soil/sand here to dry out. The rapid drainage, plus the heaving drinking of the citrus is a bad combination. We had an inch of rain here two days ago, and the root zone is almost dry now.
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yes, sandy rapid draining soil, is a problem when it comes to maintaining an even moisture level in the tree's root zone. Try your best when the tree is in bloom. The bloom lasts a couple weeks +or -.
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Time to bump this thread. It's been a mild winter here, and we will need to spray soon. I waited until mid January last year, and that seemed a bit late. Looking for a break in the wet weather, and a spraying we will go.
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Yes, now is the time for the first spray of Low biuret Urea. All in all, the Urea spray program consists of 2 different sprays. The first foliar spray, the winter prebloom spray (now) is designed to increase flower number and yield of commercially valuable-sized fruit without reducing fruit size. The second low-biuret urea foliar spray is designed to increase fruit size without increasing yield. The 2nd spray extends the cell division stage of fruit development to achieve an increase in fruit size. This second stage (cell division stage) end is characterized by maximum peel thickness. Low-biuret urea second spray is most effective when applied between July 1 and July 20. All applications should be made to give good canopy coverage. For the up most foliage absorption, solutions should be between pH 5.5 to 6.5. I use distilled water instead of my residential water supply. All sprays should be made when the air temperature is below 80-F. Taking into consideration the potential maximum daytime temperatures, applications should be made in early morning or late afternoon to early evening. Thank you Edweather, for bringing this to our timely attention.
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Is (NH2)2CO the same as low biuret urea? I ordered low biuret urea from Alpha Chemical through Amazon last fall and just now noted it had this chemical formula on the label. There was no other verbiage on the package.
Thanks in advance
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Y0rg0s - YES
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..... All sprays should be made when the air temperature is below 80-F. Taking into consideration the potential maximum daytime temperatures, applications should be made in early morning or late afternoon to early evening. Thank you Edweather, for bringing this to our timely attention.
For us non-greenhouse citrus growers it's unlikely temps are ever below 80 down here on the upper Texas Gulf Coast in July (at least here in Houston, day or night). And the rule that one shouldn't ever spray when temps are above 90 means a dark of night spray regime in the summer. I imagine these temperature spray guidelines would also hard to follow in Florida and parts of California.
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..... All sprays should be made when the air temperature is below 80-F. Taking into consideration the potential maximum daytime temperatures, applications should be made in early morning or late afternoon to early evening. Thank you Edweather, for bringing this to our timely attention.
For us non-greenhouse citrus growers it's unlikely temps are ever below 80 down here on the upper Texas Gulf Coast in July (at least here in Houston, day or night). And the rule that one shouldn't ever spray when temps are above 90 means a dark of night spray regime in the summer. I imagine these temperature spray guidelines would also hard to follow in Florida and parts of California.
We dont need to spray with anything to get good fruitset around here. Never heard of anyone doing this and trees are loaded everywhere I look. Almost every house grows citrus around here.
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Spaugh, the guidelines for the low biuret urea spray program is indeed heavily followed throughout California's citrus growers. In fact, the guidelines that are posted in this thread are for California growers, and are published by the University of California Agriculture & Natural Resources in their publication "The Citrus Production Manual". No matter how good of a crop your tree produces, following the Citrus Production Manual's guidelines, your tree will produce a larger crop, and more importantly, a crop with a larger and better quality fruit.
Yorgos, night time spraying is the second best time to spray, whether its spraying for this program, or general foliar spraying. The absolute best time to foliar spray a citrus tree is in the early morning on a cloudy humid day.
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I understand the literature is from the UC but Im telling in the real world here in CA no one is doing this and tree are absolutely loaded everywhere I look. I have to thin the fruitset on my trees its so heavy.
Then again, I pile hundred of pounds of mulch under my trees and also give occasional citrus fertilizer. I think my tree is getting everything it could ask for in the ground. Most citrus farms have bare soil and probably not so healthy soil.
I know Im going against the grain here. Im just offering alternative opinion on this. Its something that is not necessary to get great citrus crops. The proof of that is in my yard. Im happy to post pictures. Could they be "better" crops from spraying urea? Maybe. Or maybe I would have more leaf miner or aphids or some other problems then need to spray with even more stuff to try and fix problems I created.
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Spaugh, your comments are always appreciated. I certainly don't agree with your statement that no one is doing this, as urea sprays are very common in the citrus world. If your tree is producing all you need, or want, than you certainly can, or cannot, do as you wish. I would agree with you that many home owners are not aware of the value that proper nutrition can do for a fruit crop. The urea spray program has long been a great value to a citrus tree's production, and more importantly to the quality of the fruit produced. Any way the best to you and your tree..
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I certainly don't agree with your statement that no one is doing this, as urea sprays are very common in the citrus world. I would agree with you that many home owners are not aware of the value that proper nutrition can do for a fruit crop. The urea spray program has long been a great value to a citrus tree's production, and more importantly to the quality of the fruit produced.
And yet home grown grown citrus is almost always better than what you get at the store.
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Spaugh, Yes & no
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I understand the literature is from the UC but Im telling in the real world here in CA no one is doing this and tree are absolutely loaded everywhere I look. I have to thin the fruitset on my trees its so heavy.
Then again, I pile hundred of pounds of mulch under my trees and also give occasional citrus fertilizer. I think my tree is getting everything it could ask for in the ground. Most citrus farms have bare soil and probably not so healthy soil.
I know Im going against the grain here. Im just offering alternative opinion on this. Its something that is not necessary to get great citrus crops. The proof of that is in my yard. Im happy to post pictures. Could they be "better" crops from spraying urea? Maybe. Or maybe I would have more leaf miner or aphids or some other problems then need to spray with even more stuff to try and fix problems I created.
I mulched my previously un-mulched citrus trees last fall and got much better quality/quantity from my trees.
I don't know what to do with it all. :( I thought about trying the urea but I don't know how I would get rid of all that fruit. My pomello broke because the fruit was to heavy. I had a wheel barrow full of 30+ fruits from the broken branch as big as my head.
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I also sprayed my dekopons, pomelo's, fingerlimes with this recipe, i used 1% biuret urea and so far the plants look good.
My dekopon fruits (first harvest) were all disappointing in taste, not sweet at all and no sour....i hope this spray can improve the fruitquality since my tree's bloom all year around it seems (except the fingerlimes which have never bloomed so far).
The dekapons get yellow spots from sunshine and the fruitflesh underneath that part is always dry and bad.that part also gets fungus/rotting easy..i will try to bag some to keep them out of the full sun, maybe it helps.
for Thai climate can we spray them every few months with urea? We don't have a cold winter like you guys have.
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Great. I'll spray it today evening after work. I probably have to sell the extra to local. If I can't sell it, is it good for any other trees?. 1 click purchase from Amazon is not convenience sometime.
Thank you Millet for your info.
tony
I'm curious about the "Good for other trees?" question as well. In my online research, I didn't arrive at a definitive answer as to whether LBU is recommended for other fruit trees, such as Avocado, Peach, Plum, Cherry, Fig, Berries, and so forth. Anyone
care to comment?
I sprayed my citrus yesterday and i did a mango as well....i just walked past that mango and it's flushing now at many spots...it had never flushed before but i bought it recently. A 10 feet tall tree in a 1 gallon pot...very tall in a tiny pot...
I will spray another mango tonight..it's also recently bought and has never flushed or moved.
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Time for the annual bump of this thread. I'm surprised every year at how early the blossoms appear here in SE Georgia. Will be spraying Jan 1, no later.
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I sprayed 4 days ago, and tonight it's raining. Do I need to re-spray? Thanks.
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I have decided to not foliar feed again. I used Millet's recipe for low biuret urea and Tween 20 and I got browning on the tips of new leaves. Older leaves are not affected.
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Vlad, that is why the tree is sprayed 2 months BEFORE expected bloom date (before the new flush of leaves)
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Vlad, that is why the tree is sprayed 2 months BEFORE expected bloom date (before the new flush of leaves)
Millet..what is the bloom date for southern california?
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Too late all my trees have flushed out but 1
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Millet, thanks for the clarification.
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For the first spray of low biuret urea (called the winter spray) the most effective application time in California is from December 15 to February 15 in most years, NOTE: this window was extrapolated from research conducted in southern California. (Citrus Production Manual)
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My trees all still have fruits.
Should I wait until post harvest?
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Seanny, you can still spray even though your tree still has some hanging fruit.
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Millet, I sprayed mine last month, and two are flowering now, but they have NO leaves, and haven't had for almost a year. They are in my greenhouse. What the heck am I doing wrong? I have been giving them Miracle Gro, and also a complete food that has all 14 nutrients.
Carolyn
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Some members might not know the reasons to apply the first spray , called the winter spray, of low biuret urea. This first spray is designed to increase flower number and yield of commercially valuable sized fruit WITHOUT reducing fruit size Later applications are better than those that are too early. This is because once this opportunity to increase flower number has passed, late applications of low biuret urea will still increase the retention of abscising reproductive organs. Citrus Production Manual
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Daintree are you saying that your tree has not had any leaves for a year?
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will ammonia sulfate work. I have access to ammonia sulfate 21-0-0
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Daintree are you saying that your tree has not had any leaves for a year?
Yep. I keep thinking it will flush, but it just puts out more flower buds! It is 6 years old and did really well up until last winter. All the leaves dropped, and no amount of light or fertilizer would help. I will go get a pic right now. Soil drains well.
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Checked the tag, I have had it since 2017. January of 2020 all the leaves dropped. The pic shows tiny flushes of leaves, but they have looked like that for months. The tiny leaves never get anyy bigger. 1/4 mm long.
I am SO ready to give up on citrus all together, unless I can get this figured out.
This is it. I call her "Baldy" :)
(https://i.postimg.cc/qgQ4CQ8v/6-C88-C794-F655-4-FF9-BD0-C-5-E17-EC5-EC523.jpg) (https://postimg.cc/qgQ4CQ8v)
You can see a tiny cluster of leaves. It pushed these out this summer and this is all the bigger they got.
(https://i.postimg.cc/56RJs0Kc/D8-F2-D7-BC-2183-4-CF5-9469-1-FC3849-F8600.jpg) (https://postimg.cc/56RJs0Kc)
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The reason Urea is used to supply nitrogen via foliar spays, is because the time for 50% leaf absorption of the chemical is only 1/2 - 2 hours. Many chemicals take days or weeks. The best time to apply foliar fertilizers is early morning, when the plant's stomates are open.
If temperatures are projected to reach approximately 85-F or higher during the day, applications should be made just after daybreak or after the temperature drops in the evening and the relative humidity increases. Winter applications should be made at midday, when temperatures are suitable warm. Avoid spraying to runoff. Excessive liquid per tree causes pooling of the fertilizer at the tip of the leaf, which can result in tip burn. Nutrient uptake is best when the application solution is at a pH from 5.5 to 6.6 . Last note: For most cation nutrients (magnesium, potassium, zinc manganese and iron), application as a sulfate salt is equally effective as chelated products and less expensive.
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The reason Urea is used to supply nitrogen via foliar spays, is because the time for 50% leaf absorption of the chemical is only 1/2 - 2 hours. Many chemicals take days or weeks. The best time to apply foliar fertilizers is early morning, when the plant's stomates are open.
If temperatures are projected to reach approximately 85-F or higher during the day, applications should be made just after daybreak or after the temperature drops in the evening and the relative humidity increases. Winter applications should be made at midday, when temperatures are suitable warm. Avoid spraying to runoff. Excessive liquid per tree causes pooling of the fertilizer at the tip of the leaf, which can result in tip burn. Nutrient uptake is best when the application solution is at a pH from 5.5 to 6.6 . Last note: For most cation nutrients (magnesium, potassium, zinc manganese and iron), application as a sulfate salt is equally effective as chelated products and less expensive.
Millet..what product is sulfate salt for those cation nutrients?
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Iron Sulfate, Copper Sulfate, Zinc sulfate & Manganese sulfate.
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Very warm December has started pushing new growth, and some tiny blossoms are showing. Normally wouldn't spray into mid Jan, and normal bloom time is around first week in March. Jan-early Mar, can still have frosts and freezes. Am thinking I just want to stick to normal spraying and fertilizing schedule, and not force more tender growth vulnerable to freezing. Does that sound right?
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I have Ammonium sulfate 21-0-0 Do I have to worry about BIURET in my feed
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Anybody have recommendations on where to get some low buiret urea? Having trouble finding it for sale.
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Not sure how much you need, but ebay has it. Sold as Urea, by Alpha Chemicals.
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I have Ammonium sulfate 21-0-0 Do I have to worry about BIURET in my feed
I wouldn't think so, you could contact the manufacturer to see if there is any Urea as impurities.
Do you normally use Ammonium Sulphate ?? It may tend to drop pH, but that may be useful to balance hard water.
You may want to consider Ammonium toxicity problems, rather than Biuret toxicity.
Just watch the strength of your feeds, and don't apply in cool dull weather.
https://www.pthorticulture.com/en/training-center/ammonium-toxicity/
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Not sure how much you need, but ebay has it. Sold as Urea, by Alpha Chemicals.
Couldnt find anything about its biuret %. Is that what you use for your plants?
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I have Ammonium sulfate 21-0-0 Do I have to worry about BIURET in my feed
I wouldn't think so, you could contact the manufacturer to see if there is any Urea as impurities.
Do you normally use Ammonium Sulphate ?? It may tend to drop pH, but that may be useful to balance hard water.
You may want to consider Ammonium toxicity problems, rather than Biuret toxicity.
Just watch the strength of your feeds, and don't apply in cool dull weather.
https://www.pthorticulture.com/en/training-center/ammonium-toxicity/
I have Blue berries, 7.8 pH hard water and soil just under ph8 The blueberries explode with this
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Iron Sulfate, Copper Sulfate, Zinc sulfate & Manganese sulfate.
Another benefit to allpplying metal sulfates is that they tend to be fungicidal (especially copper and zinc) and will probably result in cleaner fruit with fewer blemishes.
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That Urea I mentioned is low biuret .There is other discussion about it in this thread. It's what I use.
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https://www.homedepot.com/p/Sunshine-Harvest-9-lbs-Shaker-Jug-Urea-Fertilizer-UGF-9/316885113
Is this one considered low biuret? Thanks
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It is labeled Diammonium Phosphate.
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It is labeled Diammonium Phosphate.
I think they used the wrong pic. Here’s the product description
Just Scentsational's Sunshine Harvest 9 lbs. shaker jug of urea is a 99% pure nitrogen boost for the fastest possible green up. Simple, easy and quick to apply this fast release formulation. Aids in greening up lawns, vegetables gardens, flowers, trees and shrubs. Water after application for direct and fastest ground absorption. NPK 46-0-0 Size: 9 lbs.
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Could be low biuret, but if the product label does not list the biuret content there is no way of knowing. If you can't find any I could send you a 5-lb. jar of low biuret urea (0.5% biuret).
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Could be low biuret, but if the product label does not list the biuret content there is no way of knowing. If you can't find any I could send you a 5-lb. jar of low biuret urea (0.5% biuret).
Thank you so much for your kindness. Sending you a PM
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This is my normal spraying time, but December was so warm, there is already new growth and small blossoms showing up. Can I still spray, or is it too late.
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To late to influence the bloom. The next urea spray which is designed to increase fruit size is between July 1 and July 20.
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Millet, second spray on Mother’s Day? Third spray, Father Day? This adjustable sprayer is perfect for over/under spraying, very fine mist. I spray more than 3 times for my citrus but also for my other trees. Bought a bag, which is more than enough for all my trees for the next 3 years that’s why I store it in a sealed container.
(https://i.postimg.cc/yWpYD2Hd/6-A6399-C0-53-EC-48-C6-9334-D7-A7-EF533652.jpg) (https://postimg.cc/yWpYD2Hd)
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Thanks so much to Millet. I just gave my golden nugget mandarin tree (with Sumo and Pokan grafted) a spray.
Last year only Sumo set like a dozen fruits. No fruits for golden nugget-hope this year it’s more productive.
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Urea from Alpha Chemicals caused extensive burning of leaves. Defoliation goes from none to complete leaf loss depending on the plant. There is some minor damage on most trees.
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My best guess either the spray was over applied, sprayed in the heat of the day, or not a low biuret variety
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My best guess either the spray was over applied, sprayed in the heat of the day, or not a low biuret variety
I believe it is not low biuret. The package did not indicate. The data sheet said it was low biuret.
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I tried urea from Alpha Chemicals once and it caused burning and defoliation. Their specification sheet says that biuret is less that 0.5%, which I believe is considered "low"biuret". Their spec sheet is here: https://alphachemicals.com/msds___specs
I do not know if I over applied it because I do not know what is meant by "over applied". I sprayed both sides of leaves until I saw it dripping from leaves. This was done indoors and trees were kept indoors under lights.
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I've used the Alpha Chemicals urea many times with no problems.
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I have never had a problem. I'm sorry you have.
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Would a spray & drench of this help (i know it's late) my Flame grapefruit & Ortanique orange?
Ed
(https://i.postimg.cc/tYZzV58m/FEAA3262-6-A5-D-4487-B996-DB2150-A77-DA4.jpg) (https://postimg.cc/tYZzV58m)
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I have used Alpha Chemicals since 2019 and not had burning.
Perhaps do another limited test application?
Are you sure the dilution rate was correct?
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Do you spray a single application per cycle or multiple? I’m thinking is single but not 100% sure.
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Single. Spray to get good coverage, upper and lower leaf surface, but do not over soak the tree.
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Just finished spraying all my citrus trees using AC urea. I have not noticed any burned leaves using the AC urea.
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My citrus are only in the ground 1-2 years (all my 14 or so citrus were extirpated by Winter Storm Uri Feb '21) and are currently not holding fruit. Does this foliar spray benefit a tree without fruit? BTW, I do have my trees on a regular fertilizer regimen, fertilizing them 3-4 times a year.
Thanks
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For a tree without fruit, the urea spray would just be a general nitrogen source.
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Does citrus absorb urea from the roots as well, or is soil soak useless? Is this an environmental concern?
If I use a decreased amount in my spray, say 1 tablespoon per gallon, can I spray more frequently like bi-weekly. Will I still have high risk burning leaves in hot weather?
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Yes, But for soil application through the roots you would be better off using a ammonium nitrate formula.
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Do you mean ammonium sulphate
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Find a fertilize that contains all three major ingredients N, P and K plus race elements.
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"It is labeled Diammonium Phosphate.
Could be low biuret, but if the product label does not list the biuret content there is no way of knowing."
As far as I know, unless it contains Urea, Biuret shouldn't be an issue because the N is Ammonium.
Otherwise the Biuret warning would apply to other N fertilisers.
Not sure if the Ammonium breaks down to other forms ( urea ?) but without the manufacturing process heat, don't think the Biuret compound can form easily.
ps Ammonium fertilisers also have some warnings, i.e. in cool dull weather plant roots can get problems.
"I tried urea from Alpha Chemicals once and it caused burning and defoliation. Their specification sheet says that biuret is less that 0.5% "
Biuret causes a toxicity symptom. white or yellow leaf margins, plants stop growing.
Low Biuret Urea at high rates, or rates too high for young plants, or not sufficiently mixed and agitated well will still cause burning.
Dog Pee on lawns causes burnt grass.
I once fertilised Citrus seedlings with a liquid Urea fertiliser, Citrus was ok but small Microcitrus dropped their leaves.
Also they got it at the end of the vat, so could have been a heavier concentration slug in the last of the vat.
Since then I increased the agitation of spray mixes, i.e. a circulating return off take on a pump, or occasionally shaking a hand sprayer to re mix spray liquid.
Urea can be harsh at high rates, it is recommended to use it to clean out other chemical residues in farm spray vats.