Tropical Fruit > Tropical Fruit Discussion
Coconut deficiency and treatment
KarenRei:
As discussed here, somewhat offtopic:
http://tropicalfruitforum.com/index.php?topic=27233.0
... I've long been rather lax about my fertilizer routine, and am working to amend my wicked ways ;) In regards to this, I'm working to treat a deficiency in my Fiji Dwarf coconut. Symptoms:
* Deficiency in a mobile nutrient (N P K Mg Cl Mo Ni), as the symptoms are in the oldest leaves, while new leaves are just fine
* The main symptom is chlorosis, eventually progressing to necrosis. Chlorisis begins further down the leaflets, yellowing (pure yellow, not spotty/blotchy), affecting the central vein and the edges last.
* This, I understand, to be a symptom of K deficiency, which I also understand to be the most common deficiency in palms
Leaf that is mostly yellowed, but necrosis is just beginning at the tip:
Zoomed in to the necrotic portions:
Leaf with nearly-full necrosis next to it:
Section of a leaf going chlorotic:
Comparison between the basal portions of the necrotic vs. the yellow leaf:
Older images of an old frond (ignore the cutoff leaflets on the right):
Progression of yellowing up the same old frond, 2 1/2 weeks later (sorry for the red lighting):
Attempts at treatment thusfar:
* Started out rather half-arsed ;)
* First looked up *proper* fertilization for coconut palms, which for a palm the size of mine should be about 200 grams of my fertilizer I had been using** per month, plus extra potassium. I had probably been averaging about 50 grams, with no extra potassium - but it's hard to say because I hadn't been measuring. The fertilizer is 12-14-14.
* I started out just giving a proper single monthly dose at the start of the month, but that did nothing to reverse what's clearly been a problem that's built up over time.
* Over time I made minor, trivial additions of more potassium, magnesium, and trace elements, as well as starting foliar feeding (but AFAIK that was kind of hopeless for macronutrients like potassium)
* Eventually (~5 days ago?) I looked up how to treat a potassium deficiency, and found out that the amount of fertilizer I should be adding to remedy is huge, something like 1 to 1,5kg, and that it should be a 3:1 ratio of potassium sulfate to magnesium sulfate to avoid inducing magnesium deficiency. I've so far added about 400g, as I don't want to add it all at once (it's been in two doses so far)
* Today - although it's doubtful that it's the primary problem - I also added some (maybe ~80g) of sodium chloride (just regular table salt). Our water isn't chlorinated, so this tree has probably never gotten any added chlorine in its life, and my reading was suggesting that coconut palms are unusual in actually liking chlorine, and that addition of saltwater has been known to help perk them up. Adding salt to soil goes against every bone in my body, but....
The palm is 3,2m (10' 6") tall to the top of the highest fronds, with the fronds starting to separate at around 80cm up (2' 6"), and a trunk diameter of 10cm (4"). The soil depth is 60cm, and the pot is 80cm wide. So in gallons, that's probably around 50 gal. 5 fronds - 2 old fronds undergoing chlorosis / necrosis to varying degrees, 2 mature and mostly or completely healthy fronds, and 1 new frond opening up.
The other issue that comes to mind is root health. Shot suggested soil temperature, pathogens.
Soil temperature should be around 24°C (75°F), day and night, all seasons, at all depths. Air temperatures vary, and increase with height, but probably average around 30°C (86°F), and humid. I didn't used to, but I've taken to misting my plants several times a day as well.
I did have an outbreak of fungus gnats starting last month and peaking several weeks ago. Their numbers have been declining of late as I found a place where I could buy predatory insects (yeay!). They're still around, but not nearly as common. Apart from fungus gnats, the only other pest that I ever have had problems with is spider mites (they've killed more plants than I care to admit over the years). No unusual numbers of them of late, and I bought some predators for them as well just in case.
Aeration: the pots have holes drilled at the bottom, but they're such large pots, and plastic, and the soil is so moist, that obviously root rot is something to consider. Normally I try to prevent this simply by not watering the large pots too often, but now I'm facing conflicting interests; I have to water to rinse fertilizers into the soil (and the more I water, the deeper they'll wash in)... yet if root rot is of concern then I want to water as *little* as possible. I have no frond wilting, so that's a good start. I did - 2-3 weeks ago - drill a lot of side holes. I might go in at some point and double the number of side holes. I obviously don't want to go so far that I ruin the pot's structural integrity, or I'll have to coat it in fibreglass to reinforce it - but I could probably do more. Regardless, the soil is very moist right now. Question of whether I should be relocating the palm to outside the humidity tent to try to dry it out, or just backing off on waterings (aka, washing in nutrients) for a while. Again, there's no wilting, so maybe it's not a primary concern right now.
Thoughts, suggestions?
shot:
Calcium is very important, competing nutrients.
cocos really like heat, hot and wet is great now cool not so much
pics were good
I'm getting sleepy, have to call it a night
palmcity:
http://www.cropnutrition.com/potassium-sulfate
http://krishikosh.egranth.ac.in/bitstream/1/5810000191/1/Nakka%20Sathi%20Babu.pdf
Relationship of potassium to boron levels in leafs (updated as read more of material data reported)
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.512.9176&rep=rep1&type=pdf
http://www.kno3.org/en/recommendations/foliar-applications-of-potassium-nitrate
https://www.gardeningknowhow.com/edible/fruits/coconut/fertilizing-coconut-palm-trees.htm
;) https://laidbackgardener.blog/tag/coconut-palm-as-a-houseplant/
https://gardens.everybodyshops.com/grow-without-soil-indoors-with-hydroponics/
KarenRei:
--- Quote from: shot on March 18, 2018, 10:25:16 PM ---Calcium is very important, competing nutrients.
cocos really like heat, hot and wet is great now cool not so much
pics were good
I'm getting sleepy, have to call it a night
--- End quote ---
--- Quote from: palmcity ---http://www.cropnutrition.com/potassium-sulfate
http://krishikosh.egranth.ac.in/bitstream/1/5810000191/1/Nakka%20Sathi%20Babu.pdf
Inverse relationship of potassium to boron levels in leafs, but both are needed.
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.512.9176&rep=rep1&type=pdf
http://www.kno3.org/en/recommendations/foliar-applications-of-potassium-nitrate
https://www.gardeningknowhow.com/edible/fruits/coconut/fertilizing-coconut-palm-trees.htm
;) https://laidbackgardener.blog/tag/coconut-palm-as-a-houseplant/
https://gardens.everybodyshops.com/grow-without-soil-indoors-with-hydroponics/
--- End quote ---
Thanks for the advice. :)
There's no signs of calcium or boron deficiency. But it's probably wise to add some alongside the potassium and magnesium. I accidentally induced a calcium deficiency in one of my bananas while treating a potassium deficiency, and certainly don't want to do similar to the palm. And it's not like it's a calciferous soil (it's a mix of perlite, sand, and organic matter... more of the latter than I'd prefer, but I ran out of perlite and didn't want the weight to be too unbearable), so calcium is not unlimited.
Do you feel that the soil or air temperatures listed above (~24°C/75°F for the soil, ~30°C/86°C for the average air temp) are too cool? Raising temperatures is easy; lowering them not so much ;) This comes with caveats, however:
* If I raise the average temperature, then that raises the peak temperatures from fluctuations as well, and the near-ceiling temperatures (which are higher than average temperatures).
* I only have one environment for all of my plants to live in. I can adjust their individual temperatures to some extent with how high they're positioned on shelves, but this can't be done for large plants (in large pots) or climbers which cross many different heights.
I've lost a number of plants over the years to excess heat, but not a single one due to cold. So I'm always a bit apprehensive about deliberately elevating the temperature ;)
Potassium sulfate is indeed the form I'm supplementing with, as A) I saw it specifically recommended for treating deficiencies, B) I don't have potassium chloride on hand, and C) I don't want to be adding excess nitrate while treating a potassium deficiency :)
Re, "houseplants" - nothing I have is grown as a "houseplant", unless you consider most houseplants to be "plants grown in rain barrels inside humidity tents under a 4-to-5 meter ceiling with lights intense enough that they leave you seeing pink" ;) As for the claim that " the great botanical gardens of the northern hemisphere (Kew, Montreal, Berlin, New York, etc.) are not able to cultivate this large palm tree ", yes, they do. Kew, Berlin, and Eden even have Lodoicea! (That's actually my dream plant... unfortunately it's just not practical to grow, even in the large greenhouse project being planned here... too massive, too slow, too dioecious).
Re, the hydroponics article - heh, I'd love to see someone growing a full-sized coconut on hydroponics. ;) Shouldn't be impossible, but not a task for me! ;) I've done small scale hydroponics before, and I'll just say that the results didn't tempt me to switch over from soil culture (by and large it just adds new potential ways to mess up and kill your plants ;) )
palmcity:
I am not advocating you try this as I have not tried it as I only grow a few coconut trees around my house and have done little supplementing in my soil near the coconut trees. I may try adding some lower levels of borax/potassium but have not yet and it appears it takes 3-6 months to evaluate the results seen in the plants with changes so I will go slow to my additions of elements.
Hopefully a professional coconut grower will give their opinion, but I am not one.
You probably have the same opinion that I have if considering adding plant supplements, choose lower known values and increase to a higher if needed as removal is often difficult or impossible without plant death. If you already have your potassium level where you think it will be ok, you can still consider the addition of the borax.
Borax and potassium oxide were used in the report: http://krishikosh.egranth.ac.in/bitstream/1/5810000191/1/Nakka%20Sathi%20Babu.pdf on page 28
Notation for the treatments Levels of boron and potassium
• T1: B1K1 25 g borax/palm + 900 g K2O/palm
• T2: B1K2 25 g borax/palm + 1200 g K2O/palm
• T3: B1K3 25 g borax/palm + 1500 g K2O/palm
• T4: B2K1 50 g borax/palm + 900 g K2O/palm
• T5: B2K2 50 g borax /palm + 1200 g K2O/palm
• T6: B2K3 50 g borax/palm + 1500 g K2O/palm
• T7: B3K1 100 g borax/palm + 900 g K2O/palm
• T8: B3K2 100 g borax/palm + 1200 g K2O/palm
• T9: B3K3 100 g borax /palm + 1500 g K2O/palm
page 28
Continue monitoring levels of the other Ca, Mg, Cl, Na, etc. etc. etc. and soil ph, moisture soil & atmosphere, aeration soil & atmosphere, light source, temperature, etc. etc. etc.
Navigation
[0] Message Index
[#] Next page
Go to full version