The Tropical Fruit Forum

The last year or so I was using Epsoma Citrus Tone to fertilize all my in ground citrus, feeding generally Feb - Aug every 6 weeks or so.  This spring I switched to a locally blended commercial fruit tree mix 18-9-11, which is much cheaper than the Epsoma Citrus Tone.  Also last year I did scatter some Azomite around all my fruit trees for the micro nutrients, and last year I added Epsom Salts around all my citrus, as my soil generally is extremely deficient in Magnesium, again same amount around the other younger citrus.  Soil testing this spring from the citrus area, still shows levels of Magnesium on the low side.   I have my citrus trees planted on a 25-30 foot spacing, arcing outward from my older mature citrus / fig tree, so root competition should not be a factor, also I have 3 other citrus trees planted about the same time on this arc (the one with the issue is 2nd from the end of the arc).

Can you clarify what is Vegan Fertilizer? For an Organic option Epsoma Citrus Tone 5-2-6 is fairly good at least for in ground use, though like most Organics it is relatively weak so requires about 3 times more fertilizer per tree than commercial fertilizer.  It is made primarily from processed Chicken Litter (chicken manure, feather mill, etc.).  For a pure Vegan fertilizer mix with no direct animal products in it, you might consider Down to Earth brand Vegan mix with a 3-2-2 NPK ratio as a start.  Though at 3-2-2 you will need about twice as many pounds of fertilizer per tree as Citrus Tone, or about 6 times as much as the commercial bend I use. 

From an economic cost of fertilizer difference, using online Amazon prices for Citrus Tone and Down to Earth Vegan fertilizer adjusted for effective strength per pound vs 1 pound of the commercial mix I use.

I get 69 units of Nitrogen per dollar in the 18-9-11 commercial fruit and nut tree mix I buy locally ($12.90 for 50#)

For Epsoma Citrus Tone 5-2-6 using the most economic $34  per 18 pound bag from Amazon, I get 2.64 units of Nitrogen per dollar

And using Down to Earth Vegan 3-2-2 from Amazon at $12.99 per 6 pound bag we get a cost of 1.39 units of Nitrogen per Dollar.

Or in other words using Down To Earth Vegan mix will cost roughly 50 times more than what I pay for a commercial fertilizer and twice as much as an organic Citrus mix.

Now sure both the Organic and the Vegan mix probably has a better assortment of micro nutrients than my commercial blend, but one can afford a lot of miro supplements for the cost difference and in the end we are looking at many of the same Elemental minerals from different points in the organic decay chain.

The attached photo is of leaves collected from one of my in ground young Satsuma trees in Louisiana.      The yellow leaf issue started about 6-8 months ago, and may be getting worse.  The vast majority of the leaves are still like the green one shown in the photo, however there are some solid yellow leaves, and  several of the blotchy ones.      The yellow leaves easily detach from the tree.   I have CLM on all of my 9 in ground citrus trees, though it tends to be worse later in the year, I also just discovered Cottony Scale on another of my young Satsumas which is planted about 50 feet away from the one where I collected these leaves.  The other trees appear healthy other than some CLM  damaged leaves.

thanks for your help
Ike

See attached soil test results


p.s. the following were add on test results were

organic content was 1.79%

Aluminum 2.29

Copper 0.30

Iron 81.3

Manganese 5.64

Zinc 0.85


The above sample was taken from the citrus plot after regular fertilizing the last few years, soil from un-fertilized nearby soil showed a Magnesium level of 34.3, otherwise very similar overall to the above.

p.s. root stock is not known on this tree, though it is likely a Citrange, not flying dragon

Over the last 2-3 years I have planted six new citrus trees to replace ones that I have lost to freezes over the years, and to augment the variety of citrus I am growing.  Most of these are Satsumas, all are growing in ground on the 8b/9a line in Louisiana, I also have 3 large mature Satsuma trees.  However no matter what I do the leaves on my Meyers lemon are always more pale than any of my other citrus.  I try giving it more fast acting nitrogen, and it greens up some, I try adding epsom salts (soil test show deficiency of Mg, along with just about everything else N,P,K, Cu, only Iron is in normal range in sandy loam soil), I have also tried just feeding it extra 18-9-11 fruit tree fertilizer blend with micros.  Each has made it look somewhat better, with the 18-9-11 fertilizer seeming to overall help the most, though it is still a bit more pale than my other citrus, and it requires frequent (monthly) feeding to keep it this way.  It has grown since being planted, but not nearly as fast as some of the other citrus that were planted at roughly the same time, some of which have went from 2 ft tall to nearly 7 ft tall in under 3 years.

So is this Meyer's just living up to its reputation of being picky and wanting more Nitrogen than other citrus, is there something else I can do, ...?

thanks

This brings up another good question, spray for CLM or don't spray?    In my case CLM  seem to effect less than 10-15% of my in ground  citrus tree leaves regardless of time of year.

Do you want a tree lined driveway, or do you want a hedge?

We ended up hitting 14F with wind blowing at 10+ mph here in western Louisiana last week, I had all my citrus covered with C7 Christmas lights or 250 watt heat lamps under the covers (tarps, sheets, blankets, whatever I could find) on each, which only helped so much.  I am still waiting to see the overall damage, 30-50% leaf drop on most of the trees so far, though with lots of curling dried out leaves still hanging on the trees.  While surveying the damage today I found one of my smaller (3 ft tall) 2nd year in ground Satsumas currently has a total of 4 leaves growing on a limb just above the graft line that look healthy, all other leaves on the tree a showing significant curling, drying, etc.  My meyers and Cara Cara seem to have fared better though the Cara Cara, now about 7 ft tall is showing lots of curling leaves.

Wait well into the spring or summer before giving up on it, I had freeze damage to a large limb on one of my in ground Satsumas a couple of years ago and that limb looked dead until August when it finally started sprouting new growth on about half its length, I am glad I waited to prune it back.

Over the last few weeks thanks to google  I have been reading scans of a variety of older 20th century scholarly works regarding growing citrus, and one of the things I noticed was a significant difference in reports of cold hardiness for various common citrus cultivars.  Not so much the absolute temperature values, but instead their relatively sequence  from most to least cold hardy.    One in particular that I noted, several of these mid 20th century works list Meyer's lemon as being almost as cold hardy as Owari Satsuma, which matches my observation of many people near where I live on the 8b/9a line having mature inground Meyers lemons growing in their yards that get no formal freeze protection yet continue to survive.

All of which leads me to ask, does anyone know of any modern detailed studies on cold hardiness of common citrus cultivars, I know there are many guides published by universities that list the often repeated numbers, but I have to wonder if that is all they really are, since based on comments on this and other web forums there seems to be a dependency in real world observations on cold tolerance of certain types of citrus, particularly Meyers lemons, and certain types of Grapefruit.

Well first off they may not actually both be the same variety of Satsuma even if they came from the same source.  As to the rest, I have 3 mature Satsuma trees (20+ years old), 2 of them planted about 30 feet apart, and the other in a more exposed location on the other side of the house over a hundred feet away,   and each year it seems a different one has the best flavor, though usually it is one of the 2 that are close together that has the best flavor.  My thought is this is based on variation in the growing conditions, amount of shade, exposure to colder winds in winter, etc.

Here in Louisiana we have two main citrus nurseries, until recently my understanding is both used Carrizo as their primary root stock, one of which also sells some dwarf versions on flying dragon.  I have recently learned that one of these nurseries (Saxon Becnel) is now primarily using Kuharski Citrange, which appears to be a Carrizo variant, except on Limes and Kumquats which they grow on C-22, which I believe are incompatible with Carrizo.  There seems to be little information online about Kaharski, and most of it is dated in the last few years.  In my research on this root stock , I noted that about 1/3 of Florida citrus was being grown on this root stock a couple of years ago.