Help with soils analysis please

10 years ago

Hello everyone. It's been a real struggle the past 10 years keeping my citrus in decent condition. I finally broke down and got a kit, one with the capsules of chemicals that you use to analyze PH and NPK in the soil. I was really surprised at the results.

I live in SWFL and I don't have soil, I have beach sand - literally no soil other than a little bit of organic material in the top 5" give or take. Below that, pure beach sand, no visible organic material at all. Go down about 30" and you can hit (in some places) a rock hard lime deposit

Soil here is supposed to be very alkaline for obvious reasons. My soil analysis showed a PH of 6.5 in two areas. I dug down about 4-5" to get the sample and followed directions carefully.

My trees have leaves that yellow while the veins stay green. Here's the breakdown of my soils analysis. I fertilized pretty heavy (at least 8 lbs of 10-8-10 per mature tree.)

Last year I had a health issue and could not take care of my trees, this year I'm paying for it. So far I've fertilized about 2 months ago and hit all my trees with neem oil and foliage nutritional spray.

They bounced back NICELY, greening up and looking good. A few days ago I noticed them crashing again, so I tested the soil. Here's the results, I tested in 2 locations that are typically well cared for, under the drip line of a tree about 4-5" deep.

Following directions carefully - my results were.

PH-6.5 (surprising, I was expecting at least 7.5). Nitrogen - virtually NONE, barely any color change in both tests. Phosphorous - very low in both tests. Potash - low to very low. I found it odd that the tests were so mixed

My plan, use up the last of the 10-8-10 with micronutrients that I have, feed heavy. Follow with a light application of something like 21-0-2 sod starter to get the very low nitrogen up, this would be a light application like I said, maybe a couple of lbs of that. Remember, my soil has almost no detectable N even after a heavy feeding about 2 months ago, although my memory could be off a bit, could be 3 months.

After that, wait after a few good rains, then retest the soil.

We've had a lot of rain lately, I'm thinking that the soil just CANNOT hold any nutrients, they just wash through the plant.

How does my plan sound? I'd appreciate input as I'd like to get it done ASAP.

Thanks again.

Featured Answer

hobbyartisan (Saskatoon, SK Canada, 2b)

10 years ago

Why don't you work on improving your soil rather than only applying ferts? Obviously I am not in a zone where you can grow in ground citrus but I have the same problem, my native soil is pure sandy silt. I am going to start a fruit orchard but first I have been working on building up my soil health by planting cover crops. This will be my second year of it and my soil still has a long way to go.

You can research cover crops that are shallow rooted and can grow near your citrus. You can also add organic compost by top dressing and keep testing new your soil until you get to better levels. Mulching often helps as well to bring beneficial insects and worms in to improve your soul structure but you will need to add some compost first so there is food for them first.

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Comments (11)

poncirusguy6b452xx
10 years ago
My plum tree does that so I am listening hear.
bruce5881
Original Author
10 years ago
You mean the leaf veins stay green, but the leaf in between the veins yellows? In citrus that typically means a mineral deficiency, usually zinc but could be magnesium or manganese. That's why I got up at 6 this morning and went out and applied another round of citrus foliage nutritional spray. That is SUPPOSED to be the best way to get minerals into the trees.
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Silica
10 years ago
The reason that your tests show no nitrogen nor potassium is because both elements are very water soluble. With each Florida rain both minerals are quickly leached away below the tree root zone. For this reason in Florida the Institute of Agricultural Sciences of the University of Florida advises that 5-year old citrus trees and older be fertilized 3 times per growing season. Common Fertilizers used on citrus in Florida are 8-8-8 and 10-01-10. The best to you and this tree. - Silica
pip313
10 years ago
How old are you, and how much work are you willing to do? Digging the tree up, removing all the sand, and putting it back while layering heavy with wood mulch would permanently add organic matter and help pretty much for ever. But by god it's a lot of work, could take years doing little by little.
poncirusguy6b452xx
10 years ago
Pip I am 59 years old and those days are over for me

The Cincinnati kid
pip313
10 years ago
Lol I was talking about the op
bruce5881
Original Author
10 years ago
I appreciate the input. This isn't a tree, it's about 20 trees so digging them up, etc. - not an option :-) About 12 or so of them I recently planted, I did a lot of soil prep for those, but to truly do it right would have taken at least 2 triaxle loads of topsoil. Soil improvement I've been working on, but it takes years and I'm more looking at what to do now and in the interim. I've planted perennial peanuts for example to put nitrogen back into the soil. I'm going to get a pallet of pine bark fines also.

I think what Silica said makes the most sense. I have been fertilizing regularly, but I'm just going to have to do it every 2 months. I know FL soil is generally bad, but its REALLY bad down here in SWFL. Pure beach sand, no organic material whatsoever.

Curiously, when I was doing the tests I noticed whenever there was a tiny particle of organic matter, the fertilizer was sticking to that, making a bright color change on that spec of organic matter.

BTW Silica, I've read just about every pub UF has put out that I can find. They're a really great resource, and I just dropped off my youngest kid there for his freshman summer session.
Silica
10 years ago
last modified: 10 years ago
bruce5881, you can get a 41 page booklet titled "Florida Your Dooryard Citrus Guide" from IFAS-Extension Bookstore, UF/IFAS Communication Services PO Box 110011, Gainesville, Florida, 3211-011. It covers the best recomended care for Florida home grown citrus trees. You can also call 352-392-2411. Good luck to you and your trees. - Silica
bruce5881
Original Author
10 years ago
Thanks Silica, I'll look into that booklet. I'll either have it shipped, or have my son pick it up for me.
pip313
10 years ago
last modified: 10 years ago
Consider rototilling the east side of the trees as deep as you can with wood mulch. Next year the west side. Year after that the north part that wasn't done as part of the east or west parts. The 4th year the south, the same only the part that wasn't done as part of the east or west.

or go two years in between if the trees are real large and you have to worry about stability.

If you can get organic matter into the soil do so. Otherwise yes fertilize often and use slow release so it doesn't just wash away.

the worms and stuff will carry the organic matter down a few extra inches to a few feet but will take quite a few years.