Calling all soil chemistry gurus!

7 years ago

I honestly thought I could cruise through gardening with a remedial understanding of NPK and pH. Oh how naive. My floundering young persimmon tree has forced me back into high school chem and the periodic table (FYI I made a C in that class). I have Mg, Ca, B, Zn, Mn, Fe and Cu problems, not to mention a very high pH (we have alkaline water). I'm attaching my lab tested results. They are abysmal and a comment on another site even questioned their validity. My 2 year old persimmon has chlorosis. We've had a long wet winter and spring here in SoCal (zone 10b). I have not fertilized this tree since planting in ground, and used plain bagged soil to fill the 4x4 raised box dedicated to the tree (dug 3' down, and combined it with the native sandy soil). I've sprayed it twice in the last 2 weeks with iron chelate and it seems to help a bit. I was told sulfer or copper sulfate for the soil but nothing specific beyond that. Should I include other elements to the spray to keep it healthy immediately, and what do I do to address it long term? Feeling pretty lost here!

Featured Answer

dchall_san_antonio

7 years ago

glib said, "Organic matter mitigates all that, I would mulch and spray, and wait for the mulch to trickle down."

I used to think that, too, until I read more. The microbes cannot thrive in a toxic environment. If the soil chemistry is toxic to the microbes due to an imbalance of salts, for example, simple balancing the salt structure can bring the soil back to life. The microbes might be able to do that over the next 50 years, or you can do that in the next 20 minutes once you know what chemicals are needed. Where is the result for sodium in the soil?

Here in Texas about 20 years ago the state was looking for someone able to reclaim plots of land ruined by brine water used in oil drilling. Most of the companies resorted to replacing the soil, but one company used a holistic (for lack of a better word) approach. They did the soil test, determined what the contaminants were, and put together a salt balance regimen followed by a few tons of compost. The process worked so well that plants grew up much taller than the surrounding area.

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Comments (7)

glib
7 years ago
Organic matter mitigates all that, I would mulch and spray, and wait for the mulch to trickle down.
toxcrusadr
7 years ago
Iron is not that bad, it says 'adequate.' Copper is low but I can't imagine it's causing the entire tree to be unhealthy.

pH is a little high but not really that bad. I have persimmons (wild American, not sure what you have) growing in neutral pH soil and they do fine. If you want to lower it a bit, you can add sulfur, but it does take some time to act. The soluble iron chelate products are often acidic as well, you can water with a dilute solution and take care of two issues at once.

The fert. they are recommending is just nitrogen. You might consider soluble plant food, if you can find one with hardly any P and K. Or get some granular urea, or high N lawn food (which is what the recommended product is).

Having said all that, most likely wet and/or cool weather is causing the chlorosis.lanted some tomatoes too early this spring, the soil and air temps were cool esp. at night and they looked terrible. Yellowish leaves and purple veins. Others planted 2 wks later look 500% better and are 5x as big already. Hang in there.
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RosyHips
Original Author
7 years ago
toxcrusadr, thanks for the advice to be patient. It's a Fuyu, my husband's special pick for the garden. He's pressuring me to keep it healthy since its loss would be a costly mistake.
Jean
7 years ago
I had a Fuyu and a Hachiya in Long Beach, CA. both planted in the ground. Never had micro problems. Mulched and not fertilized

Can you move yours to the ground?
RosyHips
Original Author
7 years ago
last modified: 7 years ago
Correction, I'm in zone 10a

Jean, the tree is technically "in ground", elevated from the yard level about 1 foot. This was recommended by the grower that sold us the tree. The "soil" I have here in the foothills isn't really soil, it's more like hard packed sand. I assumed plain bagged soil would be far better than what I have but apparently not. Wherever it came from, or whatever it's composed of, gave me those lab results (assuming the results are correct).

Update: the tree dropped tons of young fruit yesterday, and some leaves are turning black.
kokopellifivea
7 years ago
last modified: 7 years ago
Fixing a copper deficiency is easy enough; spray the affected area a couple of times with copper fungicide soap, according to the directions. It even counts as organic.

you can also put 3-5 grams copper sulfate dissolved in a five galLon bucket of water and use it as a drench. Note I said grams, not ounces.

Iron Sulfate always seemed a little rough to me. I like to apply in winter for that reason. Chelated iron works well if you don’t mind the expense.