Citrus iron deficiency or something else?

General Fruit Growing
#1

My 2 year old Calamansi tree is showing signs of iron deficiency, but it doesn’t make sense. Could it be something else?

The leaves look just like here for iron deficiency: HS-797/CH142: A Guide to Citrus Nutritional Deficiency and Toxicity Identification

However, I also have a meyer lemon and rangpur lime grown under identical conditions in 5 gallon pots. Nov through April they are indoors under LED light and get fed weekly with a 4x diluted solution of Jacks Classic No.1.5 20-10-20 Citrus Food Fertilizer. Outside in the summer they get big scoop of organic 5-5-5 fertilizer and worm castings. pH = 6 in all three.

How can one citrus be showing signs of Iron deficiency in same growing conditions as two others that don’t? Despite the leaf appearance, they tree looks otherwise healthy, had a productive winter, put out good growth in late spring, and is about to flower.

I have been applying chelated iron foliar spray every other day and put down some azomite granules in the soil about 10 days ago and haven’t seen any improvement yet. How long should it take assuming correct diagnosis? Should I do anything else?

Thanks all.

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#2

In my opinion:
Looks like mild Potassium toxicity, combined with poor root aeration.
Mycorrhizae & wild soil yeasts in poorly aerated soil can precipitate Copper.
Copper is part of the enzyme which turn Chelated Iron into Iron-Ligand & transport the ligands to the leaves.
Without these Copper enzymes plants can’t assimilate Iron!
The soil might actually be rich in Copper, it is just precipitated.
Mycorrhizae & yeast turn sugar into Ethyl Alcohol & Ethyl Alcohol precipitates copper.
If soil is aerated then acids get made from Ethyl Alcohol & excess alcohol evaporates from the soil rather than being trapped.
Citric acid can help dissolve all the micronutrients as well has act as a precursor chelate to producing ligands of all micronutrients.
Lemon juice works if you don’t have Citric Acid itself.
Put aeration holes in soil & water from the bottom.

Also:

Both too much as well as too little Copper can cause Iron deficiency see:

Potting soil is usually copper deficient, poor aeration makes it worse.
Organic fertilizer containing sugar or starch in poor aeration soil makes it even worse than that.
I the future use sand & perlite in the mix & water from the bottom or at root perimeter.

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#3

Too much standing water could definitely be the culprit as @ZinHead mentioned.

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#4

Before you start pouring anything to the soil, pull the plant out of the pot and look for root rot (bad smell, brown roots that break easily).

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#5

A good idea.
Rinsing roots in 1 teaspoon of Citric acid (3.2pH) per gallon of water is a good idea.
This is equivalent to lemon juice & will remove most invasive diseases without damaging symbiotic microbe relationships.
Then plant in something larger like a cloth potting bag with lots of sand, vermiculite, perlite, native soil, gypsum mixed into the potting soil.
Gypsum 7.4pH improves breathing as well as providing Sulfur & Calcium.

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#6

Thank you all for your expertise!

@disc4tw @Vlad - I have been using a cactus/citrus soil blend that drains really well so don’t think its an issue. To be sure, I did lift it out and roots look healthy creamy/yellow and takes up about 60% of the pot volume.

@ZinHead - I ordered citric acid. Do you still recommend adding despite absence of root rot? what concentration and frequency? Anything else in terms of micronutrients or conditioners in ! setting of good aeration already?

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#7

@bigiggye Your roots look fine but your mix looks very water retentive. Commercial cactus/citrus mixes generally are too water retentive. If you are not having root rot, you will later. I suggest you use a 5:1:1 mix, which is what many people use. (5 parts pine bark:1 part Perlite: 1 part peat moss.) Or Al Tapla’s gritty mix.

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#8

Yep, because Citric Acid helps chelate micronutrients.
I just read the SDS ingredients safety data sheet on the fertilizer:
Monoammonium Phosphate
Potassium Nitrate
Monopotassium Phosphate
Magnesium Sulfate
Boric Acid
Copper EDTA
Manganese EDTA
Iron EDTA
Zinc EDTA
Ammonium Heptamolybdate
My analysis:
Monopotassium Phosphate precipitates (Iron EDTA) into Iron Phosphate which is not water soluble.
Magnesium Sulfate will unchelate poor quality Iron chelates like Iron EDTA into Ferric Oxide which is not very water soluble.
Epsom salt increases the need for Iron too.
Increases in (Copper, Zinc & Manganese) combined with high Potassium at a time when Iron is being precipitated is the problem.
Answer:
1 teaspoon Citric Acid
1oz Gypsum
(1/4) teaspoon of Iron-EDDHA which won’t precipitate!!!

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#9

Always use Iron-EDDHA as the iron source!
20220617_200527

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#10

Re-Read your original statement again.
Azomite has very different results on different varietals & species.
It varies in pH from (8.0pH to 8.5pH)
This reduces Iron availability especially with Iron EDTA.
It also has a lot of water soluble Aluminum & water soluble Silicates.
It can cause Aluminum (& or) Silicone toxicity!!!
Discontinue.
What type of Iron foliar???
Citrus have very water tight leaves which don’t absorb foliar sprays well, especially when Potassium is high.
As that makes leaves smooth, glossy & water tight.
Iron-EDDHA can be sprayed on branches & nodes, plus put in the soil.
Spraying leaves doesn’t work well on Citrus.

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#11

Wow, thanks @ZinHead, I am blown away by your knowledge and grateful that you’re taking the time to share. Do you have a chemistry/agricultural science background? I am confused why the company would formulate such a fertilizer mix if half the salts precipitate out, and why this only seems to be a problem for 1 out of 3 trees with identical rootstock.

The iron I have is HEDTA, and since pH is around 6, it looks like only half is bioavailable, so I plan on doubling the rate you recommend. Have the citric acid and gypsum coming tomorrow.

Thanks again.

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#12

My career was as Environmental Services Director for hospitals, Nursing homes, school districts, military base etc.
My OCD hobby has been agronomy research & plant breeding.
So I have extensive topic knowledge in chemicals, microbes, photosynthesis, symbiosis, quorum sensing, pathology, etc.
I’m far from an expert in any one topic as I’m self educated.
However, I have far better understanding out how different things interact.
I generally use a computer to scan scientific research articles for key words & then only read what is relevant to my interests.
I highly recommend Iron-EDDHA.
Also you can mix (1/4) teaspoon per gallon of Glycerin into the solution with the Iron-EDDHA.
It will help the solution enter plant cells.
Even though Glycerin is a 100% natural organic plant based product, do not go over (1/4) teaspoon.
It increases the water solubility of Boron & Auxin.
Too much can causes imbalances in nutrient & hormones.
And always best to spray branches!
Most fertilizer products are messed up in one way or another.
It is the rule, rather than the exception unfortunately.

#13

Feel free to tag me on other topics.
Even if I don’t know the answer, I usually know who would know the answer.
I make it my top priority to have good mentors!!!
A pleasure to have been able to help.

#14

Thanks Vlad, I want to follow your advice but have some follow up questions. There are tons of different types of pine bark products - do you mean something like this?

https://www.homedepot.com/p/The-Bonsai-Supply-1-4-in-Particle-Size-2-qt-Pine-Bark-Fines-for-Bonsai-Orchids-Succulents-Cactus-and-Other-Potted-Plant-Soil-Mixes-Pine-Bark-2-QT/319248556

Do you think it’s worth repotting now, with better draining soil - I did repot it with additional perlite after pulling the plant out to take the picture a few days ago. I don’t want to keep disturbing the roots, and maybe giving time for the citric acid/gypsum/iron to work like Zinhead suggested. Alternativelty, I can wait till the fall as we are getting into the dry season here in Ohio, and I can ensure soil properly dries out before watering again.

Does pine bark do something that perlite doesn’t?

Thanks

#15

The Home Depot pine bark is fine, but expensive. I get my pine bark (fines) mulch from Agway. This is what it looks like:
image
I sieve it through a 1/4 inch screen.
I would wait one month before repotting to let it recover. Do not wait until the fall because you want it to be still in growth mode.
Pine bark fines retain more water than Perlite.

#16

@bigiggye your soil analysis indicates:
Magnesium, Copper & Iron levels very high.
Phosphate & Boron is low.
The fertilizer you used is high in:
Copper, Magnesium, Sulfate & Potassium.
All 4 of which if too concentrated interfere with Iron assimilation.
While your native soil is the correct pH,
Ohio water is 8.5pH to 9.0pH which keeps Iron in a Ferric Oxide state which is not very water soluble.
The correct procedure is:
MonoCalciumPhosphate aka TripleSuperPhosphate to counter act Magnesium, Potassium & Copper.
Gypsum 7.4pH to supply Calcium
Iron-EDDHA to have water soluble Iron.
Borax Glycerinate drop per gallon as foliar to improve Calcium & Iron assimilation.
This will correct the problem faster than anything else.
Far faster than organic material.
Yet will only be effective on new leaves.
Old leaves have too much (Magnesium, Copper & Potassium) combined Calcium deficiency.
So no matter how much Iron the plant gets those leaves can’t achieve good health.
Only new leaves will exhibit balance.
Calcium can only be assimilated by stem cells & juvenile cells.

#17

@ZinHead You said “your soil analysis indicates”. What soil analysis? I could not find the poster’s soil analysis. Please show me it.

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#18

@Vlad
I’m not going to post what another member sent me in a private email.
If @bigiggye wants to post his soil analysis or email you it, then he can.
Or he can give me permission to post the portion where I highlighted the Magnesium & Copper levels.

#19

Yes, since zinhead appeared to know a lot about soil chemistry, I sent him a private follow up question regarding a soil analysis of my backyard orchard, which is unrelated to the potted citrus in this thread. I am waiting to see if the citric acid, gypsym and iron do anything.

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#20

@bigiggye
If (Magnesium & Copper) are high in the soil,
there are most likely high in the City water supply too!
So please don’t assume that they are unrelated.
Your fertilizer which you claimed to have given the citrus was also high in Magnesium Sulfate, Potassium Sulfate & Copper.
Too much Sulfate also interferes with Iron assimilation in citrus.
I’m on 2 separate post threads here where Sulfate is involved in Iron deficiency.
It’s not a coincidence!