Foliar Fertilization Chart

I would like to supplement some of my trees and vegetables with foliar feeding, especially peaches that have been damaged from severe PLC and citrus that are displaying iron chlorosis and nitrogen deficiency.

The literature that I reviewed on this topic gives fertilizer mixing rates for large acreage. However most of us need application rates for home orchard and gardens.

I have adapted the recommendations in this paper for use in either of a common 1 gallon or 3 gallon backpack sprayer.

I have no formal training in chemistry so I’d love to have someone check the chart before I start spraying my trees and veggies. Some concerns that I have are related to the chemistry and mixing ratio. For example if I am mixing nitrogen at .5 oz per gallon (per the chart) and it is labeled as a 34-0-0 fertilizer should I actually weigh out 1.5 oz per gallon since it is 34% nitrogen or does the remaining 66% also contain anything that can burn the plant? Same question for all other fertilizers.

Secondly, I ran across a note somewhere that said not to use ammonium calcium nitrate (15.5-0-0) as a foliar in combination with sulfates. Would this mean zinc sulfate monohydrate should not be used with it? I was intending to apply them in the same mix for tomatoes and other plants. Other than possibly forming precipitates when mixing, what is the problem with this combination?

Amount of fertilizers and water volume used in foliar spray of macro and micronutrients

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I cant speak to your numbers. Are you using a premixed formulation or trying to create your own? I spray a foliar fertilizer as needed, but mine is a product commercially sold and the field rep gave me the proper quantities to apply. Makes lif much simpler and the cost was pretty reasonable in my opinion.

I intend to create my own foliar mix from the following fertilizers that I have on hand:

Ammonium Nitrate (34-0-0)
Monopotasium Phosphate (0-52-34)
Zinc Sulfate Monohydrate
Ammonium Calcium Nitrate (15.5-0-0)
Magnesium Sulfate
Chelated Iron

This is a @Richard question. I am not a horticulturalist, but am a water chemist.

To me calcium phosphate stands to higher chance of precipitating than CaSO4, as the solubility of Ca-phosphate minerals are lower than gypsum (CaSO4). But phosphate solubility strongly depends on pH of the mixed solution, with Ca-PO4 being more insoluble at higher pH. Sulfate solubility is much less a function of pH because SO4(2-) dissociates completely at all pH’s that won’t acid-burn your plants. If Ca-PO4 precipitates it won’t be useful to your plants.

I put on a foliar app of a Miracle Gro product I had on hand to help my Redhaven peach tree get over the PLC it has. I believe most of the N came from urea in the Miracle Gro. I always think of ammonium being toxic in excess… not sure if that is the case for plants or not. So putting on ammonium instead of urea could cause a burning problem. But I honestly don’t know…

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If you are going to mix your own start out spraying a small area. There’s a high chance of burning the foliage, having it so weak it doesn’t help much, or who knows what.

I think you’d be better off using a soil application or a product like Miracle Grow that’s labeled for foliar. They’ve done the work for you.

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Dan, I don’t understand why you wish to mix your own foliar spray. For the total quantity you’ll use, a 3-lb jar of water soluble from a retail nursery should last one or two years.

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I have read that ammonium toxicity can sometimes be an issue in plants. Also the urea forms of nitrogen are generally safer for foliar application due to lower salt index.

That’s a good question Richard. I suppose the primary reason I’d like to learn to mix my own fertilizer is so that I can become a more competent gardener. Learning about plant chemistry and biology are facets of this hobby that I find very enjoyable.

Secondly I have expansion disease. This is a malady where I find my orchard and garden increasing exponentially in size every year. Buying fertilizers in small quantities from nurseries is quickly becoming fairly expensive, especially considering that I already have most of what I need already on hand.

Dan, to safely make water-soluble​ fertilizer you’ll need a few sensors to insure the aerosols above the mix aren’t approaching the flash point of combustion. Second, you’ll a dryer to dehydrate the mix into a soluble salt. Third, you’ll need some understanding of salt (water) chemistry so that elements you desire don’t precipitate out … and vis a vis. Fourth, you’ll need to source an inert buffer that will keep your mix from becoming hydrophilic.

Now if your annual needs for foliar are exceeding 3-lb size, then I’d recommend you start buying the 25-lb size from a nearby Ag supplier such as Crop Production Services.

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I am not interested in manufacturing fertilizer. The only mixing would involve a bag of fertilizer, surfactant, and water in a sprayer.

In the spreadsheet that I created, I am simply attempting to convert the recommendations of the paper “Foliar Fertilization of Crop Plants” from Kg per 500 liters of water to ounces per gallon for home use.

In my second post, I listed some of the water soluble fertilizers that l already have on hand which I think would be candidates for foliar spray.

Has anyone done a side by side comparison on foiliar spray benefits versus not foliar spraying, particularly using standard off the shelf item like general miracle grow or miracle grow for tomatoes. (these questions are actually more directly related to growing tomatoes than they are fruit trees for me)
Noticable difference?
Also is it redundant to do both roots and foiliar?
And one more question do you put a type of soap like dawn in with spray to overcome the natural oils on a leaf?
thanks!