P, why are you wanting just zinc and chelated iron? The thing about micronutrients, is they must be applied in a certain ratio. If you're going to start applying just certain micronutrients, I wouldn't recommend it unless you've had a good soil analysis done, and know for sure you're deficient in just these two micronutrients, I'd apply all micronutrients in their proper ratio. If you've done that - had a soil analysis completed, and know for sure these two minerals are deficient in your soil, I would try contacting your local orchard supply company. One that supports some of your commercial growers in the area. They should be able to get both chelated iron and zinc sulphate for you and help you with the correct application amounts. Citrus are very particular in their uptake of micronutrients, and do so in particular ratios. So, it's important that what you apply for micronutrients is balanced, or you can actually cause a lockout of other micronutrients. I know AZ, like parts of S. California can be deficient in iron, manganese and zinc. What was recommended to me by Vince Lazaneo, the head of our Master Gardener program in San Diego county was a foliar application of Grow More Citrus Growers Blend and use it as a foliar application. I know I have a manganese deficiency, but by applying all micronutrients together in proper ratios, I can guarantee they will be absorbed by the tree. Probably more than you actually wanted to know, lol!!

Patty S.

Hi Patty:

Thanks for the reply. In actuality, these were prescribed by my horticulturalist who recommended use of these based on an on the ground exam. What I should have made clear is that the zinc is really for my nut trees and grapes while the iron is for my citrus and pomegranates. No evidence of any manganese or other trace issues. Our soil here in Tucson is very iron deficient and alkaline (which means you have to buy the chelated iron for over 7 pH). Apparently the nuts/grapes require large amounts of zinc sulphate (over a pound twice per season) while the citrus and pomegranates take 2 Tbs per tree for now. I am going to apply now and see if this helps the issues identified. I only wish we had an orchard supply house locally. So, I purchased what I need now at my horticulturalist's place and will go online and search around for other for next year.

BTW, earlier this year I bought some powdered STEM foliar spray from somebody (either on this forum or on the Citrus Grower's forum) but I have lost the contents of what is actually in there. Google is no real help here. Any idea?

Thanks again,

Peter

Annoyingly it is difficult to get MSDSs or sometimes even the guaranteed analysis on JR Peter's products. You have to call them and ask them to email them to you. Here's the STEM from a post from Al awhile back:

GUARANTEED ANALYSIS
Sulfur (S) (Combined) .............................................................................................. 13.00%
Boron (B) .................................................................................................................... 1.35%
Copper (Cu) (Soluble) ................................................................................................ 2.30%
Iron (Fe) ...................................................................................................................... 7.50%
Manganese (Mn) (Total) ............................................................................................. 8.00%
8.00% water soluble manganese (Mn)
Molybdenum (Mo)...................................................................................................... 0.04%
Zinc (Zn) (Soluble) ..................................................................................................... 4.50%
Derived from: boric acid, copper sulfate, ferrous sulfate, manganese sulfate,
ammonium molybdate, zinc sulfate.

I don't believe that this is the ideal ratio of these micros according to Al's posts in other places but there you have it. He says he used to use the product so it can't be too far off. Also note there's no Ca or Mg in there.

When I made my homemade foliage pro I bought the micronutrients from JR Peter's Lab:

They have both products. They aren't the cheapest source but they are reputable. http://www.jrpeterslab.com/spec_chemicals.html

Thanks Redshirt!!

P.