I’m starting to experiment with chelating manganese sulfate and copper sulfate. So I’m looking for info and came across this thread. I have a few comments and questions…

1. is there a agronomic chelation handbook out there somewhere?
2. Here’s what I’m testing. Agrothrive 3-5-5 is a complete organic fertilizer slurry made from anaerobic digestion of agricultural “waste”. The pH is about 3.5 and is dominated by lactic acid. I’m adding manganese sulfate and copper sulfate to the slurry, and adding extra citric acid just to cover all bases. I have no idea if adding citric acid is helpful, unnecessary or detrimental. I have no idea how well it needs to be mixed or how long it should sit to complete the chelation process. Any feedback on this concept is appreciated!
3. calcium acetate works well for foliar applications. I would put limestone (or eggshells or seashells) in a 5 gal bucket of 5% vinegar, wait a week to mostly neutralize. (You can’t wait a week, so I would just always have a bucket sitting with this, for whenever needed). By my memory that would give me about 10,000ppm Ca. I would dilute it to 1000ppm Ca, add yucca extract for wetting. Depending on how long the vinegar solution sit, the pH could be anywhere from 4-7. More time = higher pH. For compatibility issues in my foliar applications, I try to spray most things at pH 7. So I test the pH calcium acetate solution and then I add RO reject water to the solution until the pH hits 7 (you can use probably any pH UP, calcium hydroxide or potassium hydroxide). Our municipal water has about 150ppm carbonates, our efficient RO system (50/50) produces reject water at about 250ppm CO3 (I don’t know how this math works out, but it is what happens), most of the carbonates are calcium carbonate. The final solution is probably about 80% calcium acetate and 20% calcium carbonate. That’s what our plants get sprayed with and it solves all calcium deficiencies quite well. I’m guessing this whole process would work just as well with citric acid solution.
4. Are there any studies out there that suggest calcium acetate or calcium citrate perform better than the other?
5. The best calcium foliar spray that we use is a Wood Ash Solution. The downside is it has a pH of 9 and is not compatible with with many other foliar applications. But hey! Milstop has a pH 9 too and everyone seems to be fine with it. Wood Ash Solution is WAY better than Milstop, btw. 2 years of application to back that up. I try to make sure we don’t spray anything within a few days of Wood Ash foliar spray….so that’s the downside. Here’s the recipe: 2-4 teaspoons of wood ash** per gallon of water, mix for 5 minutes, or let sit for a 1 day. filter with 50 micron bag so it doesn’t clog your sprayer. add yucca extract for wetting. **4 teaspoons from wood ash from small open fire (low temp fire). 2 teaspoons from high temp fire (efficient wood furnace). Higher temps – more hydroxides. Lower temps = more carbonates. Hydroxides are more alkaline and more soluble therefore you need less wood ash. I prefer low temp wood ash because you’ll get a better balance of K/Ca, because calcium carbonate is not soluble, but potassium carbonate is. However, if you already have high K in your sap, then go with high temp wood ash. I think this works way better than Milstop because it contains a lot of trace minerals while still have a big dose of Ca and/or K.
6. you can test the calcium levels of your DIY foliar applications with API Ca test for aquariums. Take your approx 1000ppm solution, dilute 1 part solution in 9 parts RO/distilled/rain water, run the API test kit, multiply level by 10.

• This reply was modified 1 year, 4 months ago by  Benny Thompson.