At the risk of sounding stupid, I was curious if anyone knew the answer to this. I’ve been seeing Soy Hydrosolate based Amino acids for Nitrogen in organic farming for a hot minute. Now, I see Brandon Rust using his own product called Amino N+.
From what I can tell, it’s just soy protein powder?
Hydrolyzed vegetable protein (HVP) is produced by boiling foods such as soy, corn, or wheat in hydrochloric acid and then neutralizing the solution with sodium hydroxide or evaporating the acid off under vacuum. The acid breaks down the protein in vegetables into their component amino acids.
So basically, you take soy powder, boil it in HCl and then vacuum purge or neutralize. I bet getting that, or just buying HSP on eBay is the cheap route.
I tried two different application rates through a soil drench with soy protein powder. 1oz vs 3oz per gallon @6.4ph RO. These were applied to young vegging plants that were getting hungry before transplanting. I watered in and waited 5 days with no visible change in color.