I've heard a lot about vinegar, mostly for getting rid of weeds but am a little nervous to try it. And I have the impression that hydrogen peroxide is such an ephemeral thing - the effects dissapate quickly? I have added coffee grounds to the bed I had tested but it's still registering at 7.1 pH. Garden sulfur would probably work to free up the Ca and Mg but not sure how much it would help with the other elemental shortages. I am using Borax to bring up the boron levels.
