Potassium additive

I'm not precisely sure where this will fit.

I am doing an almond shell ferment to create a potassium additive for plants. When I did it previously I used the same process I use to make vinegar. I was wondering if a lactobacillus ferment might work better for extracting the nutrients? Or would the salt cause problems later?

Well, you don't have to have salt.
Salt gives advantage to the lacto bac, but you can do without it, especially since you aren't going to eat the results.
Whey could help ot just a juiced cabbage.

I added a few tablespoons of milk, but I'm wondering if one process would have an advantage in the amount of potassium released.