P is mainly manure I believe. It is residual in rocks but I don't know if plants can use that. Ash is a good source for K if there are no other K-rich fermente

P is mainly manure I believe. It is residual in rocks but I don't know if plants can use that. Ash is a good source for K if there are no other K-rich fermented dead plants available. You get a lot of both from coffee grounds so someone might have to drink a lot of coffee.