After searching around (and lots of false starts) I was finally able to find a local source (a turf center) for 00-00-50 sulfate of potash in 50 pound sacks - I don't remember the price, but it was in the $30-$40 range. It was produced by Kirby Agri, Lancaster, Pennsylvania. I don't need reagent quality for my plants! The people I talked to at the local garden centers just don't seem to understand the potash issue, and the labels on the bags are not our friends. Twice I ordered what was promised to be sulfate of potash, and what was delivered (and refused!) was muriate of potash. Jim McKenney