Jim: I have sought out Sulfate of Potash here in N. New Jersey after seeing Ian Young's glowing praise of it. I was convinced to substitute Muriate of Potash once but never again. I found the Sulfate of Potash and it was manufactured by Espoma. http://www.espoma.com/ I picked up something different last time and it was "Epsom Plus". Listed as 0-0-22, derived from Sulfate of Potash Magnesia. Arnold