Epsom Salts are part of the "Hooker" solution, and I used the modified Hooker ( without the insecticide) as a drench for daylilies and roses for many years. However, the fish emulsion, which is nasty, really NASTY smelling, attracted skunks that would try to dig up anything nearby in an attempt to find the fish, caused me to quit using this a few years ago. Several organic recipes from Jim Baker also use Epsom Salts. Soil testing is helpful as others have said.
