Can I use Epson Salt as Fertilizer on my Centipede Grass or my St. Augustine Grass?
Will the Epson Salt kill the grass the way some fertilizers do.
Epsom salt is Magnesium sulfate. The only reason you should use it alone as a fertilizer is if a soil test has shown your soil to be deficient in Magnesium and Sulfur. If you are just guessing, then you could throw the mineral balance off and cause problems. And yes, MgSO4 can burn if used in excess, but not likely if it is prescribed in a blend of recommended fertilizer products to correct known deficiencies.
Soil analysis and Rx mineral amendments is the best way to go. But most people use general purpose lawn fertilizer that is rich in Nitrogen, Phosphorus and Potassim (NPK) and other nutrients, of which Magnesium can be one. The more complete and scientifically balanced the better.
But to use Epsom salts alone just because you have some may not be a good idea.