Epsom Salts on Lawns: Myth vs. Reality

Why Epsom Salts Are Not a Lawn Fertilizer Substitute

A New England homeowner considers using Epsom salts (magnesium sulfate) instead of winter fertilizer, believing it provides slow-release nitrogen.

Scientific Reality

• Epsom salts supply magnesium, not nitrogen.
• Magnesium deficiency in lawns is extremely rare.
• Added magnesium leaches quickly from soil.
• Unnecessary fertilization wastes money and harms soil microbes.

Dr. Linda Chalker-Scott (WSU Extension) debunks the Epsom salts myth: don't add nutrients unless a soil test confirms deficiency. "Winterizing" fertilizer is a marketing gimmick. Best fall practice: mow shorter on final cut, leave leaves to decompose (if no chemicals used), and apply corn gluten meal next spring for weed suppression and slow-release nitrogen.