Epsom salt (magnesium sulfate) is used in gardening to provide essential magnesium and sulfur, boosting chlorophyll production, making leaves greener, enhancing nutrient uptake (like nitrogen & phosphorus), and improving blooms/fruits for plants like roses, peppers, tomatoes, and citrus. It helps seeds germinate, deters pests (slugs, voles), and can correct deficiencies, often applied as a foliar spray (1 tbsp/gallon water) or worked into soil around the root zone.