Magnesium Sulfate is used to correct magnesium deficiency in soil (magnesium is an essential element in the chlorophyll molecule). Magnesium Sulfate is most commonly applied to potted plants, or to magnesium-hungry crops, such as potatoes, roses, and tomatoes. The advantage of magnesium sulfate over other magnesium soil amendments (such as dolomitic lime) is its high solubility. Magnesium Sulfate contains a soluble source of magnesium that is readily available to aid in correcting plant chlorosis. Excellent for use on palms. Also can be used to encourage white blooms on hydrangeas.