Why and how you should add Epsom salt to your garden.

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Q. "Why and how should I add Epsom salt to my garden?" is a question I'm frequently asked.

A. Epsom salt is magnesium sulfate. Magnesium is important for producing chlorophyll and fruit. It also strengthens cell walls and improves plants' absorption of vital nutrients such as sulfur, nitrogen and phosphorus.

Sulfur is vital to plant growth. It helps plants produce enzymes, vitamins and amino acids.

Magnesium deficiency may be difficult to detect without taking a soil sample. Some plants such as roses, tomatoes and peppers exhibit deficiencies more readily than others. Common symptoms include yellowed or misshapen leaves and stunting.

Magnesium is often deficient in soils with alkaline pH, high potassium and calcium content. Take a soil sample to your regional Cooperative Extension Service for testing. It's the best way to determine whether your soil needs magnesium. If the test shows severe magnesium deficiency, the service may recommend addition of dolomite lime to the soil. But don't rely on dolomite lime alone to correct the problem. Add Epsom salt, too. If the soil test shows adequate magnesium along with high potassium and calcium content, you should still add Epsom salt to your garden.

Epsom salt has the advantage over other sources of magnesium because it is highly soluble. The salt granules can be sprinkled around plants. Diluted with water, the Epsom salt solution can be poured around plants or sprayed on their leaves. The foliar spray delivers maximum rapid results.

How much Epsom salt you should apply depends on the size of the plant and the method of application. Vegetables such as tomatoes and peppers benefit from 1 tablespoon of Epsom salt granules at planting time. Sprinkle the granules around the transplants. Larger plants such as roses and shrubs will benefit from 1/2 cup of granules applied in spring and again in fall. Depending on plant size, apply 1/2 cup to 1 cup of granules around grape vines, fruit and nut trees at the drip line because that's where the feeder roots are. The drip line is the outer circumference of the leaf canopy.

For foliar spray, add 1 tablespoon of Epsom salt per gallon of water. Apply generously two or three times during the growing season.

Gardeners often report better plant color, stronger growth, improved fruit set, better tasting fruits and vegetables. Epsom salt applied to tomatoes may help to prevent blossom-end rot.

Epsom salt can be purchased at grocery and drug stores.

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