Dolomite is a limestone compound that contains calcium and magnesium. The best mixtures contain 8 to 12 percent magnesium and 18 to 22 percent calcium. These elements help influence the pH of the soil and provide valuable nutrients to plants. Dolomite can often contain sodium, but it should only be 0.2 percent sodium or less. More sodium can change the salinity of your soil, which can kill many plants.

Why Use Dolomite

Dolomite is best used to change the acidity, or pH, of the soil. Start with a soil pH test, which you can buy at garden centers, to determine the existing pH. Most plants do best with a pH of 6.0 to 7.4. If your soil registers with a pH of 5.9 or below, dolomitic lime can help raise the pH to make the soil more plant-friendly. Some plants prefer acidic soils, where the pH is lower, so check on your specific plants' needs before adding the dolomite. Some plants, especially vegetables that have lots of seeds inside, such as tomatoes (Lycopersicon esculentum), need extra calcium as they grow.