A freshly picked, vine-ripened tomato is hard to rival in the home garden. Tomatoes grow well and produce healthy fruit in larger quantities when grown in slightly acidic soil that is rich in organic matter and contains adequate amounts of calcium and magnesium. Using dolomite, also known as dolomitic lime, can help to adjust soil pH to the desired range for growing tomatoes. Dolomite also provides and facilitates the availability of soil nutrients to plant root
Dolomite consists primarily of calcium and magnesium, two minor nutrients essential for healthy tomatoes. It is generally obtained from pulverizing limestone. It is useful in the home garden as a soil pH adjuster when applied correctly. Tomato plants absorb the most nutrients from the soil when its pH falls within the desired range. Dolomite also increases magnesium levels in the soil. In areas with a known magnesium deficiency, this is crucial for growing healthy tomatoes.
Before planting a tomato garden, test your soil using a commercial kit or a service in your local area. Acidic soils benefit from incorporation of dolomite as early as possible before planting. Your soil test results will recommend lime amendments at a specific rate to increase soil alkalinity, if needed. Tomatoes prefer a soil pH of 6.5 to 6.8 for best growth and fruit production. Treating untested soil with dolomite is risky, especially if you garden in an area where soils are known to be somewhat alkaline.
Clay and silt soils are usually acidic. They are also considered "tight" in that they are often poor in organic content, leading to compaction and poor root oxygenation. Conversely, sandy soils can dry too quickly. The use of dolomite alone may not be enough to prepare these soils for growing tomatoes. Amending the soil by working in a 3- to 4-inch layer of organic matter such as compost or manure to a depth of 12 inches, along with dolomite, supports vigorous tomato root systems, healthier plants and increased fruit production.
Blossom-end rot is a common issue that frustrates many tomato growers. It typically occurs if the soil is calcium deficient or does not promote calcium transfer. This occurs most often in soils that are too acidic, especially those with a pH lower than 6. In some cases, calcium presence may be sufficient but tomato roots cannot absorb it if the environment is too acidic. In this case, dolomitic lime is often recommended as the best corrective measure.