What Kind of Soil Does a Tomato Need?

Texture

• Texture refers to the balance of silt, sand and clay in soil. Tomatoes brow best in deep loamy soils, which have a fairly even balance of these three elements. They do not fare well in soils with a lot of sand or clay. To improve sandy and clay-heavy soils, work in 2 or 3 inches of peat moss, compost or other organic matter to the top 8 inches of your soil. Organic matter also adds nutrients to the soil, providing a double benefit.

Moisture

• Tomatoes need lots of water to bear healthy fruit, but with water it's important to avoid giving your plants too much of a good thing. Wet, waterlogged soil can suffocate the roots of your plants, so avoid planting tomatoes in a location where standing water gathers after a rain. Once established, water them no more than is necessary to keep the soil moist.

pH

• The pH of soil refers to its acidity or alkalinity; a high pH means that your soil is alkaline, while a low pH means that it is acidic. A pH between 6.5 and 7.0 is roughly neutral, and this is the range in which tomatoes grow best. They will also tolerate slightly acidic soil. A soil test from your local university extension office will tell you the pH of your soil and make recommendations for altering it, if necessary. Lime is the most common amendment to raise pH, and sulfur is sometimes used to lower it.

Fertility

• Fertile soil is essential to growing a bountiful tomato crop. Incorporating organic matter into the soil before you plant will help with fertility, but you may also need to add commercial fertilizers, in some cases. Look for fertilizers with high levels of phosphorous. Nitrogen is also an important element, but avoid using nitrogen fertilizers excessively as this can lead to bushy plants with lots of leaves but very little fruit. The University of Rhode Island recommends adding a complete fertilizer, such as 5-10-10, 5-20-20 or 8-16-16, at a rate of 2.5 to 3 pounds per 100 square feet, about 2 weeks before planting.