How to Slow Tomato Growth

Test your soil before planting tomatoes to determine the nutrient levels in the soil. You can purchase a soil test kit at the hardware store for a few dollars. Although the home soil test kit is not as thorough as soil-testing services, it provides you with the information you need to balance basic nutrients in the soil.

Follow the instructions in the kit for balancing nutrients. When nitrogen levels are too high, tomatoes grow rapidly producing large, bushy plants, but do not produce abundant fruit. Balanced nutrients are key to healthy growth and abundant fruiting.

Apply fertilizer designed for tomatoes following the recommends on the product. These formulas, available as water-soluble mixes or granular formulas, contain the right balance of nutrients for tomatoes. Other fertilizers may be too high in nitrogen for your tomatoes.

Withhold fertilizer if your tomatoes show rapid growth, large leaves and deep green coloring early in the season. Although this is a sign of excess nitrogen in the soil, it may normalize during the season if you withhold any future fertilizer.

Flush the soil of container-grown tomatoes with plenty of water, allowing the water to run freely from the bottom of the container. This sometimes works to leach nutrients from the soil and may rid the soil of excess nitrogen. Although the process can technically be completed with any soil, unless your soil is sandy and drains easily, it is not practical for plants grown in the garden.

Avoid adding manure or compost to the soil as they provide slow-release nitrogen. Both are beneficial for amending the soil in the spring, as they increase aeration and improve drainage, but if growth is excessive -- or has been in previous years -- withhold sources of nitrogen.