Gardeners often marvel over towering tomato plants in the garden. What many people do not know is that too much upward growth of the tomato plant can cause problems with the fruit. After the first month of growth, tomatoes can double their size every 12 to 15 days. The plant variety, weather conditions, soil and pruning all affect how tall the tomato plant will grow.
Choose a tomato plant that typically has limited growth upward. A determinate plant only grows to around 4 feet tall. Determinate varieties that have limited growth usually produce smaller fruit and all at once. Varieties include Early Girl and Early Cascade. Indeterminate tomato continue to grow in height until the season ends. Common varieties of indeterminate plants include Super-Steak, Brandywine, Beefsteak, Better Boy and Big Boy.
Prune the intermediate tomato plant regularly using a simple pruning technique. Find small shoots, typically called suckers, that need to be removed. Suckers can be found between the branches of the plant and the main stalk of the plant. Pinch off the suckers with your fingers. Do not use a shear for this process unless the sucker has been on the plant for awhile and is too thick to snap off.
Cut off the top of the tomato plant where you want it to stop growing. Use sharp clean pruning shears to make an even cut across the main stalk. This cut may seem harmful to the tomato plant, but when a plant is getting too tall, it is likely strong and healthy if it is reaching outrageous heights. Once the stalk is pruned to your desired height, regularly check for suckers that grow at the top. Pinch the suckers off.