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The Anatomy of Tomato Plants

By Barbara Gulin ; Updated September 21, 2017
Tomato plants are similar to many garden vegetables.

A tomato is a common vegetable in gardens. Knowing the anatomy of the tomato plant helps you communicate with gardening experts if you need help growing plants or diagnosing a problem. It also helps you make educated pruning and planting decisions. The primary components that make up a tomato plant are the root, stem, leaves and branches, flowers and fruit.

Parts of the Plant

A tomato's root system carries nutrients and moisture from the soil to the rest of the plant. Tomato plants can exhibit two different root structures, either taproot or fibrous, depending on whether the plant was generated from a seed or cutting from another plant. The main structure of the plant is the stem. Growing from the stem are the branches and leaves, where you will find flowers and fruit on mature plants. Determinate tomatoes will have multiple stems, while indeterminate, or "vining," tomatoes typically have one primary stem. Tomato flowers are yellow and about an inch in diameter when they are ready for fertilization.


Identifying the type of tomato plant (determinate or indeterminate) is simple. Determinate plants grow until they are about 4 feet tall. Their flowers and subsequent fruit are found at the end of the branches. Most of their fruit will mature within about a one-month span, then the plant dies. Indeterminate tomatoes will grow to a height of 6 feet or more, and they will continue to flower and produce fruit throughout the growing season. Healthy indeterminate plants stop producing when hard frost sets in.


Stems are the primary support for tomato plants. As indeterminate varieties grow, the weight of the plant and growing fruit can be too heavy for the stem. Providing additional support by staking or caging indeterminate varieties can increase fruit production. While many of the functions of the different parts of tomato plants are obvious, you may not realize that leaves perform different functions. Naturally, they are the primary sources for photosynthesis, converting sunlight to energy. As the plant matures and starts to produce fruit, leaves shelter growing tomatoes from excess sunlight. Tomatoes exposed to excessive sunlight are prone to sun scald. Avoid unnecessary pruning to protect your tomatoes.


When properly cared for, indeterminate tomato plants can grow to heights of 10 to 15 feet. Avoid pruning determinate plants as this can reduce fruit production. When you understand how the parts of the tomato plant work together to produce fruit, you're able to help them stay healthy and reduce the chance of spreading diseases like gray mold throughout your garden.


Knowing the anatomy of tomato plants can help you protect them from diseases and avoidable problems. Providing your plants what they need to sustain long-term growth and healthy fruit production helps to ensure the best harvest possible.


About the Author


Barbara Gulin has been a freelance writer and editor since 2008. She has helped write curriculum for Asian elementary students to learn Engish and has written extensive content for Themomsresource.com. Gulin studied electrical and computer engineering at the University of Missouri, Kansas City. She is also a licensed life and health insurance agent.