Plant Profile: Solanum lycopersicum

Tomatoes are a beloved choice among gardeners and rank as the most popular vegetable grown at home. These fruits come in a spectrum of colors, including yellow, red, and purple, and vary in size from small to large. Although they are botanically classified as fruits, their savory taste leads many to treat them as vegetables. Belonging to the nightshade family, tomatoes have been cultivated in North America for a considerable time, yet they are not indigenous to the region.

To thrive, tomatoes require fertile, well-drained soil, abundant sunlight, warmth, and ample water. They thrive best in slightly acidic soil with a pH between 5.5 and 7. Consistent watering is crucial to prevent issues like blossom end rot and fruit splitting. While tomatoes benefit from good nutrition, excessive fertilizer—particularly nitrogen—can result in lush foliage with minimal fruit yield. There are various cultivars: bush-type (determinate), semi-determinate, and vining (indeterminate). Bush-types are compact and produce a fixed amount of fruit, while vining varieties can grow several feet tall and yield fruit continuously until frost, with semi-determinate types falling in between. Although determinate cultivars may not always require support, it is advisable to cage them, as their stems are often weak and can sprawl on the ground if not staked. Cages can be installed during planting.

Tomatoes can be started indoors from seeds 5 to 6 weeks before the last frost or purchased as transplants. It’s best to plant them outdoors after the frost risk has passed, ensuring the plants are well-watered before transplanting and selecting a site where no other nightshade-family plants have been grown in the last 3 to 4 years. Early planting is essential, especially in North Carolina, where hot summers can cause blossoms to drop before fruit sets, making it particularly challenging to grow larger varieties like beefsteak tomatoes. Space the plants 18 to 24 inches apart. Tomatoes can develop additional roots along the buried portions of their stems; therefore, removing the lower leaves and planting the stem 2 to 3 inches below the soil can enhance root growth and overall plant health. Additionally, tomatoes can be successfully cultivated in containers that are at least 5 gallons in size and 1 to 2 feet deep, with one plant per pot.

However, growing tomatoes comes with its challenges. They are vulnerable to a range of pests and diseases, including blights, blossom end rot, wilts, and various bacterial and viral infections, as well as threats from tomato hornworms, aphids, beetles, and cutworms. Environmental factors and human errors, such as overhead watering, can also pose problems. Despite the effort required, the rewards of growing tomatoes are often well worth it.

Dr. Anna Dulaney, a Clinical Toxicologist and Assistant Director of Education at the Carolinas Poison Center, notes that since the database's inception in 1997, there has been only one recorded case of a child reacting to the consumption of tomato leaves or stems. In that instance, the child ingested a "pie" made from cedar wood chips, grass clippings, tomato leaves, and other materials, resulting in vomiting. However, due to the variety of ingredients involved, it is difficult to determine if the tomato leaves were the cause of the upset stomach. Dr. Dulaney also mentioned that the highest number of tomato leaves consumed at once was 5 or 6, with no adverse effects reported. (This footnote was added by Dr. Lucy Bradley, NC State Extension Urban Horticulture Specialist, on 10/26/2010.)