Tomatoes Solanum lycopersicum

Tomatoes are a garden favorite and the most popular homegrown vegetable. The fruits come in various colors from yellow to red to purple and size small to large.  Tomatoes are grown as an annual, but in frost-free climates, they are perennials. The plants can grow 3 to 10 feet tall and 1 to 4 feet wide. The plant usually has glandular hairs that are very "sticky." While the portion eaten is botanically a fruit, tomatoes are considered a vegetable due to their savory flavor. All green parts of the tomato plant are poisonous. They are in the Solanaceae or nightshade family which includes potatoes, eggplants, and peppers.

Tomatoes are native to Peru, but they have spread worldwide after the Spanish colonization. China is the largest tomato-producing country, followed by the United States, Turkey, India, and Italy.

The genus name, Solanum, is the Latin word, solamen, which means "comforting or soothing."  The species name, lycopersicum, means "wolf peach." Tomatoes were called "wolf peaches" when they came to Europe. This originated from a German legend that witches and sorcerers used the fruits in potions to turn themselves into werewolves. The word "tomato" originates from the Spanish word tomate. The French call the tomato. the pomme d'amour or 'Love Apple," because they believed it was an aphrodisiac.

Tomatoes need fertile well-drained garden soil, full sun, warmth, and moderate water. They prefer moist, loamy, and slightly acidic soil with a pH of 5.8 to 6.8. Keep the soil consistently watered to avoid blossom end rot and splitting fruit.  While they need decent nutrition, too much fertilizer, especially nitrogen, can lead to extensive leafy growth with little fruit production. They also prefer temperatures between 70 to 75 degrees Fahrenheit. The use of cages or staking the plants will keep the stems from breaking or drooping from the weight of the tomatoes.  The plants are reproduced by seeds and are best planted 2 to 3 feet apart and 1/4 inch deep. Harvesting of fruits may occur 2 to 3 months after planting the seeds or up to 4 to 5 months depending on the variety. 

The stems and the leaves of the tomato plant are densely hairy. The green leaves are 4 to 10 inches long with 5 to 9 leaflets and each leaflet is 3 inches long with serrated margins. The flowers are less than 1 inch in diameter, yellow, and have 5 lobes. They appear in clusters of 3 to 12 blooms. The tomato is the fruit and is classified as a berry. The average tomato weighs about 4 ounces. 

The leaves, stems, and green unripe fruits contain small amounts of toxin alkaloids known as tomatine and solanine. The tomato plants are toxic to dogs if a significant amount of the fruits or foliage are eaten. 

There are thousands of varieties and cultivars of tomatoes. They are commonly classified as determinate or indeterminate. 

• ​​​​​​Determinate: bush-type, bears a full crop of fruit all at once, grows to a specific height, and is good for container planting
• Indeterminate: vine-like, never top off, and continue producing fruits until frost

Planting: Tomatoes can be started by seed indoors 5-6 weeks before planting or bought as transplants.  Plant outdoors after the risk of frost has passed, water plants well before transplanting, and choose a location where other nightshade-family plants have not been grown within the past 3-4 years.  Plant as early as possible as North Carolina's hot summers can cause blossoms to drop before setting fruit.  Larger fruits like beefsteak tomatoes are harder to produce in NC for this reason.  Space plants 18-24 in apart.  Tomatoes will grow extra roots on portions of the stem that are under the soil; remove the lower set of leaves and bury the lower portion of the stem 2-3 in below the ground to increase root growth and plant vigor.  Tomatoes can also be grown in containers at a minimum of 5 gals and 1-2 ft deep, one plant per pot.

Tomatoes can be a lot of work, but the taste of a fresh tomato is hard to beat. To get started, you may want to consider a container, patio plants, or a small vegetable garden in your backyard. Tomatoes can be eaten fresh or frozen and canned for future use for making sauces, soups, or salsas. 

Seasons of interest:

Bloom: Summer and Fall           Fruits:  Summer and Fall  

Quick ID Hints:

• erect or ascending with light to dark green tender stems with sticky dense hairs
• alternate, densely hairy green compound leaves, 4 to 10 inches long with 5 to 9 leaflets, each leaflet 3 inches long with serrated margins
• small yellow star-shaped, five-lobed flowers
• the berry fruit is the tomato varying size, shape, and color depending on the variety or cultivar

Insects, Diseases, and Other Plant Problems:  Tomatoes are susceptible to many pests including stink bugs, cutworms, tomato hornworms, tobacco hornworms, aphids, cabbage looper, whiteflies, tomato fruit worms, flea beetles, red spider mites, slugs, and the Colorado potato beetle.

Diseases include blights, blossom end-rot, Verticillium wilt, Fusarium wilt, Tobacco mosaic virus, and bacterial and viral diseases. Cultivars can vary in their disease resistance. Many hybrids have been developed to improve disease resistance.

Cracking of the tomato fruit can occur due to uneven watering or uneven moisture from weather conditions. 

Additional Toxicology:  According to Dr. Anna Dulaney, Clinical Toxicologist and Assistant Director of Education for the Carolinas Poison Center, since their database began in 1997 there has been only one reference to a child having a reaction related to consuming tomato leaves or stems.  In that instance, the child made and consumed a "Pie" consisting of cedar wood chips, grass clippings, tomato leaves, and various other items.  That child vomited, but due to a large number of ingredients in the mixture, it is impossible to attribute the upset stomach to the consumption of tomato leaves.  She noted that in their database, the largest number of tomato leaves consumed at one time was 5 or 6 and that there were no ill effects. (This footnote inserted by Dr. Lucy Bradley, NC State Extension Urban Horticulture Specialist 10/26/2010)