Tomato

Tomato, Lycopersicum esculentum (syn. Solanum lycopersicum and Lycopersicon lycopersicum) is an herbaceous annual in the family Solanaceae grew for its edible fruit.

The plant can be erect with short stems or vine-like with long, spreading stems. The stems are covered in coarse hairs and the leaves are arranged spirally. The tomato plant produces yellow flowers, which can develop into a cyme of 3–12, and usually, a round fruit (berry) that is fleshy, smoothed skin and can be red, pink, purple, brown, orange, or yellow in color.

The tomato plant can grow 0.7–2 m (2.3–6.6 ft) in height and as an annual, is harvested after only one growing season.

Uses

Tomatoes grow very well in warm areas at temperatures between 21 and 24°C (69.8–75.2°F). They require deep, loamy, well-draining soil with a pH between 5.5 and 6.8. If soil drainage is a problem then tomatoes can be planted in a raised bed. Like all fruiting plants, tomatoes require full sun for most of the day.

Tomato varieties

Determinate (“bush”) tomatoes have been purposefully bred to grow vertically and remain relatively compact. The plant will stop growing once fruit begins developing on the terminal shoot and all the fruits ripen at around the same time. In contrast, indeterminate (“vining”) tomato varieties spread laterally and will continue to grow and produce fruit until frosts begin the Fall. Indeterminate varieties can produce fruit in all seasons and fruits will develop and ripen at different times. Heirloom tomatoes are generally open-pollinated varieties that have been conserved over many generations due to certain desirable characteristics such as flavor. Hybrid tomatoes are the product of cross-pollination between two parents with desirable characteristics such as high yield, early maturation, improved flavor, or resistance to certain diseases.

Sowing seeds

In most cases, tomato seeds should be started indoors 6–8 weeks before the last Spring frost. Seeds can be direct seeded in areas with a long growing season. Seeds should be sown in flats or cell trays using a sterile seedling mix. Plant seeds to a depth of 0.6 cm (1/4 in) and water lightly. If cells are being used, plant several seeds in each cell and thin to 1 seedling after germination. Position trays in a bright South facing window or under fluorescent lighting. The optimum soil temperature for germination is 21–32°C (70–90°F). A heat mat can be used to warm the flats if required. Seedlings should emerge within 6-14 days and after the seedlings have developed the first set of true leaves then they can be moved to a larger (3-4 in) pot and moved to a cooler temperature (16–21°C/60–70°F).

Transplanting

Tomato seedlings are ready to be transplanted once they are 15–25 cm (6–10 in) in height and have 3–5 true leaves assuming all danger of frost has passed. Beginning approximately 7-10 days before transplanting, plants should be set outside to harden off. The transplanting site should be prepared by working in a balanced fertilizer according to the guidelines on the product label. Transplants should be spaced 76–123 cm (30–48 in) apart with a between-row spacing of 123 cm (48 in). It is common practice to plant tomatoes in trenches on their side as tomato stems will sprout roots along their length when buried. Avoid over-fertilizing transplants, particularly with nitrogen, at this stage of growth as it will promote the growth of foliage rather than fruits. Water plants lightly at the base instead of overhead as wet foliage is more prone to diseases and the buried stem needs time to adapt and sprout roots. It is important that tomato plants receive even watering to prevent the development of blossom end rot, drip or soaker hoses work best, and mulching around the plants helps to conserve soil moisture.

Stakes, Cages, and Trellises

Staking, caging, or trellising tomatoes supports the plants and helps to keep fruit off of the ground as well as increasing air circulation around the foliage which helps to prevent disease. The type of support system used depends on the type of tomatoes being grown. Determinate tomatoes have short or medium-length vines and stop growing once fruit develops on the terminal branches. Determinants can be staked or caged but do not adapt to trellises. The position of the fruit means that little heavy pruning is required. In contrast, indeterminate tomatoes grow indefinitely and require a support system to prevent them from trailing along the ground. The amount of pruning required depends on the support system being utilized – vines require only light pruning when caged, moderate pruning when staked, and heavy pruning when using a trellis.