Tomatoes are a warm-season annual that grow best when the soil temperature is at least 55°F and the air temperature ranges between 65° and 90°F. Tomatoes require from 50 to more than 90 warm, frost-free days to reach harvest. Tomatoes are commonly grown from seedlings started indoors and transplanted into the garden. Start tomato seed indoors as early as 8 to 6 weeks before the average date of the last spring frost. Garden soil is usually warm enough for tomato transplants 2 to 3 weeks after the last frost. If an unexpected frost threatens, transplants must be covered and protected.
Description. The tomato is a tender subtropical perennial grown as annual. Tomatoes are weak stemmed with vining or sprawling habits depending upon the variety. Tomatoes have alternate lobed and toothed leaves. Yellow flowers grow in clusters either along stems or at the end of stems. Depending on the variety, fruits vary in size from marble-sized to apple-sized and in color from red to yellow to orange to white. Some tomatoes may be green or purple-black.
Tomatoes can be divided into two main groups according to growing habits: determinate and indeterminate.
• A determinate or bush tomato flowers at the end of its stalks. When the determinate tomato flowers it stops growing--usually at about three feet tall. Flowers then set fruit. Fruit grows and ripens usually all at once over a four- to six-week period. Determinate tomatoes often sprawl and do best with some support.
• An indeterminate or vine tomato produces a succession of flowers along its branching spurs; fruit forms from those blossoms. The end buds of indeterminate tomatoes do not set fruit like determinate tomatoes. Indeterminate tomatoes will grow almost indefinitely if not pruned or stopped by frost. Some can reach 14 feet tall or taller if the growing tips are not pinched back. Most indeterminate tomato varieties require staking or caging.
Tomato classifications. Tomatoes are further classified by the size and shape of their fruit: currant, cherry, plum, pear, heart-shaped, oblong, oblate, and round. Tomatoes are classified by their color: red, pink, orange, yellow, cream, white, green, purple to black, and zebra-striped multi-colors.
Tomatoes also can be classified by when they come to harvest: early season (from 40 to 60 days); midseason (60 to 80 days); and late season (80 or more days). Some tomatoes are picked green and ripened indoors.