Seed catalogs abbreviate indeterminate tomato varieties as "Indet." Determinate varieties are noted as "Det." Determinates are also sometimes called "self-topping." Familiar determinate varieties are 'Celebrity,' 'Mountain Pride' and 'Rutgers.' Heirloom tomatoes are predominately indeterminate because they are not bred for specific qualities. Other familiar indeterminate tomatoes are 'Better Boy' and 'Big Beef.'
Indeterminate tomato plant growth continues until frost or another external factor stops it. Determinate tomato plants are hybridized for a particular growth structure. Growth stops at a predetermined height. Determinate tomatoes have short branches with flowers and fruits on the ends. Indeterminate plants blossom and set fruit all along the branches. They range from 6 to 8 feet tall.
Determinate tomato varieties grow bushy plants that produce a crop all at one time. They stop growing and producing fruit at a particular predetermined height. Commercial growers prefer this type and they are good as container plants for home gardens. Indeterminate varieties, known as cultivars, grow long, ranging branches and produce fruit continuously until frost. Heirloom tomatoes are indeterminate because they are not hybridized.
Indeterminate variety tomatoes are gaining in popularity as people discover heirloom tomatoes. Heirloom, or heritage, tomatoes are often disease-resistant and the seeds can be saved year to year. Heirloom tomatoes come in a wide range of colors, sizes and shapes. They are often more flavorful than hybrid, or determinate, varieties. Heirloom varieties such as 'Brandywine,' 'Cherokee Purple' and 'Green Zebra' are becoming more familiar at garden centers.
Plant determinate tomatoes 12 to 24 inches apart. Indeterminate varieties that are not staked should be planted 24 to 36 inches apart; staked varieties 14 to 20 inches apart. Staking and pruning indeterminate tomato plants can improve fruit production and shorten time to harvest by one week or more. Staking also improves fruit quality and makes harvest easier. Staking reduces the total tomato yield but fruit is larger. Allowing indeterminate varieties to sprawl reduces labor time but increases disease problems.
Consider the garden space you have to grow tomatoes in before you decide on determinate or indeterminate types. Tomato cages that are over 5 to 6 feet in height are useful for both types of plants. Some gardens are big enough to let indeterminate tomato plants sprawl on the ground and range beyond 8 feet. Determinate tomatoes do very well as patio container plants.