Indeterminate tomatoes are often called “vining” or “climbing” types, and their growth habit is a significant departure from the more common bush varieties. This growth pattern means the plant does not stop growing once it begins to flower and set fruit. Indeterminate varieties continue to lengthen, produce new leaves, and set new flower clusters until a change in the environment, such as the first hard frost, brings their season to an end. Understanding this continuous growth is the primary consideration for planning your garden space and providing the proper support.
Understanding Indeterminate Growth
The tall stature of indeterminate tomatoes lies in the plant’s genetics, specifically the lack of the SELF-PRUNING (SP) gene mutation found in determinate types. Determinate varieties have a terminal flower cluster, meaning their main stem and side shoots end in a flower truss, which halts further vertical growth.
Indeterminate plants, however, maintain an active growing point, known as the apical meristem, at the tip of the main stem. This allows the plant to repeatedly generate new vegetative growth followed by a flower truss, with this pattern continuing indefinitely. The vine continuously extends its main stem and side shoots, known as suckers, throughout the growing season.
Typical Height Range and Potential
The typical height of an indeterminate tomato plant in a standard growing season ranges between 6 and 10 feet (1.8 to 3 meters). This range represents what most gardeners can expect from common indeterminate varieties like ‘Beefsteak,’ ‘Brandywine,’ or ‘Sungold’ cherry tomatoes, unlike determinate types which usually top out around 3 to 4 feet.
Under ideal conditions, such as in a greenhouse or in a warm climate with a very long growing season, the potential height is far greater. Some indeterminate varieties have been recorded reaching heights of 12 to 15 feet. The tallest documented tomato plants have reached over 65 feet (nearly 20 meters) in tropical or controlled environments.
Environmental Factors That Influence Size
While the plant’s genetics set the potential for unlimited growth, environmental factors determine its actual size by influencing the growth rate. Adequate sunlight is a major factor; plants that receive less than the optimal six to eight hours of direct sun will stretch to seek light, resulting in a taller but weaker, or “leggier,” vine. This stretching, known as etiolation, makes the plant susceptible to wind damage.
Soil fertility also plays a role, particularly the balance of nitrogen. Too much nitrogen encourages the plant to produce lush, tall foliage at the expense of fruit production, creating a dense, tall vine that may not yield well. Temperature impacts the overall length of the growing season, which directly correlates to the final height, since growth stops when the first frost arrives.
Necessary Support and Height Management
Because of their vining nature and continuous growth, indeterminate tomatoes require a robust support system installed at the time of planting to prevent the heavy, fruit-laden vines from sprawling on the ground. Short, store-bought cages are usually insufficient, and support structures need to be at least 6 to 8 feet tall.
Common support methods include tall stakes, such as metal T-posts or sturdy wooden poles, which require the main stem to be tied loosely to the support as it grows. Trellis systems, such as the “Florida weave” or overhead wire systems, are effective for rows of plants and help distribute the plant’s heavy weight.
To manage the vine’s final height late in the season, gardeners can “top” the plant by cutting the main growing tip above a flower cluster a few weeks before the anticipated first frost. This action redirects the plant’s energy into ripening existing fruit rather than producing new growth.