Indeterminate tomatoes are vining varieties that continue to grow, flower, and produce fruit until the first hard frost, often reaching heights of six to eight feet or more. This continuous growth habit means the plant will rapidly become an unmanageable tangle without structural support. Trellising is necessary to manage this vigorous growth, leading to a healthier plant and a significantly larger harvest. Providing a vertical structure maximizes yield and makes the fruit easier to access.
Why Supporting Indeterminate Tomatoes Is Necessary
Keeping the sprawling vines off the ground is crucial for preventing the spread of diseases. When leaves and stems contact wet soil, water splash can transfer soil-borne pathogens, such as fungal spores, directly onto the foliage. Trellising minimizes this contact, reducing the plant’s disease pressure and lengthening its productive life.
Vertical growth also promotes better air circulation throughout the plant canopy. Improved airflow helps leaves dry quickly after rain or watering, inhibiting the development and spread of fungal diseases. Supporting the plant vertically maximizes garden space, allowing for higher planting density, and ensures that ripening fruit does not suffer from ground rot, sunscald, or pest damage.
Choosing the Right Trellising System
The best support system depends on the gardener’s space, budget, and willingness to prune the plant. The Single-Stake method uses a tall, sturdy post, like an eight-foot T-post or rebar, driven deep into the ground next to the main stem. This method is best suited for plants that are aggressively pruned to maintain only one or two main vertical stems, directing the plant’s energy into producing fewer, but larger, tomatoes.
Heavy-duty welded wire cages offer a more hands-off approach, accommodating plants that are minimally pruned and allowed to sprawl within the structure. However, the flimsy, cone-shaped cages sold at most garden centers are inadequate for the weight and height of a mature indeterminate vine, often buckling under the load. Building cages from concrete reinforcement wire is more effective, creating a robust support that requires less frequent tying than staking.
Vertical String or Rope systems, such as the Florida Weave or overhead string systems, are highly effective for high-density planting in rows. The Florida Weave uses a pair of sturdy posts, typically T-posts, at the ends of a row, with twine woven between the posts to sandwich and support the stems as they grow taller. Overhead string systems, often used in greenhouses, allow a single leader vine to be trained straight up a string dropped from a high wire, simplifying pruning and harvesting.
Step-by-Step Installation of Support
The support structure must be established early in the season, ideally when the tomato plants are small, around 10 to 12 inches tall. Installing the support early prevents root damage, as waiting until the plant is large risks severing its extensive root system. Stakes or cages should be positioned six to eight inches away from the main stem to avoid contact with the developing roots.
For staking, a six- to eight-foot post should be driven one to two feet into the ground to ensure stability against wind and the plant’s weight. The initial tie-up involves loosely securing the main stem to the support using soft material, such as fabric strips or garden twine. The tie should be fashioned in a figure-eight pattern, with the center cross located between the stake and the stem, preventing the stem from rubbing against the hard support.
For the Florida Weave, a sturdy metal T-post should be hammered into the ground every three to five plants, with strong twine wrapped around the posts at different height intervals. The initial weaving begins when the plants are about a foot tall, providing a foundation that will be built upon as the season progresses. This early installation provides a fixed anchor before the vine’s rapid growth makes handling it difficult.
Seasonal Maintenance and Pruning
Trellising is an ongoing process that requires consistent management to accommodate the plant’s continuous growth. For single-stake and overhead string methods, new growth must be tied to the support every seven to ten days, securing the stem just below a new flower cluster to prevent slippage. Regular tying maintains the plant’s vertical path and ensures that heavy fruit clusters are adequately supported.
Pruning is necessary to manage the plant’s energy and structure by removing “suckers,” which are new shoots that emerge in the axil where a leaf branch meets the main stem. Removing these suckers redirects the plant’s energy into the main stem and existing fruit production, preventing the vine from becoming a dense, tangled mess. Leaving one or two suckers below the first flower cluster can be beneficial to create a second leader stem for increased fruit production.
Toward the end of the growing season, about a month before the expected first frost, gardeners can “top” the plant by cutting off the main terminal growth tip. This late-season pruning halts the production of new flowers and redirects the plant’s remaining resources into ripening the existing fruit. Removing small flowers and tiny fruit that will not mature in time further encourages larger, faster-ripening tomatoes.