To stake and prune … those are the questions. Every gardener has his or her own method for pruning their tomato plants. Gardeners also have an opinion on whether or not tomato plants need staking. Here are some of the advantages.
Staking tomatoes helps manage disease problems by increasing air circulation in the leaf canopy and reducing contact with the soil. A structured training system also can make tomatoes easier to harvest. Pruning can help boost yields by exposing more of the leaf canopy to full sun and reducing competition between suckers and the developing fruit.
Several different tomato training systems exist; the type of support to be used depends on tomato growth habit. Tomatoes can be divided into two types, determinate and indeterminate. The determinate varieties have short to medium vine lengths. Plants are heavily branched, and growth stops when they start flowering. Every branch tends to end up with a flower cluster. Determinate varieties are not heavily pruned as most of the fruit is produced on the branches. Indeterminate varieties continue to grow and produce leaves as well as flowers throughout the entire growing season. Pruning methods will depend on the type of support system used.
The three most common training systems for tomatoes are stake and weave, trellis, and cage. All three of these techniques can be used with indeterminate tomato varieties, but only cages and stake-and-weave are used with determinate varieties.
When gardeners prune tomatoes, they remove small side shoots from the main stem. This reduces competition between vegetative growth and the fruit. Pruned plants produce larger and an earlier fruit as most of the plant energy is channeled into the fruit. Prune shoots when they are four inches long.
Staking plants requires metal, such as rebar or t-posts, or wooden stakes. Determinate varieties require 3 to 4 feet stakes and indeterminate varieties require stakes from 5 to 6 feet long. Set a stake between every other plant. Lines of twine are strung between stakes on either side of the plants to provide support.
Caging is a support system that requires less work than staking or trellising but provides similar benefits in protecting plants from contact with the soil. Caged plants may not produce ripe tomatoes as early as staked or trellised plants, but the fruits they produce are less likely to suffer from cracking or sunburn. Be sure to prune the lowest branches to reduce disease.
Gardeners need to decide on the type of support before setting plants in the garden. Plants grown on a trellis system can be planted closer together than those grown in cages or staked. Check your plants regularly to continue training them to the support system and prune as needed.
David Hillock is a consumer horticulturist with OSU cooperative extension.