THE demand for and availability of improved tomato varieties have encouraged farmers and agricultural researchers to investigate the technique of pruning and different staking methods to enhance crop production.

Unlike other plants, tomato for the first month directs all the sugar it produces towards the production of new leaves. During this stage, tomato plants grow very rapidly, doubling in size every 12 to 15 days. Eventually, the plant generates more sugar than the growing tip can use, which signals the plant to make new branches and to flower. This usually happens after 10 to 13 leaves have expanded, at which time the plant is 30cm to 45cm tall.

In the next few weeks, the entire character of the tomato plant changes, if unsupported, the increasing weight of filling fruit and multiple side branches forces the plant to lie on the ground. A vigorous indeterminate tomato plant can easily cover a 1 x 1 m area with as many stems, each 1 to 1.5m long. This creates a haven for disease and pest infestation, poor management of fruit production and low productivity.

A prostrate plant gets around to fruit production two or three weeks later than a pruned and staked plant. Most of the fruits are produced on the small side and tend to come in one big, late harvest.

A properly pruned and supported single-stem tomato plant presents all of its leaves to the sun. Most of the sugar produced is directed to the developing fruit since the only competition is a single growing tip. The result is large fruits that are steadily produced. If more stems are allowed to develop, some of the sugar production is diverted from fruit to multiple growing tips. Fruit production, although, slow never stops. The result is a nearly continuous supply of fruits throughout the season. In general, more steams means more but smaller fruits, which are produced increasingly later in the season.

Pruning also affects plant health. The leaves of a pruned and supported plant dry off faster, so bacterial and fungal pathogens have less opportunity to spread. Soil is less liable to splash up onto stakes plants. The bottom line: Upright plants have fewer problems with leaf spots and fruit rots because their leaves stay drier and free from pathogen-laden soil.
As the tomato plant grows, side shoots, or suckers, form in the crotches, or axils, between the leaves and the main stem. If left alone, these suckers will grow just like the main stem, producing flowers and fruit. Suckers appear sequentially, from the bottom of the plant up.

The farther up on the plant a sucker develops, the weaker it is, because the sugar concentration gets lower as you move up the plant. On the other hand, side stems arising from below the first flower cluster, although stronger; compromise the strength of the main stem. For a multi-stemmed plant, your aim is to have all stems roughly the same size, although the main stem should always be stronger because it has to feed the entire plant for the next five to six months.

The way you choose to train and prune your tomato plants will affect how you space your plants, as well as the best method of support. There are two ways to deal with a sucker that is not destined to become a stem. The simplest is to pinch it off entirely; not surprisingly this is called simple pruning.

This should be done when the sucker is still small and succulent. Grab the base of it, between your index finger and thumb, and bend it back and forth. The sucker should snap off, producing a small wound, which will heal quickly. Avoid cutting the sucker with a knife or scissors, because the resulting stump can become easily infected. Once a sucker becomes too tough and leathery to snap off, however, you’ll have to use a blade.