Why and How to Prune Tomatoes

7 Jul

Remove suckers below
the first cluster of flowers.

While staking and pruning is considered by some commercial tomato farmers to be a waste of money – purely because it is so labour intensive – this doesn’t apply to the average home veggie garden. More often than not home gardens have very limited space and so staking tomatoes is recommended to enable more tomato plants to grow.

There are many different ways that you can stake tomatoes though, and you should be aware that the method used will affect whether or not you need to prune tomatoes. For example the inexpensive method of using wooden post strung with natural fibre twine is a great space saver, but plants must be pruned if you are going to make the most of the method.

Pruning if You Use Round Tomato Cages

If you use round tomato cages for support, you will generally need to prune rather radically since they only provide support to shorter stems. Some specialist cages intended for commercial use are huge and generally negate the need to prune, but they are also expensive and not always easy to find. You can also make your own wooden or bamboo “cages” by linking four tall uprights with shorter horizontal length of dowel or thin bamboo. These will also negate or at least minimise the need for pruning. Constant pruning is needed if you use the traditional one-stake method, which in turn reduces the yield.

Which Tomato Varieties Benefit from Pruning?

So which tomato cultivars benefit from pruning, and which don’t?

Generally a good rule of thumb is that indeterminate varieties do need to be pruned. These keep growing and can reach heights of up to five metres or 15 feet – and will continue to produce fruit for three to five months.

Determinate varieties, on the other hand, don’t need to be pruned, although they should be staked. You can remove suckers that form below the first clusters of flowers. Determinate varieties grow to form a bush about a metre or three feet high, and then stop growing, and produce their crop over a period of weeks. Multi-celled American cultivars also don’t need to be pruned; in fact it has been found that pruning leads to reduced yields.

How to Prune Tomatoes

To prune tomatoes, you simply remove lateral stems when the plants are about 300 mm or a foot high and the laterals are about 30 to 50 mm (or one to two inches) long. Bend gently until the stem snaps. Don’t use a knife or pruning shears, and don’t use your nails as this can lead to viral diseases.

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