Issues that concern the tomato grower

Most of us have our tomato plants in the ground and are anxiously awaiting that very first tomato sandwich. There are many issues which concern us as tomato growers. The Lord knows there are plenty of problems which plague these most favored of garden fruits. One of these is pruning – whether or not to remove or retain suckers. Read on.

What is a tomato sucker? Suckers are side shoots that appear in the axils, or crotches, between the leaves and the main stem. If allowed to remain, they will grow just like the main stem, complete with flowers, fruit, and more suckers.

Why are tomato suckers pruned? This is done because the suckers compete with the main stem and its fruit for nutrients. While it is true that more fruit will result from leaving the suckers to grow, the resulting fruit will be smaller and the plant will become more cumbersome and thus harder to control. Pruning, therefore, is akin to thinning a shrub.

Pruning also affects the health of the tomato plant. The leaves of a pruned plant dry out faster, being exposed to the sun, so bacteria and fungi have less opportunity to spread and cause diseases. A more compact and well-trained plant, directed upward rather than outward, will tend to have fewer problems with leaf spots and fruit rots because their leaves stay drier and free of soil.

On the other hand, not pruning suckers will cause the tomato plant to develop more cover (shade) for ripening fruit, which can minimize sunburn and scalding. This can be a distinct advantage for varieties that naturally form less cover.

Is pruning necessary? Pruning suckers is not a requirement and many gardeners do not even bother with it at all. However, if you are one of those who do, you will appreciate knowing that whether to do so or not depends on the type of tomato you are growing.

Tomatoes are generally classified as either determinate or indeterminate. Determinate tomato plants have a genetically predetermined number of stems, leaves, and flowers (and thus fruit). Their growth follows a pattern of vigorous vegetative growth with a subsequent flush of flowering and fruit production, after which there is a period of final leaf expansion and an end to further vegetative growth. Commercial growers like this type of tomato because most of the fruit can be harvested at once. Examples of popular determinate varieties are Amelia, Roma, the BHNs, Better Bush, Celebrity, Talladega, Top Gun, Tasti-Lee, among others.

Determinate tomatoes need no pruning other than the removal of all suckers below the first set of flowers. Additional pruning will not affect fruit size or plant vigor. If pruning is done anywhere above the first flower cluster, the tomato harvest will be reduced.

Indeterminate tomato plants, in contrast, continue to grow and produce leaves, stems, and fruit as long as growing conditions are favorable. Indeterminates can have one to many stems, depending on how they are pruned. The fewer the number of stems, the fewer but larger the fruits will be. Popular indeterminate varieties include Beefmaster, Better Boy, Big Beef, Big Boy, Park’s Whopper, and others.

Since indeterminate tomato plants can get extremely large and will keep producing tomatoes all season, they can handle some pruning. If you leave all the suckers to grow, your plants may become heavy and out of control if not well supported. On the other hand, removing all the suckers will result in a more compact plant, but it will also lessen your tomato yield.

As long as you have a strong main stem, it’s fine to leave a few suckers on the plant. The general recommendation is to leave 2 or 3 suckers to improve yield, but not to let every sucker grow.

Tomato pruning is more trial and error than precision, so look at it as an experiment. When you first start pruning, do less rather than more. If you grow the same varieties year after year, you’ll get a feel for how they respond to pruning.

Tim Lewis is a Georgia Green Industry Association Certified Plant Professional, gardening writer, former Perry High School horticulture instructor, and former horticulturalist at Henderson Village and Houston Springs. He and his wife, Susan, own and operate Lewis Farms Nursery located on Hwy 26 two miles east of Elko, where he was born and raised. He can be reached at (478)954-1507, timlewis1@windstream.net, and at LewisFarmsNursery.com.

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