“You Say Tomato, I Say Tomahto…Let’s (not) Call The Whole Thing Off”

— Written By and last updated by

You just can’t stay mad at someone after you bite into a juicy, still-warm-from-vine, sun ripened tomato from your own garden. So in the interest of diplomacy, let’s all grow the most and the best-tasting tomatoes we can. One way to be success in this endeavor is pruning tomatoes. Before you start, recognize what type of tomato you are growing. There are two types, indeterminate and determinate.

Indeterminate tomatoes are those that have a leaf bud as the apical meristem. What this means is the plant will continue to grow taller (or longer) as you water and fertilize it. You may have seen these plants grow out to almost the 10 feet. Determinate tomatoes are shorter than indeterminate ones because their apical meristem is a flowering bud. Determinate (bush) tomatoes generally remain 5 feet tall and under. Indeterminate tomatoes trellis well, up a fire escape for example. Determinate tomatoes stay shorter and work well in the field or in containers. A few of the more common determinate tomatoes are Celebrity, Better Bush, Roma, Viva Italia and San Marzano. A few of the common indeterminate tomatoes are Early Girl, Better Boy, German Johnson and Big Beef. However, there are thousands of tomato varieties to choose from. Heirloom, hybrid, grafted, and so forth!

As with many herbaceous plants, the fruit and leave are susceptible to pests and disease when they’re laying on the ground. Pruning and using plant support fencing can help create healthier, more productive tomato plants. Pruning keeps plants compact, manageable and prevents sprawl. It maximizes production and minimizes disease problems by opening up the interior growing area, improving air circulation and allowing in the sunlight.

How is it done? There are several ways to prune tomato plants, depending on the type of tomato and the support you use. Typically, pruning is most helpful for indeterminate (vining) tomato varieties. Most tomato pruning involves removing suckers —the shoots that form where side branches meet stems, usually growing at a 45-degree angle. Remove suckers when they’re small by pinching them off at the base or snipping them with pruners. If you wait until the suckers are the diameter of a pencil or larger, you run the risk of tearing into the outer layer of tissue (the cambium layer) leaving an open wound for pests to enter your tomato shrub.

To get the most fruit harvest, take off the suckers that grow BELOW the first cluster of flowers to keep the main stem strong, and eliminate the chance of fruit on lower branches pulling down and rotting on the ground. Leave the top branches on the plant. They will eventually produce flowers and fruit. You want to keep in mind your plants need good airflow to keep down fungal disease, and enough access to sunshine inside for the leaves to do their job – photosynthesis. Prune off any yellowing, dying or diseased leaves, they can’t do their job anymore and are a vector for pests and disease. Be aware of summer sun intensity, which can cause sunscald on fruits (fruit with tough, thickened skin and discolored areas).

In addition to pruning, apply a “sidedress” of fertilizer at first and second bloom. If you use calcium nitrate (CaNO3), you’ll prevent some blossom end rot. Don’t over water, but don’t under water. Don’t water heavily when tomatoes are turning color. Too much, too fast will encourage cracking. Consider drip irrigation and a timer attached to your hose faucet for consistent application of water,

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The use of brand names and any mention of commercial products does not imply endorsement by N.C. Cooperative Extension nor discrimination against similar products not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label.

Minda Daughtry is Horticulture Agent for North Carolina Cooperative Extension in Lee County.