Left on their own, tomatoes will grow into shrubby, multi-stemmed plants that topple under the weight of their fruit. Fruit and foliage are more prone to attack by pests and disease when they’re sprawled on the ground. Pruning and using plant supports can help create healthier, more productive tomato plants.
Advantages to pruning:
- Keep plants compact and prevent sprawl.
- Make it easy to support plants using Tomato Ladders and other supports.
- Maximize production.
- Minimize disease problems by improving air circulation.
Tradeoffs when pruning:
- It removes leaves that would otherwise feed the plant.
- Removing foliage can expose fruit to sunscald.
How to Prune
There are several ways to prune tomato plants, depending on the type of tomato and the support you use. As a rule, pruning is most helpful for indeterminate tomato varieties — large plants that continue to grow taller and produce fruit until killed by frost. Determinate, or bush tomatoes, tend to be smaller and more manageable.
Most tomato pruning involves removing suckers — the shoots that form in the axils where side branches meet the stem. Remove suckers when they’re small by pinching them off or snipping them with pruners.
If your goal is to maximize the harvest, prune suckers sparingly. A good compromise is to remove all suckers that grow below the first flower cluster. This helps keep the main supporting stem strong, but it doesn’t remove upper suckers that will eventually produce flowers and fruit.
Prune sparingly, too, if you live in a place with intense summer sun, which can cause sunscald on fruits (fruit with tough, thickened skin and discolored areas).
In regions with short growing seasons, some gardeners start pruning off suckers in late summer to encourage the plant to direct its energy to existing fruit.
If space in your garden is at a premium, or if you’re supporting plants with Tomato Ladders, stakes or other tall, narrow supports, it’s best to prune your tomatoes to one or two main stems. To do this, pinch out all suckers. Otherwise, suckers will grow into additional stems and create a wide, bushy plant. The remaining main stems will grow strong and sturdy and will be easier to secure to the supports’ uprights with plant ties.