By Julie Christensen
More has probably been written on how to prune tomatoes than almost any other vegetable gardening task. Unfortunately, advice on pruning tomatoes is usually vague, conflicting or downright confusing. The truth is, tomatoes don’t absolutely have to be pruned. Some gardeners let them ramble on the ground and never prune them a bit.
However, pruning tomatoes is a good idea if you want healthy, productive vines. Pruning is a lot simpler than you might expect, especially if you do a bit every week so the plants don’t become overgrown. Here, we’ve included everything you need to know to become a tomato pruning expert.
The Whys of Pruning Tomatoes
Determinate tomatoes don’t need pruning – ever. These bush-like plants are bred to stop growing at a certain height and stop producing fruit at a certain point. If you prune them, you’ll limit their growth even more.
Indeterminate tomatoes are another story, entirely. These subtropical plants form sprawling vines, which if left to their own devices, become a tangled, unproductive mess. Sure, their foliage is pretty, but you’re not growing tomatoes for their leaves. You want healthy, vigorous tomatoes. Tomatoes need access to sunlight to ripen and sweeten properly. If the vines are allowed free rein, you’ll have fewer fruits and the fruits won’t look or taste as good.
How to Prune Tomatoes
When you first start pruning tomatoes, keep three rules in mind: first, never, ever prune above the top blossoms. If you do this, the plant will stop growing upward. The plant becomes bushier and less productive. Next, prune out suckers when they’re small. If you wait until they’re bigger, you risk injuring the plant when you take them off. You’ve also allowed them to divert energy from developing fruits. What are suckers? They are smaller offshoot branches that grow between the main stem and the branch. Learn more about them here. Here’s a YouTube video that demonstrates, and another shorter one.
Finally, examine the whole plant before you start removing suckers. Are there new suckers growing at the base of the plant? Take them off. What is the plant’s overall health and growth like? Go easy during hot weather or if the plant seems stressed. Still confused? Below you’ll find a step-by-step guide to pruning tomatoes.
- Prune tomatoes early in the morning whenever possible. The stems are crisp and snap off easily. During the heat of the day, they become limp and are more likely to tear.
- Look at the plant. Your goal is to train it so it has one central trunk with several strong, healthy branches. Once you’ve located the trunk and the main side branches, you might notice smaller branches growing in the crevice where the trunk and main side branches connect. These small ancillary branches will try to produce new tomato plants. You don’t want this because it makes the plant large and unmanageable and it actually reduces yields.
- Once you’ve located an ancillary branch, pinch it between your thumb and forefinger to remove it. Try to make a clean break and avoid ripping the plant.
- Drop the ancillary branch under the plant to decompose or discard it.
- Remember, don’t prune any stems that grow above flowers. These are new growth that will form more blossoms. Focus on removing the stems that form along the main branch instead.
- If a second trunk emerges from the ground, remove it. If you have lots of room, you can leave it and allow it to become a second tomato plant, but in most cases, it’s best to take it out.
Whens to Prune Tomatoes
So, now that you understand the principles of pruning tomatoes, you might be wondering how often you need to prune them. In general, once every week or so is usually plenty unless your tomatoes are extremely vigorous. Depending on the size of your garden, spending 15 minutes or so once a week is enough.
Don’t worry if you miss a week or two. Tomato plants will still grow and produce tomatoes even if they’re not suckered, but keeping them pruned increases your harvest and makes them easier to manage.
For more information, visit the following sites:
How to String and Sucker Tomatoes from Front Porch Farm
Pruning Tomatoes from Fine Gardening
Julie Christensen learned about gardening on her grandfather’s farm and mother’s vegetable garden in southern Idaho. Today, she lives and gardens on the high plains of Colorado. When she’s not digging in the dirt, Julie writes about food, education, parenting and gardening.