There are few things that compare to a garden-grown tomato fresh off the vine. When the time comes to start tomato pruning, things might get a bit fuzzy about how to best do it for your type of tomato plant and the yield you desire. This complete guide will help alleviate some concerns when it comes to the proper methods of pruning, and even the most experienced gardener may find something new to learn about how to prune tomato plants.
Should we Prune Tomato Plants? Why?
Pruning tomato plants is a necessary chore when it comes to growing tomatoes at home for a few reasons, but many wonder, “Should tomato plants be trimmed?”. The answer is “yes,” though only if you’re growing indeterminate tomatoes. Indeterminate tomato plant pruning is beneficial both for the plants and the gardener for such reasons as:
- Increased yield and continued growth throughout the season: by removing excess foliage and suckers, the plant is able to put more energy towards flower and fruit production.
- Lower chance for disease with consistent and sanitary pruning practices: pruning out lower portions of the plant and trimming the leaves periodically can increase airflow and drying between the plant, which reduces the possibility of fungi or pathogens taking hold of the plant.
- Reduced shading of lower portions of the plant: having more even access to light can help with the maturation process of the fruits.
When to Prune Tomato Plants?
The best time to prune tomato plants is around the time the first flowers begin to open up, usually late June to early July in most areas. Then, cut back tomato plants every two weeks after the initial pruning. Stop pruning about two weeks before you suspect the fruits to be ready to harvest, as the additional leaf coverage can help shade the delicate tomatoes during the ripening process.
Pruning tomato seedlings starts relatively early, at about 3 weeks after transplanting into the ground or pot. At this point, your tomato seedling will likely be 4-6 inches (10-15 cm) tall. When suckers begin developing, remove them to strengthen your plant’s main development.
What Parts of Tomato Plants Should be Pruned?
Trimming tomato plants can seem complicated once you first learn the ins and outs. New terms can seem intimidating, but once you know what you’re doing, you won’t soon forget. If you’re growing indeterminate tomatoes, here’s some information on how to trim tomato plants:
- Suckers: these are additional branches that grow between a leaf and the stem, known as the leaf axil. If these are left on your plant, it will drive or “suck” energy away from production on the primary and secondary branches, which will have the most productivity. Removal of these will keep the energy going to the branches that are doing most of the fruit growing. Side stems can also be removed below the first cluster of fruit.
- Lower leaves: These should be removed early to prevent pathogens from the soil from making their way onto your plant. Removing these lower leaves/branches will also help keep the fruit off the ground when it develops.
- Tips: Removing the tips of the branches towards the end of the season will stop further flowering and will send the remaining nutrients and energy toward the fruits that are developing below. This is called “topping,” which is a type of pruning that is usually done later in the growing season.
Methods for Pruning Tomato Plants
It can be confusing when you begin to look into how to prune tomato plants, as there are many different methods that can be employed depending on the type of tomato you have and the harvest you’re looking for. The basics between the methods will be the same: start with clean tools and clean them regularly between cuts and plants.
These methods also assume a healthy, productive plant, so be sure you’re giving them enough water, light, and fertilizer so they will be even more productive after they’ve been pruned. When it comes to trimming tomatoes, you can take a “choose your own adventure” route to find what method you prefer, and once you learn it, you’ll never forget. Here’s a look at some different pruning methods for cutting back tomato plants:
This type of pruning truly lives up to its name: it’s simple because it only involves pinching off suckers when they are young and tender on the plant. Suckers are located between the leaf and stem in an area called the “leaf axil” of the plant. It’s best to do this when pruning young tomato plants because the earlier the suckers are removed your plant will focus its energy on developing the main stems. Additionally, young plants are less susceptible to disease and will heal these wounds quicker. To remove suckers, use clean fingers to grip them firmly at the base and pinch them between your index finger and thumb.
Missouri pruning also involves the pinch off of suckers, though instead of doing so at the branch's base, it’s done at the tip. This method keeps more leaves on your plant, which can help produce more energy for the fruit but is particularly helpful in hot climates where the additional foliage helps shade the rest of the plant. To do this, pinch off or prune the tips of the suckers. This will cause a forking effect of new leaf growth, but be mindful of other sucks that may appear: those will likely need to be removed before your plant becomes nothing but foliage.
Top Pruning (Topping)
This type of pruning is saved for the end of the season’s harvest to help them ripen and develop before the weather gets too cold. Trim the terminal bud above the last flower to allow the nutrients to go to the fruits beneath this point. This is best done about a month before the first frost is expected.
Pruning a tomato plant doesn’t normally conjure up the idea of pruning roots. However, root pruning can be beneficial if you’re looking to mature your plant quicker than normal, and it should be done after the fruits on the plant have developed but before they ripen. To root prune, insert a spade or long knife 3-5 inches (7.5-10 cm) from the base of the plant and cut an arc halfway along the plant about 8 inches (20 cm) deep into the soil.
Pruning Tomato Plants in Pots (Containers)
Growing tomatoes in pots pruning don’t differ much from when pruning tomatoes that are grown in the ground. The difference that matters is whether you’re growing determinate or indeterminate tomatoes.
Indeterminate tomatoes are those that fruit and flower throughout the season, ensuring a crop that can last you up until a month before the first frost. Here are some moments to take into account when it comes time to trim your tomato plant:
- First flowers: the first flowers can be removed to encourage further flowering when your plant has become a bit more robust.
- Removing suckers: remove suckers from your tomato plant once they’ve gotten about 2-4 inches (5-10 cm) long. They shouldn’t get too thick or be diverting too much energy from your plant at this size, but letting them grow longer can keep energy from being used to develop the main stems, which will bear more fruit. This will need to occur more regularly for potted plants than plants in the ground, so stay vigilant!
- Diseased, dead, or broken branches: these can be pruned at any time and should be pruned once they’re noticed. Not only can they encourage further damage to your plant by potentially spreading diseases or pests, but they also will affect your harvest of tomatoes.
Determinate tomatoes don’t need to be pruned, as all of their tomatoes will grow and ripen within a few weeks of each other. Still, you can keep an eye out for a few signs that your tomato plant may need a bit of a trim:
- Diseased, dead, or broken branches: these should be removed as they appear on your plant using sterile tools and cleaned between use and plants.
- Suckers: like indeterminate tomatoes, determinate tomatoes will also grow suckers. These suckers that grow below the first flower cluster should be removed, though that’s the extent of simple pruning this type of tomato needs. You may find that to keep your determinate tomatoes in a pot, you’ll have to trim some foliage to keep it tidy.
Mistakes to Avoid When Pruning Tomatoes
When learning how to trim a tomato plant, it's helpful to keep in mind what not to do too. Improper pruning can lead to stunted growth and fruit production and can cause regrowing issues for the rest of the season.
- Pruning too much: Too much of a good thing is usually a bad thing, and pruning is no different. Excessive pruning can stress your plant and reduce how many flowers (and, therefore, fruit) your tomato plant will yield. Never remove more than ⅓ of the leaves on your plant at a time. This will prevent the sun from scalding the fruits but will also reduce the plant's stress reaction, ensuring you will still have plenty of tomatoes to harvest when the time comes.
- "Topping" early: removing the tips of the top branches will send all of the energy and nutrients to the fruits below, ripening them quicker. This is great for end-season harvests, but doing this too early in the season can end your plant's fruiting and flowering. Avoid topping your tomato until about a month before the first frost is expected.
- Pruning determinate varieties: determinate varieties grow all of their tomatoes at once. Pruning these varieties above the first set of flowers can result in loss of potential harvest, as determinate tomatoes have a set amount of buds that will grow on the plant. Don't prune these plants above the first flower cluster to avoid yield issues.
- Pruning in hot, damp weather or when your plants are wet: Pruning when your tomato plant is wet or in hot, humid weather can make your plant more susceptible to pathogens and other stressors that may affect your harvest or the quality of the fruits. Prune on dry days when it's slightly overcast, if possible, and never prune when your plants are wet.
- Waiting too long to prune: the longer you wait to prune, the thicker and heavier suckers will be on indeterminate varieties. This can weigh down your plant and even break off stems, which can severely damage the number of tomatoes your plant will yield. Aim to remove suckers early to avoid this issue.
How to Trim Tomato Plants to Produce More Fruit?
Indeterminate tomato varieties provide consistent fruits throughout the growing season, and there are ways you can trim your plant to enhance your harvest!
- Remove the first set of flowers, and continue removing flowers until your plant reaches a more mature size of 12-18 inches (30-45 cm) tall.
- Remove all suckers beneath the first set of flowers so they don’t draw energy away from where the plant needs them the most.
- “Topping” at the end of the growing season will give you one last flush of fruits before the danger of frost becomes apparent.
What Should we not Cut Back on Tomato Plants?
Avoid pruning the main and secondary stems on your tomato plant, as these are the thickest portions of your plant that will often produce the most fruit.
It’s best not to trim off too many leaves on your plant at once; remove a maximum of ⅓ of the leaves if necessary; more than this will shock your plant and affect flowering and fruiting.
Do we Need to Stake Tomatoes?
Staking tomato plants is more for the indeterminate varieties since they are pruned frequently, which will encourage more growth. Tomato plants can get fairly tall and, with fruit, heavy. Without staking, the weight of the plant can pull it toward the ground, where it’s more susceptible to pathogens or pests preying upon it. If you’re growing determinate tomatoes, there’s no real need to stake them unless they’re getting very heavy.
Best Ways to Stake Tomato Plants
Staking tomatoes becomes necessary if you’re keeping up with pruning indeterminate varieties and can also be helpful for a mature determinate tomato for some extra support.
- Stake at planting: staking your plant early while the roots are still developing can help with the structure of your plant. Staking too late can damage roots and therefore affect your plant’s yield and health.
- Stake deep enough: be sure you’re staking your tomatoes about 12 inches (30 cm) into the ground. If you’re using containers, be sure your pot is at least 12 inches (30 cm) in depth so you can stake it securely.
- Use support: you might find wire cages or securing your plant to the trellis or stake will be best to support the growth and weight of your plant.
How to Make Tomato Plants Bushy?
Tomato plants can be made to look bushier by pruning the tips of new branches on the main stem. This will cause two stems to branch off in place of one, lending to a fuller appearance.
How to Maintain Tomato Plants?
Maintenance of your tomato plant simply involves pruning, harvesting your fruits, and trimming dead or diseased branches as they appear. Fertilizing regularly throughout the growing season will also help keep your plant vigorous.
Should I Trim Lower Branches on Tomato Plants?
The lower leaves and branches on tomato plants can be trimmed to keep them from touching the ground. This can help prevent the transmission of soil pathogens onto the plant.