Everyone loves tomatoes. They are easy to plant, grow fast, and can be used in so many recipes. However, they also have a big problem: they’re high-maintenance plants.
Not only are they heavy feeders, but they’re also highly sensitive to water fluctuations and more prone than others to pests. And don’t forget that quite often they also need support, like cages or stakes.
Another thing to underline is that tomatoes need regular pruning, otherwise you’ll be dealing with overcrowding.
Pruning improves air circulation and helps direct the plant’s energy toward producing healthier fruits. It also promotes sunlight exposure, preventing diseases and unnecessary foliage.
The thing is, pruning may help your plant live longer or give it a premature death, depending on how you do it. That’s why it’s important to do it the correct way.
Pre-Pruning
Before attempting to prune your tomatoes, you should look closely at the plant and identify its parts to make sure you’re only cutting the unnecessary ones.
Tomato plants have one thick main stem with secondary stems coming out of it. These secondary stems are called the suckers, and it’s essential to set them apart for pruning.
The suckers will often come out of the main stems at a 45-degree angle, and they’ll have flower buds and leaves coming out of them. Each sucker can act like the main stem of another plant if you’re planning on propagating.
PRO GARDENER: If you’re looking at a fragile stem with only leaves growing on it, that’s likely not a sucker. Remeber that suckers are more robust and tend to grow between the main stem and a branch at a 45-degree angle, usually with both leaves and flower buds.
How to Prune Tomatoes: Determinate vs. Indeterminate
The way you should prune your tomatoes depends on their type. There are two different strategies that need to be changed based on whether the plant is determinate or indeterminate.
Determinate Tomatoes Pruning
Determinate tomatoes are called that because they have a determined height and lifespan. They only grow to 4–5 feet long, and they die off at the end of the season when the fruits ripen at the same time. They also often have one flower bud at the top with no more potential for growth.
Determinate tomatoes are often better for small spaces because they don’t expand as widely as indeterminate tomatoes. On top of that, they give a consistent amount of fruit that comes out at the same time, allowing for easier season planning.
To prune determinate tomatoes, you should locate the first flower bud on top of the plant. Then, start removing all suckers anywhere below it.
If you find some leaves touching the soil, chop them off too; they’re not doing your plant any good.
It’s better to use sterilized shears for cutting larger suckers, but if you’re looking at a young sucker that’s still fragile, you can snap it off with your fingers. It causes less damage that way.
While pruning, make sure not to cut anything above the flower bud. You may kill off the fruits that are still growing if you do that.
Indeterminate Tomatoes Pruning
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Unlike determinate tomatoes, indeterminate ones keep growing and producing fruits until they’re killed by frost, disease, or any other reason. They need considerable space and stable weather conditions to grow season after season, and they have multiple flower buds that produce fruits.
While you can just let your indeterminate plant sprawl without pruning, it’ll take unnecessary space and possibly spread disease, so it’s always better to prune them.
To prune these types of tomato plants, the first thing to do is to remove all the low growth because it’s not doing the plant any good. Then, locate the main stem and the suckers coming out of it.
Depending on how large you want your plant to be, you can remove all suckers or leave a couple of them to produce fruits along with the main stem.
It’s recommended to cut most of them off and propagate them in a different place. You can still leave around three or four suckers if you want. If you leave more than that, you risk that the plant grows too large.
While choosing which ones to remove, make sure to remove the ones growing low because they won’t get enough sun to produce fruits. You should also remove the ones without flower buds on them because they’ll hardly grow fruit.
PRO GARDENER: If you sense that your indeterminate tomato plant is nearing the end of its life, you should take the top tip off. That way, no more fruits will grow, which will direct the plant’s energy toward the already-existing ones. Otherwise, you may end up with plenty of undeveloped fruits that’ll never fully grow.
Of course, along with pruning, make sure to follow a series of tips to help your tomatoes grow healthy and strong. For example, watch out for hornworms that often target tomato plants. I explained how to identify and get rid of them in this article.
Biggest Mistakes to Avoid
Cutting Too Much
As we’ve seen determinate tomatoes (also called bush varieties) grow to a certain size and stop, for this reason, they do not need excessive pruning.
In fact, pruning them too much may even be more harmful than beneficial, as it can drastically reduce the harvest.
The same thing applies to indeterminate plants. They definitely need pruning but always do it gradually. Removing too many branches in one go can shock your plant and slow down growth.
Using Dirty Tools
Another mistake I see way too often, and that many completely overlook, is using dirty tools.
What many people don’t know is that (just like with humans) pruning with dirty shears can spread diseases from plant to plant.
For this reason, it could be beneficial to disinfect the blades with a solution like rubbing alcohol on your gardening scissors when you go from one plant to another.
Forgetting to Support the Plant
After pruning, the plant can grow faster and taller, and without support, the stems may bend or break.
When you finish pruning always examine the plant. Check if there are any branches that need support and use sticks if necessary.
Pruning When Plants Are Wet
One thing you should never do is to prune plants when the leaves or branches are wet.
Different studies showed that wet plants are more vulnerable to diseases, and pruning while the leaves are damp makes it easier for bacteria or fungi to get in.
Remember that this applies not only to tomatoes but to all plants in general. To avoid all other mistakes, be sure to take a look at the most common mistakes that all inexperienced gardeners make.
