Last Updated: July 14, 2023
To prune or not to prune? That is the question. Veteran tomato growers always have strong opinions on pruning, but what are the facts? Should you prune tomato plants?
In this article, I’ll discuss the benefits and drawbacks of pruning tomatoes so that you can decide for yourself. I’ll also discuss proper pruning technique so that you can trim your plants like a pro. Let’s get started!
The 2 Types Of Tomato Plants
When deciding whether or not to prune, your first step should be to find out the type of tomato plants you have. There are 2 main types of tomatoes:
Indeterminate tomatoes grow continuously, all season long. They commonly trained up a stake or trellis, easily reaching 10′ in length in a single season. These require more pruning than the other tomato type.
Determinate tomatoes have a set height, typically between 3-5′ tall. They grow to maturity and produce all of their fruits in a single harvest. These plants require much less pruning, but can still be trimmed to improve airflow.
Once you know if your tomatoes are indeterminate or determinate, you’ll have a much better idea of whether or not to prune them. Next, let’s discuss which parts of a tomato plant can be pruned, and why.
Which Parts Of A Tomato Plant To Prune
Pruning tomatoes is done on an ongoing basis, meaning that there is no one time that is best to prune. Generally, I trim my tomato plants every 1-2 weeks throughout the season to keep them healthy and tidy.
With all that said, which parts of the tomato plant should be pruned? There is not a single method that you must follow. However, these are some general guidelines I recommend for pruning tomato plants:
- Prune suckers. Suckers are essentially side shoots that are capable of forming leaves, fruits, and even more suckers! They are commonly pruned off of indeterminate tomatoes, but not determinate types. There are exceptions to this, for example if you are growing indeterminate cherry tomatoes or have ample space for bushy growth, you wouldn’t prune as many suckers. In general, I will typically leave 2-3 main stems on the plants, removing any additional suckers. Tip: Clone your suckers to make new plants!
- Prune diseased foliage. If your plants show signs of disease, these leaves/fruits should be removed. Disease has a way of spreading, even from one plant to another. Remove and discard the affected leaves whenever you see them.
- Prune low branches near the soil line. Bottom pruning is always a good idea to help avoid disease. To do this, remove any leaves near the soil, about 12-18″ up the plants. This helps prevent soil being splashed onto foliage during heavy rain or watering. Make sure your plants have enough foliage left after bottom pruning.
- Prune excessively dense foliage. Tomato plants need good airflow. Too much foliage can cause high humidity and moisture among the plant, increasing risk of disease. If your plants seem overly dense or crowded, remove a few leaf branches. The goal is to open up the plant a bit and allow for better air circulation. Careful not to over-prune.
- Prune growing tips (late-season only). Later in the season as fall approaches, you can top your tomato plants. This involves cutting off the tip of each plant, stopping upward growth. This will redirect energy down, potentially helping to ripen any remaining fruits faster.
This may seem like a lot, but all pruning techniques are meant to serve a beneficial purpose. The goal is to either improve the health of the plants, or to train them to be tidier and less sprawling.
With these pruning techniques in mind, let’s talk about a few exceptions where you may want to prune differently.
Exceptions To The Rule
While the above pruning methods have helped my grow healthier, more productive tomatoes, there are a few exceptions.
- Trellising side-by-side. Many gardeners will grow their tomatoes in a line, trellising each up a string or tall fencing. This is a great way to save soil space in the garden. This technique must be done with indeterminate types, and requires more heavy pruning, especially of sucker shoots. This pruning keeps the plants tall and slender so that they don’t become overly crowded.
- Cherry tomatoes. While you can prune cherry tomatoes, I don’t recommend pruning as heavily as larger types. The additional suckers and branches can easily produce more cherry-sized fruits. On the flip side, big beefsteak tomatoes will have more difficulty producing full-sized fruits on sucker branches, hence why we remove most.
- Determinate types. I’ve already said it, but I’ll say it again: determinate tomatoes require minimal pruning. My recommendation is to bottom prune, and remove any overly-crowded leaves, and nothing else. No need to remove suckers or try to trellis determinate varieties. Simply let them bush-out, provide support with a cage, and wait for harvest day!
While pruning has its place in my garden, you can always modify it to your needs. If your goal is to grow the biggest, widest tomato plant, then pruning the way I do won’t make much sense!
What happens if you don’t prune tomatoes at all?
All this talk about pruning techniques sounds like hard work (it’s not that bad…). So what happens if you simply don’t prune tomato plants?
Unpruned tomatoes tend to sprawl and produce an abundance of foliage. This dense, bushy structure can lead to smaller yields, more disease, and more difficulty harvesting.
In addition, big messy tomato plants can make it hard to locate and remove hornworms and other pests. If you do want to skip the pruning, I’d recommend growing a disease resistant tomato type.
There are some benefits to not pruning at all. For example, the extra leaves can help shade out weeds and provide protection to fruits from direct sun exposure. It also means less work in the garden.
So, if you’ve got the “I’ll take what I can get” mentality, then by all means don’t prune at all!
Pros of Pruning:
- Helps reduce disease
- Increases airflow around plants
- Keeps plants looking tidy and healthy
- Can be used to save garden space (training plants vertically)
Cons of Pruning:
- Requires more frequent work
- Can spread disease if shears are not cleaned between trimmings
There are endless ways to grow tomatoes: vertically, in cages, even upside down! So remember that pruning is optional and to always feel free to do things your own way.