Have you ever selected and planted a beautiful young tomato plant only to find it growing erratically and under-producing?
Or perhaps your plant buckles over under the weight of too much fruit?
What you might be missing in your tomato care regimen is a really good pruning method.
That’s right, when and how you prune your tomato plant has a great deal to do with what kind of plant you will grow and the harvest you will reap.
Why it is important to prune tomato plants
If you don’t trim tomatoes they will become a heavy shrubby, multi-stemmed plant that will fall over once they have fruited.
Additionally, when fruit and foliage are on the ground they are more prone to disease and insect attack. Pruning allows for adequate air circulation and creates a healthy, compact and productive plant.
Tomato suckers, also known as side shoots, appear in the crotch between the stem and a branch.
A close up view of a tomato sucker emerging between the main stem and branches.
If not pruned, they actually morph into another main stem with branches, flowers, and more suckers.
Although you may get more fruit if you let the sucker grow – the fruit will be considerably smaller.
It is important to trim away these suckers early on as they compete with the main stem for nutrients.
What about determinate vs. indeterminate tomato plants?
There is no need to prune determinate tomato plants as they already have a compact habit. They generally reach a certain height and stop growing, setting fruit once all of their branches have finished growing, all at one time.
Indeterminate tomato plants, on the other hand, just keep growing and growing and produce fruit until the first frost.
How to prune tomato suckers
There are various ways to prune suckers.
Some gardeners prefer to prune out everything that is below the first flower cluster for strong stem growth. Others often leave a couple of suckers on the lower portion because these can be easily supported by staking.
To keep it from becoming too top-heavy, they prune the suckers from the top half.
Pruning tends to be somewhat experimental – do what works best for you. Just remember that you will have to prune suckers all summer long so check your plants frequently.
5 Steps to Prune Tomato Suckers
Prune suckers when they are small
To remove a sucker, grab the tip between your thumb and forefinger and bend it back and forth until it snaps.
Pinching off a young tomato sucker.
Do this when suckers are young because the small wound will heal quickly.
Stems that are thicker in diameter than a pencil should be removed with clean and sharp snippers.
To maximize harvest
If your goal is to maximize your harvest, prune suckers only sparingly. As mentioned above prune only below the first flower cluster.
If you live in a hot location
If your summer sun is intense, it is best to prune only what you need to in order to avoid sunscald on fruit. Allowing more branches to form shades the rest of the plant.
Ladders and stakes
When garden space is a premium or you are training tomatoes to a ladder or stake it is best to prune your tomato plants to one or two main stems only.
Pinch off all suckers to create a compact and sturdy plant that can easily be supported.
Tomato cages or towers
If you are training your plants to a cage or tower it is best to pinch off suckers on the lower end of the plant but allow suckers higher up to grow.
Additional tomato pruning tips
Remove the lower leaves when planting your tomato plant so that you can bury the plant deep within the soil.
When planting, remove any flowers. You want energy to go to leafy growth, not flowers at this time.
Remove the flowers until your plant reaches about 12-18 inches tall. This ensures a strong and healthy root system.
Late in the season, you may still have quite a few tomatoes on your plant. To speed up ripening, remove the growing tip of each main stem four weeks before you expect frost.
This process, called “topping” causes the plant to stop flowering and setting new fruit. This allows all the energy to go to the remaining fruit. This will allow the fruit to ripen quickly and even if you pick green tomatoes they should ripen indoors.
There are a number of more ways to speed up the ripening of your tomatoes. Here’s our article sharing the top ten.
Clone your tomato plant from cuttings
If you’d like to grow a brand new tomato plant from the suckers you prune off, then you can do that.
Your new tomato plant will have exactly the same characteristics of the plant you prune it from, so it’s a brilliant way to clone a plant you particularly love. Share it with friends or family, or just increase your tomato stock.
Fertilizing your tomatoes
While pruning is vitally important to the success of your tomato harvests, feeding them the nutrients they need is also a part of the equation.
I’ve been growing tomatoes for 30+ years and after a lot of trial and error, this is my go-to tomato fertilizing process.