by Bethany Hayes
Have you ever seen a gardener mention that they topped their tomato plants? Topping tomato plants is a type of pruning that might seem counterproductive, but when done correctly in the right circumstances it can lead to prolific harvests and healthy growth.
Tomato plants come in two varieties: determinate and indeterminate tomatoes. Determinate tomato plants are self-limiting and rarely grow above four feet tall. Indeterminate tomatoes, on the other hand, continue to grow until the first frost of the year. It’s not uncommon for these tomato plants to reach over six feet tall.
Pruning is a vital part of the care of indeterminate plants, but not all pruning is the same. One method you might want to use is topping, and you want to use this correctly to avoid damaging your tomato plants.
So, let’s dive into what it means to top tomato plants and how it benefits your plants.
What is Topping Tomato Plants?
Most people know that pruning indeterminate tomato plants helps your plants stay healthier with fewer diseases and lead to a better harvest. Topping is a form of tomato pruning, but it is different. The biggest difference is that regular pruning only has you remove the suckers or the branches that decrease airflow, but topping is when you cut off the top of your tomato plant.
Yes, really, you cut off the entire tops of your tomato plants.
It’s important to note that topping tomato plants only generally applies to indeterminate tomatoes unless your goal is to ripen the fruits because frost is coming. Otherwise, pruning determinate tomato plants will lead to s a significant reduction in your harvest.
The Benefits of Topping Tomato Plants
Topping tomato plants comes with several benefits, which is why gardeners continue to use this practice. It sends sugar and nutrients to other parts of the plant.
We don’t see it, but tomato plants have a lot going on, and the plant has to decide where to send its energy. In some cycles, the plant sends more energy into foliage growth or growing in height. At other times, the plant sends more sugars and nutrients to flowering and fruits.
With that in mind, here are some of the benefits of topping.
- Easier to Support
If you grow indeterminate, heirloom tomatoes, don’t be surprised if some of your plants reach over six feet tall. The vining varieties excel at growing tall, which can be a problem when it comes to supporting.
This year, a few of my tomatoes grew so tall that they ended up fall over the tops of the cages and breaking. Topping tomato plants keeps them within a certain height and makes it easier for the support system to keep them growing correctly.
- The Plants Are Healthier
Tomato plants grow back healthier after topping. During a traditional growth cycle, the fruits compete with growing stalks for the sugars created by the plant through photosynthesis and nutrients absorbed in the soil.
When we remove the top of the tomato plants, it stops that competition between the fruit and the stalks. All the sugars are sent in the appropriate cycle instead of being divided into different places.
- It Leads to Thicker and Sturdier Plants
If you have a leggy tomato plant, topping the plants helps lead to a bushier, thicker, and sturdier plant, capable of withstanding wind and rain. In addition, topping plants prevents upward growth, so the plants send more energy into producing fuller lateral stems.
- Plants Flower More Prolifically
After topping the plants, you’ll notice that the plant puts more energy into creating more flowers after recovery. More flowers lead to more fruits that you’ll harvest in a few months.
- Topping Helps Plants Ripen Existing Fruits
One of the only times you should top tomato plants is when the first frost of the year is coming, and the plant still has tons of unripened fruits. When you cut off the tops of the plants at this late stage, the plant sends all of its energy into ripening fruits rather than growing new foliage or increasing in height.
Downsides to Topping Tomatoes
Some gardeners never top their tomato plants for several reasons, so you have to decide what works best for you and your garden.
- It’s One More Thing to Do
Let’s be honest; gardening is a lot of work. You’ll spend hours in your garden, and topping tomatoes feels like one more thing that you have to do. Sometimes, it feels daunting to add something else to your to-do list.
- You Have to Keep Doing It
Once you top certain varieties of tomatoes, it becomes a task that you need to continue to do. That can feel overwhelming, especially if you have a large garden.
- It Doesn’t Work for All Tomato Plants
Not all tomato varieties should be topped, and for some, keeping the differences straight can be confusing at times. You never want to top a determinate tomato plant.
- You’re Wasting A Lot
Cutting off tons of a plant feels wasteful. While you can compost the cuttings, after all the time it took to grow those plants, it feels wasteful to cut them.
When is the Best Time for Topping Tomato Plants
Tomato topping is the last necessary pruning your plants need in the growth cycle. The best time for topping is 30 to 45 days before the first frost in the fall. However, some top them 60 days before the final frost; remember that ripening often takes two to three weeks!
It’s hard to predict the timing of your first frost since Mother Nature is never predictable, so use the recommended USDA first frost date based on your USDA zone.
How to Top Tomato Plants
Topping tomato plants is a bit different from regular pruning. It doesn’t require the removal of suckers, and while airflow is essential, you don’t worry about that when topping.
Instead, here is what you need to know.
- Top the Plant When It Grows Over The Support System
One of the best times to top your plants is when they reach the top of their support system. Strong cages are typically five to six feet tall, so at this point, topping tells the plant that it’s time to stop growing taller and send more energy into flowering and fruiting.
Here’s what you need to do.
Take sharp garden scissors or shears, and cut off the top of every vertical stem. This cut needs to be ¼ inch above a side shoot from the main vertical shoot.
- Remove Suckers at the Top
You also want to make sure you cut off any suckers near the top of the plant. Suckers will develop into a new stem. However, make sure you leave the leaves at the top of the plant because the fruits receive energy and sugar from the leaves above them.
- Cut Back the Top Weekly
You’ll need to cut back the tops of the plants weekly because the plant will put on new growth. The plant will send energy into the lateral stems the more often you cut the top.
Typically, it’s healthier when the plant grows back, but you’ll notice that the side branches get longer and too big for your support system. Also, the plant will gradually send energy back to creating new growth instead of the fruits if you don’t keep topping the plants.
When Not to Top or Prune Tomato Plants
Not all tomato plants should be topped or pruned. You already know that pruning determinate plants is generally considered a no-no. The only tomato plants that need to be pruned or topped are ones that need to be staked or caged.
However, you also should never prune plants suffering from blossom-end rot. Rather than making it better, pruning makes blossom end rot worse. This is also true for any plants with cracking fruits.
Topping tomato plants has two primary purposes: preventing excessive growth and forcing fruits to ripen before frost. With that in mind, make sure you time the topping correctly and keep up with the cutting each week to stop the plant from growing back. The health of the plant and harvest size will show why topping is a great idea!