How to Prune Tomato Plants to Get Amazing Harvests

Pruning is one of the biggest factors that separates great tomato success from just moderate success because learning how to grow tomatoes is pretty simple. It’s the things that you do to the plant after planting, like pruning and staking, that will take it to the next level.

In this blog post and video, I will share how to prune tomato plants using the single-stemming method for maximum productivity and health, a simple method for staking tomatoes, and more great tips for growing the best tomatoes!

I Love Growing Tomatoes in My Garden

I’ve been growing tomatoes throughout my gardening career and absolutely love growing amazing heirloom tomato plant varieties every year. In that time, you can bet that I’ve tried almost every method and seen almost every problem.

It’s a privilege to share years of tomato gardening know-how with you by answering your questions like why do tomatoes split, how to Florida weave tomatoes, why tomato plants drop flowers, how to grow tomatoes in containers, how to get rid of tomato hornworms, and this post on how to prune tomatoes properly. I hope you will glean from my knowledge and learn from my mistakes!

Which Tomatoes Need to Be Pruned

If you prune a determinate tomato plant, you will be decreasing your yields. If you fail to prune an indeterminate tomato plant, you will end up with a huge, tangled, less healthy mess.

That is why it's important to know which type of tomato plant you have planted in your garden before pruning. The type of plant will dictate which method of pruning and staking you should use!

If you have planted determinate or semi-determinate tomato plants, you do not want to prune them to a single main growth stem! Instead, provide them with about 3 feet of support using a tomato cage or something similar.

The Benefits of Pruning Indeterminate Tomato Plants

I've seen firsthand how good pruning can make tomato plants healthier and more fruitful (just like pruning grape vines will). Proper pruning resolves about 90% of the tomato problems that people write in to MIgardener with!

In this blog post, I’m going to teach you the single stemming method, which I’ve had great success with. But regardless of which method you use, everyone should be pruning at least the lower foliage on indeterminates!

Removing the lower leaves (and other foliage) on tomato plants does a few great things:

• Increases Air Flow - Removing lower leaves increases air flow and gets rid of leaves touching the soil, which are a catalyst for diseases like tomato blight and powdery mildew.

• Gets Rid of Stressed Leaves - The lowest leaves are often stressed and struggling because they just can’t access enough sunlight, plus they get the most splash from rain and watering. Pruning allows you to get rid of any stressed or damaged parts before they cause serious issues.

• Exposes Fruit to Sunlight - If you have a lot of dense foliage on a tomato plant, you will notice that sunlight has a hard time penetrating, and the fruit will stay green for a long time. Thinning the foliage will increase sun exposure and ripening fruit. Pro-Tip: Your tomatoes will actually taste better if you prune! Tomatoes generate sugars from the sun. By having tomatoes that can touch the sun, instead of being blocked by bushy foliage, you will get sweeter, more flavorful tomatoes!

• Allows You to See - I can’t tell you how many times I have accidentally harvested a green tomato or broken the wrong stem because excessive foliage blocked my view. Pruning off the lower foliage allows you to better see what you are doing, making it much easier to maintain the plant. Plus, when you are working up close with your plants you will notice problems like blossom end rot sooner.

• Pest Reduction - Earwigs, slugs, picnic beetles, and other pests love the dark, damp environment created by dense, unmanaged tomato foliage. Removing the lower leaves gets rid of ideal pest conditions. Pro-Tip: If you still have a problem with pests after proper pruning, read these blog posts to learn more about preventative pest control and using organic pesticides like diatomaceous earth.

When to Start Pruning Your Tomato Plants

You can start pruning indeterminate tomato plants when they reach about 1 foot tall, and you can continue to prune as needed all season long.

Don’t worry if you have a large, unruly plant that you’ve never pruned. It will still benefit from pruning. Now is the time to do a tomato plant intervention! 

How to Prune Tomato Plants (Indeterminates)

My favorite tomato pruning method is single stemming. As the name suggests, you keep the plant growth to a single main stem by removing the lateral side growth.

The lateral side growth, also called suckers, are secondary stems that are essentially each their own plant. Suckers restrict airflow and divide up the plant’s energy.

Follow these steps using a clean pair of hand pruners or micro-tip snips to cut the foliage off or pinch it off with your fingers. Start at soil level and work from the bottom up!

Step-by-Step Pruning Instructions

1. Remove Any Growth - Remove all growth at the soil level that is starting to form, except the main growing stem.

2. Remove Lower Leaves - Prune off the lower branches about 10 to 12 inches up the main stem or to the first flowers. On young tomato plants, you may not be able to prune up to 12 inches at the first pruning, but you can work up to this height as the plant grows. Pro-Tip: Some gardeners will continually prune throughout the entire season, without a stopping point. Others will only prune off the first set of leaves. I have found ideal pruning to be somewhere in between those. That is why I recommend pruning everything off the stem 10 to 12 inches up from the soil or to the first set of flowers.
   

3. Identify Suckers - To identify what to prune off and what to keep, follow the main growing stem straight up the plant and remove all the growth in the armpits of the tomato. (The armpit is the area between the main stem and where a leaf or branch grows.) Suckers usually grow outwards at a 45° angle from the armpit of the tomato.

4. Remove Suckers - Grasp the suckers where they connect to the main stem and pinch them off with your fingers or cut them off. Pro-Tip: The suckers you prune off can be used to produce new plants! When pruning, place the suckers directly into a vase of water. Then, remove the bottom couple of leaves and plant the suckers in soil like you would a tomato seedling. It should take 5 to 7 days for them to root, and you will have another tomato plant!

5. Remove Damaged Parts - Prune off any leaves that look unhealthy, yellow, or brown. Pro-Tip: Leaf curl is not necessarily a sign of unhealthy foliage. Read this post on tomato plant leaves curling to learn more!

6. Remove Forks - If the main stem forks and forms a Y, prune off one branch of the Y to keep only one main growing stem. I would prioritize the fork that has the most flowers.

7. Support - After you prune, it's time to choose a support system for your tomatoes based on the variety's growth habit. DIY tomato cages, Florida weaving tomatoes, and other trellises work well. Or, learn how to stake tomatoes as an inexpensive way to provide a firm foundation with plenty of height to support even indeterminates.

I hope you become a tomato defoliator. Tell your friends and encourage other gardeners to become tomato defoliators, too! They’ll thank you later when they have the best tomato harvest ever.