Pruning Tomato Plants

By Olivia Barrera – Gleaners Nutrition Education Team

Growing your own tomatoes is one way to savor the flavor of a Michigan summer. Home grown, vine ripened tomatoes are savory, sweet, and come in more varieties than you can find at the store. As long as you have a sunny spot, some soil (in a pot or in the ground), a tomato cage, and a little time, you can grow delicious, nutritious tomatoes at home.

Tomato seedlings can be transplanted outside once the risk for frost has passed, a good rule of thumb is to wait until after Mother’s Day. After your tomatoes are established, they will benefit from regular pruning. This is because tomato plants want to sprawl out and grow bushy. Without the support of a cage, they wouldn’t grow upright at all! Without pruning, they can become unruly, overgrown, and hard to handle. A good time to start pruning tomatoes is once flowers are opening and the plant is established. Pruning your plants throughout the growing season is the best way to contain them and keep them manageable so you can enjoy your plants and harvest them easily. Opening the under-canopy for airflow with pruning will mitigate disease and according to MSU Extension, tomatoes can also grow larger if your plants are kept pruned!

Tomato Tip: remove any branches with leaves that touch the ground at planting and onward!

Tomato plants can be determinate or indeterminate type. Determinate tomatoes will only grow to a certain height and are more compact whereas indeterminate tomatoes are more vinelike and will continue growing for as long as conditions allow. Indeterminate tomato plants require more rigorous pruning than determinate varieties. Indeterminate types include many varieties of heirlooms, beefsteaks, and cherry tomatoes, but these could be determinate as well. Commonly, Roma tomatoes and cherry tomatoes can be found as determinate varieties.

How to Prune Tomatoes: 

Find a small new branch growing between the main stem and a mature, horizontal branch. It will be growing at about a 45 degree angle – this is known as a “sucker” and is the part we want to remove as we prune.  You can pinch the sucker off the plant with your fingers if it’s really small (less than two inches long) or use sanitized gardening shears to remove larger ones. As you can see in the photo below, a sucker starts out as just a few soft leaves (this is a great time to pluck them). MSU Extension suggests not removing suckers that have grown to six inches or more. Dispose of discarded plant parts in a compost pile or throw them away, try not to toss them in the soil near your tomato plants as this can encourage pests and diseases.

Photo: Tomato plant in the Detroit Food Zoo, Olivia Barrera

Disclaimer: Don’t prune too close to the top of your plant unless you’re familiar with growing tomatoes. Cutting off the wrong top growth could result in “topping” the plant which stops the plant from growing altogether. However, topping the plant is a useful strategy at the end of the summer when we want our tomato plants to dedicate all of their energy to ripening the remaining fruit on the plant rather than growing more foliage!

Home grown tomatoes are one of the best parts of summer in Michigan, we hope these tips help you to have a fruitful growing season!

Sources:

We recommend reading Growing Tomatoes in a Home Garden by UMD Extension (link)Growing Tomatoes in a Home Garden | University of Maryland Extension (umd.edu), Prune your Tomatoes for Maximum Size by Ron Goldy, MSU Extension (link)Prune your tomatoes for maximum size – Vegetables (msu.edu), and Pruning Tomatoes and Peppers for Healthier Plants and a Stronger Harvest by Nick Frillman, UIUC (link)Pruning tomatoes and peppers for healthier plants and a stronger harvest | Illinois Extension | UIUC to learn more!