Why and how to Prune Your Tomatoes

If you haven’t pruned your tomatoes before, now is a great time to start! This simple process has many advantages including improved air circulation and better light penetration, both of which can prevent disease. It also yields good-sized fruit and more manageable plants that take up less space and are easier to trellis.

The only tool you will need is clean pruners. You can play it safe by keeping some disinfectant handy to sterilize your pruners between plants, or between garden beds if you’re concerned about spreading disease. If you have a lot of plants to prune, wear gloves to keep your hands from turning dark green by the end.

  1. The first step is to identify the parts of your tomato plant. Find the main stem and look for the places where suckers and leaves branch off. The leaf has leaflets and points straight out or slightly down, whereas the sucker points slightly up and is located above the leaf. Together they make a “K” shape with the main stem (see photo). Suckers can be tiny or large and have their own leaves, suckers, and even fruit clusters!
  2. Photo showing suckers and leaves on a tomato plantNow identify the fruit clusters, which can have buds, yellow flowers, or even small green tomatoes.
  3. Experts advise pruning indeterminate tomatoes to two vigorous stems: the main stem and one sucker. This will give the plant a “Y” shape.
  4. To determine which sucker to leave, locate the lowest fruit cluster and leave the sucker immediately below that. Remove all other suckers from the plant. Small suckers can be snapped by pulling to the side with your fingers, but use your clean pruners for larger suckers, particularly the ones at the bottom of the plant.
  5. With determinate tomatoes (check the seed packet, label, or look up the variety if you’re not sure) remove all suckers below the lowest fruit cluster.
  6. Lastly, remove the lower leaves that touch the ground or are yellowing. This reduces the chance for soil-borne diseases to reach the plant leaves and fruit.  If you have powdered cinnamon at home, apply a little bit on the exposed part of the stem after the cut. Cinnamon is a fungicide and can help prevent diseases from reaching your plant after pruning

Yields will increase and the chance of disease will decrease with regular pruning.

If you’re in St. Lawrence County, contact our Growline for gardening advice at SLCGrowline@gmail.com. Our Master Gardener Volunteers will happily answer your questions.

Erica LaFountain is Community Horticulture Educator and Master Gardener Coordinator for St. Lawrence County. She has a background in organic vegetable farming, gardening, and orcharding and has a homestead in Potsdam, NY.

Meet the Local Foods Team: Erica LaFountain

 

What is your role on the local foods team?

I’m the Community Horticulture Educator, so I help county residents with gardening questions and skill-building through programming. I also coordinate a dedicated group of Master Gardener Volunteers who amplify this work, and I teach classes to the public as well as BOCES Ag Studies Academy students, NorthWind after-school students, and 4H.

How did you come to be in the North Country?

I consider my dad both a local and a back-to-the-lander. He left after college and returned to the North Country with a young family. A generation later I followed that same trajectory. I left the area for college in 2000 and returned with my partner and first child in 2013 after some years pursuing farming, community gardening, and cooperative living in Ithaca and Boston. The land prices here are a real draw and enabled my family to start an orchard and garden and to pasture goats and chickens. Raising my kids in the same special place that formed me has been a real gift. I believe the North Country forges resilient, resourceful, appreciative people.

Read more Meet the Local Foods Team: Erica LaFountain