How to Prune Hydroponic Tomatoes


Tomato pruning typically involves the removal of side growths called suckers that sprout from the joint between branch and stem. Too many of these cause the plant to sprawl. By careful pruning you can correct this tendency, creating a custom-plant architecture conforming perfectly to your greenhouse, closet or other specialized hydroponic environment. Thoughtful pruning creates space between the branches, allowing better airflow and easier manual pollination. Most importantly, it helps concentrate the nutrients you've painstakingly added to the system's reservoir into fewer but plumper tomatoes.


Step 1

Verify your tomato variety is an indeterminate. Indeterminates include such varieties as Supersonic, Big Boy, Big Beef and other beefsteaks. They grow as large as you'll let them, producing many branches and suckers. They will benefit from a thorough pruning.

Step 2

Choose one to three suckers sprouting from the base of the plant to preserve. These, along with the original main stem, will produce all of your tomatoes.

Step 3

Remove all other suckers. Allow each to grow to about 3 or 4 inches long before gently breaking them off at the base by hand.


Step 1

Verify your tomato variety is a semi-determinate. Semi-determinates include Celebrity and Mountain Pride. Not as compact as determinates nor yet as sprawling as indeterminates, they will produce many suckers but only grow to between 3 and 5 feet. They prefer a more restrained pruning.

Step 2

Wait for the plant to reach a height of 8 to 10 inches and begin producing flower clusters, also known as fruit trusses.

Step 3

Find the first (lowest) fruit truss and identify one or two suckers immediately below it. Remove all suckers below that.

Step 4

Repeat the previous steps about seven to 10 days later, if necessary.

Step 5

Allow all other suckers to flourish.

Support and Maintenance

Step 1

Support remaining stems from above with plastic twine or a plant yo-yo suspended from an overhead wire, clothesline or closet hanger bar. This will encourage vertical growth.

Step 2

Remove leaves as they begin to yellow and wither near the bottom of the plant. This further encourages air flow and helps prevents infection.

Step 3

To prevent sunburned fruit in a greenhouse situation, allow five to seve leaves to grow above the last (highest) flower cluster you want to produce fruit. After this, remove all new fruit trusses from above these shade-providing leaves.

Tips and Warnings

  • Don't prune suckers from determinate varieties. You'll end up with a drastically reduced yield. Don't rob yourself of an early yield by pruning the first flower buds to appear. According to Master Gardener Fred Hoffman, the popular conviction that this will result in more tomatoes later is dead wrong. Don't use knives, scissors or clippers when pruning. According to Simply Hydroponics, these can transfer diseases between plants. Always pinch off suckers or leaves with your fingers. Be very gentle when tying, staking, or otherwise supporting your plants. Tomato stems are fragile. Breaking one of those left after pruning will seriously impact your crop.

Things You'll Need

  • Tomato plant of indeterminate or semi-determinate variety


  • Ask the Plant Doctors
  • Simply Hydroponics--Home Grown Tomatoes
  • Hydroponics: Greenhouse Tomato Culture

Who Can Help

  • Growing Hydroponic Tomatoes (interactive step-by-step)
  • The Farmer Fred Rant: Prune Tomato Flowers? No!
Keywords: hydroponic tomato, suckers, fruit truss, indeterminate, semi-determinate

About this Author

Nicole LeBoeuf-Little is a freelancer from New Orleans, writing professionally since 1994. Recent short stories appear on and in Ellen Datlow's anthology "Blood and Other Cravings." She has published articles in "Pangaia Magazine" and eGuides at She holds a Bachelor of Arts in English from University of Washington and attended the professional SF/F workshop Viable Paradise.