How to prune tomatoes
What tomatoes to prune. Indeterminant tomatoes are the ones you want to prune the most.
Determinant plants you don’t want to prune much, maybe not at all, other than the leaves close to the ground.
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Indeterminant tomatoes—These plants will continue to grow taller and keep producing fruit till they plant freezes. I have had sun gold tomato plants that were over 15 feet tall by the end of the season and still going.
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Determinant tomatoes—These plants will grow to a certain height and stop. They will produce most of their fruit in a few weeks’ time and then slow down considerably.
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Why prune tomatoes?
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Prune to keep at a manageable height.
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Prune to have 3 or 4 strong stems.
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Prune each to about the same length.
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Prune all lower stems and leaves so no leaves are touching the ground.
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Prune to thin so the plant gets good air circulation.
Make sure your pruner is clean of germs from other plants. You don’t want to transfer any disease from other plants. Use rubbing alcohol on the shears before using them and after you cut any plant that may be diseased.
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Prune the suckers. The suckers are the stems that grow out of the V section of the plant. Between the main stem and the side stems. You can toss them in the compost or what is cool is these are viable plants.
You can replant the suckers and grow whole new tomato plants. If you will not save the suckers, you can prune them when they are a couple of inches long. You can pluck them off with your finger.
If you are going to plant them as new plants, let them get four to six inches long. Tomatoes are special for planting cuttings. You can stick them directly into dirt and they will grow roots and become a full plant. Push it into the dirt up to the leaves on the sucker.
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Do your first pruning when the plant is about 18 inches tall. Wait until the first flowers appear. If you are going to cut off the top to manage the size of the plant. Cut it off just above a leaf node. Leave those leaves to protect the fruit for sun damage. Pruning the top is especially important when you are growing large plants Indoors.
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Keep the plant pruned, so it fits the height of the support cage you have. Unless you are using the string support method, this is the best practice. This will force the plant to produce more and larger tomatoes on the shorter plant. All the energy of the plant will go into what is there and not trying to support a 10-to-15-foot plant.
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To top the plant, cut it off just above the fruit or flower cluster so the flowers or fruit are the top of the plant. Check weekly and take off all suckers near the top. You can leave some suckers lower on the plant if they get big and you don’t want to take them off. They will grow fruit.
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When you get to within 45 days of the first frost, you want to prune the plant well to focus the energy and producing the most fruit before the end of the season.
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One tip of something I like to do to extend the season for getting good tomatoes is. Take suckers off and put them in a six-inch pot to get going. Repot them into a five gallon grow bag and get them going. They will turn into good plants quickly and when it gets later in the season and you get frost, bring them into your garage when it’s going to frost and put them back out in the sun when it warms up.
You can get tomatoes for a month longer in the season by doing this. It works.
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