What’s the deal with pruning my tomatoes?
Tomato plants have one goal… grow. And grow. And then grow some more.
Without pruning and trellising, many tomato plants can turn into a tangled jungle of stems and leaves that will probably break in a frustrated attempt to create order.
This is where pruning comes in!
Determinate vs. Indeterminate Tomatoes
Determinate tomatoes, I’ve also heard them called bush tomatoes, have a maximum height, produce most of their fruit in a relatively short time period, and then slow down in growth and fruiting. Roma tomatoes are determinate.
For these, light pruning is your best bet because removing too much foliage can actually reduce your harvest as they need that photosynthesis power for their bumper crop tendencies.
Indeterminate tomatoes, or vine tomatoes, are the ones that can feel a bit chaotic. They continue growing, flowering, and producing fruit until frost shuts them down.
Popular examples include Sungold - a favorite!
Regular pruning helps keep plants manageable, improves airflow, and directs energy toward fruit production rather than branch and leaf production.
Why should I Prune?
Pruning will:
Improve air circulation
Reduce the risk of fungal diseases
Increase sunlight penetration
Make harvesting easier
Support larger, healthier fruit
Keep plants from becoming an unruly tomato thicket
What should I Prune?
Suckers! Tomato suckers are small shoots that grow in the space between a main stem and a branch. Imagine you’re parting curtains to see if the coast is clear to run outside in just your knickers for some herbs. Your head is the sucker when you part the curtains. Does that make sense?
Anyways, they start tiny but can quickly become full-sized stems with leaves, flowers, and fruit. The fruit when it’s on suckers and main branches can become small, and not very tasty.
How to Spot a Sucker
Look for a "V" where a branch meets the main stem.
If a new shoot is growing right out of that V-shaped joint, that's a sucker.
How to Prune Indeterminate Tomatoes
Start pruning when plants are about 12 to 18 inches tall and well established.
Prune in the morning as plants are well hydrated, temperatures are cooler, and any pruning wounds have time to dry during the day. Pruning in the rain should also be avoided. Dry mornings are best.
Step 1: Remove Lower Leaves
As plants grow, remove leaves that touch the soil or sit within 6 to 12 inches of the ground.
Step 2: Remove Excess Suckers
One main stem: Maximum airflow and easiest maintenance.
Two or three stems: Slightly larger plants with potentially higher overall yields.
Remove unwanted suckers regularly throughout the season.
Step 3: Thin Dense Growth
If the center of the plant becomes crowded, selectively remove a few leaves to improve airflow and light penetration.
Step 4: Top Plants Late in the Season
About 4 to 6 weeks before your first expected frost, consider removing the growing tip of indeterminate plants.
This encourages the plant to focus on ripening existing fruit rather than producing new flowers that won't have time to mature.
How to Prune Determinate Tomatoes
Less is more.
For determinate varieties:
Remove damaged or diseased leaves
Remove leaves touching the soil
Lightly thin crowded growth if needed
Leave most suckers alone
Heavy pruning can reduce the total number of tomatoes you'll harvest.
Common Tomato Pruning Mistakes
Pruning too much - Never remove more than about one-third of the plant at a time.
Ignoring diseased foliage - Yellow, spotted, or diseased leaves should be removed promptly and discarded (best to burn or bag rather than compost diseased plant material).
Using dirty tools - Wipe pruner blades with rubbing alcohol when moving between plants, especially if disease is present.
A Few More Tomato Tips…
Support plants with cages, stakes, or trellises to improve airflow and keep fruit off the ground.
Water deeply and consistently to prevent cracking and blossom-end rot.
Mulch around plants to retain moisture and reduce soil splash.
Fertilize regularly according to your tomato variety and growing conditions.
Harvest often to encourage continued flowering and fruit production.
As you venture off to prune, don't overthink it. Tomatoes are surprisingly forgiving. A few minutes of pruning every week can help turn a sprawling tomato jungle into a productive, easy-to-manage marinara factory.