How to Prune Tomato Plants
Whether you want bigger tomatoes, a healthier plant, or just some peace from an overgrown tangle of vines, pruning your tomato plants is one of the best ways to keep them in check and boost fruit production. But when and why should you prune – and how exactly do you trim them? In this post, I’ll break down how to prune tomato plants step by step so you’ll be snipping with confidence in no time.
Why Prune Tomato Plants?
Pruning helps:
- Direct the plant’s energy toward growing larger fruit.
- Improve air circulation, reducing the risk of tomato diseases like early and late blight.
- Prevent too much shade on developing fruits.
- Keep your plants manageable and easy to harvest.
That said, pruning is totally optional. Tomato plants will still grow and produce fruit even if left unpruned. I’ve skipped pruning on many busy summers and still gotten plenty of yummy tomatoes! You will just end up with a bushier plant and a higher chance of disease in tight spaces, but if you’re strapped for time, don’t stress about it. Regular weeding and watering are way more important!
If you have determinate tomatoes, you should minimize pruning anyway. Speaking of which…
How to Tell If You Have Indeterminate or Determinate Tomatoes
The way you prune depends on the type of tomato you’re growing. I have a complete guide to different tomato varieties, but here are a few basics:
- Determinate Plants: These “bush” types, like Roma, grow to a set size and stop. They produce most of their tomato harvest in one go. Prune these sparingly. Most gardeners only remove damaged leaves or those touching the soil, and generally avoid removing suckers altogether.
- Indeterminate Plants: These “vining” types, such as Cherry Tomatoes or Big Beef, keep growing and producing new flowers until the first frost. They need regular pruning to control their size and encourage fruit production.
Quick Reference Chart
| Tomato Type | Pruning Needed? | Why It Matters |
|---|---|---|
| Determinate | Minimal – only damaged or low leaves | Too much pruning reduces overall yield |
| Indeterminate | Regular – remove suckers and side shoots | Improves air circulation and directs energy to fruiting |
When to Prune Tomato Plants for Healthier Growth
The best time to prune tomatoes is in the early morning on a dry day. This gives the plant time to heal before nighttime, reducing the risk of fungal diseases.
How to Prune Tomato Plants
When your plant is ready to prune, start by using clean tools or your bare hands to prevent spreading diseases. Disinfect between plants to avoid transmitting pathogens.
1. Early Growth: Tomato Seedlings to First Flowers
- When your tomato seedlings have a strong main stalk, pinch off the lower leaves near the soil to prevent the spread of soil-borne diseases.
- Look for tomato suckers, which are new branches that sprout in the space between the main stem of the plant and a branch (often at diagonal angles). These little guys sap energy from the plant.
- After the first flower clusters appear, remove any suckers below them to focus the plant’s energy on growing fruit.
Here’s a helpful guide that will show you exactly how it’s done:
2. Midseason Pruning: Early to Late Summer
- For indeterminate varieties, remove side shoots and suckers regularly. Removing all suckers creates a single-stem plant; leaving some forms double or triple stems, which can increase yield but require stronger support.
- Suckers under 2 inches can be pinched off by hand; larger ones should be snipped with pruners to avoid damaging the plant.
- Thin out the lower branches and center foliage—removing about one-third of dense center leaves—to improve air circulation and sun exposure.
- Remove leaves up to 12 inches from the soil line to prevent splashing soil from spreading blights and other diseases.
3. Late in the Season: Prepping for the First Frost
- A few weeks before the first frost, remove the top of the plant and any new flowers. This helps the plant focus on ripening existing green tomatoes instead of wasting energy on new branches.
- Stop heavy pruning 1–2 weeks before your expected harvest to help prevent sunscald on ripening fruit.
How to Prune Tomatoes in Different Growing Setups
In a Tomato Cage
If your plants are in a tomato cage, prune the side branches to keep the plant growing upward. This helps maximize the space inside the cage and prevents overcrowding.
On an Overhead Trellis System
Guide the main branches up the trellis, and remove all suckers. Letting the plant grow vertically saves space and reduces shade on the lower fruit clusters.
Common Tomato Pruning Mistakes to Avoid
- Removing too much: Plants need leaves for photosynthesis. Don’t go overboard; removing one or two suckers when you begin pruning is more than enough.
- Pruning at the wrong time: Avoid pruning during wet conditions to reduce the risk of fungal infections.
- Ignoring plant health: Always remove leaves showing signs of fungal diseases or pests.
- Pruning determinate tomatoes too aggressively: Stick to removing damaged or soil-touching leaves only.
- Removing healthy fruiting stems: If a long branch has fruit, consider staking it rather than removing it.
FAQ: Pruning Tomato Plants
You don’t have to, but it certainly helps, especially for indeterminate types. Container-grown tomatoes benefit from pruning to manage size and improve airflow.
Focus on removing suckers, lower leaves touching the soil, and any diseased or damaged foliage. For indeterminate plants, also thin the center to improve airflow.
Remove all suckers to train the plant into a single stem, which channels energy to fewer but larger fruits. Provide sturdy support and remove lower and center leaves to boost air circulation and reduce disease.
Happy Tomato Growing!
Pruning, while not required, can boost your tomato crop when done properly. Follow these tips and your plants will be off to a great start!
Looking for more tomato tips? I have a complete tomato care guide, along with lots more on…
