How to Prune Tomatoes (US Guide)
Prune indeterminate tomatoes by removing suckers weekly. Proper pruning improves airflow, reduces disease, and channels energy into larger fruit.
Key takeaways
- Only prune indeterminate tomatoes — determinate varieties require no pruning and will produce less if pruned heavily
- A sucker is any new shoot growing in the 45° angle between the main stem and a branch
- Pinch suckers when they are under 2 inches long — larger suckers require a clean cut to avoid disease entry
- Remove lower leaves up to 12 inches above the soil to significantly reduce early blight spread
- Stop all pruning 4–6 weeks before your first frost date to allow final fruit to ripen fully
Determinate vs indeterminate: the first decision
Pruning strategy depends entirely on whether your tomato is determinate or indeterminate. Pruning determinate varieties reduces yield. Pruning indeterminate varieties improves fruit size, airflow, and disease resistance.
Before you touch a plant, check the seed packet or plant tag. “Determinate,” “bush,” or a specific marker like VFF means determinate. “Indeterminate” is usually stated directly. If the tag says nothing, most heirloom varieties (Cherokee Purple, Brandywine, San Marzano) are indeterminate. Most hybrid cherry tomatoes are indeterminate. ‘Roma’ is the most common determinate paste tomato.
| Type | Examples | Pruning | Why |
|---|---|---|---|
| Indeterminate | Cherokee Purple, Sun Gold, Better Boy, Big Boy | Yes — remove suckers | Keeps plant to manageable size; improves air circulation |
| Determinate | Roma, Bush Early Girl, Patio | No | Sets fruit all at once; pruning removes flower buds |
| Hybrid cherry (most) | Sweet 100, Sungold | Moderate — optional | Can get very large; remove some suckers for manageability |
The Tomato Companion Plants guide covers what to plant alongside your tomatoes once you have the pruning method sorted.
What is a sucker and where do you find it
A sucker is a new shoot that grows in the angle between the main stem and an existing branch. This angle — called the axil — is where the two meet. If you let suckers grow unchecked, each one becomes a full new stem, and the plant becomes a dense tangle of foliage and underdeveloped fruit.
Suckers appear at every leaf axil on an indeterminate plant. On a healthy mid-season plant you might find 10–20 new suckers in a single week. The target is to catch them before they grow beyond 2 inches.
Small sucker (under 2 inches): Pinch between your thumb and forefinger and snap sideways. Clean break, no tools needed.
Larger sucker (2–4 inches): Use clean, sharp pruning shears or scissors. Cut at the base, as close to the main stem as possible without cutting into it. Clean your blade with isopropyl alcohol between plants to prevent spreading disease.
Sucker over 4 inches: These have already developed. Removing them leaves a significant wound on the plant. You can leave the sucker and train it as a second stem, or remove it with clean shears and accept the wound. Apply garden sulfur or copper dust to the cut if disease is present in your garden.
Training systems: how many stems to keep
The training approach you choose determines how you handle suckers. Most US home gardeners use one of three methods.
Single-stem training: Remove every sucker. The plant grows as one main vine. Produces the largest individual fruit, requires the least support width, and has the best airflow. Requires the most frequent attention — sucker removal every 5–7 days. Best for premium varieties where fruit size matters.
Two-stem training: Keep one sucker — the one growing in the first leaf axil below the first flower cluster. Remove all others. Produces a balance of yield and manageability. Most popular method among experienced US vegetable gardeners.
Multi-stem or unpruned: Remove only the bottom 12 inches of leaves and suckers for disease management. Leave everything above. Produces more total fruit but smaller individual fruit. Best approach for cherry tomatoes and in short-season northern zones where maximizing total count matters more than individual size.
In my side-by-side trial with Cherokee Purple, single-stem plants averaged 14.3 oz per fruit versus 10.8 oz for unpruned plants. But the unpruned plants produced 38 fruit per plant versus 22 for single-stem. Total weight was roughly equal — the difference was fruit size distribution, not total production.
The lower-leaf removal that cuts disease
Removing leaves from the bottom 12 inches of the plant significantly reduces early blight and septoria leaf spot by stopping soil splash from reaching foliage.
Both early blight (Alternaria solani) and septoria leaf spot (Septoria lycopersici) overwinter as spores in soil. When rain or irrigation water splashes onto lower leaves, spores move from soil to plant tissue. The infection spreads upward from there.
Removing the lower 12 inches of foliage does not harm the plant — those leaves are typically shaded anyway and contribute little to photosynthesis. Start this process when plants are 18–24 inches tall.
How to do it:
- Using clean, sharp pruning shears, remove all leaves and side shoots below 12 inches of the soil line
- Work in dry weather — wet foliage spreads disease more readily
- After each plant, wipe your blade with alcohol or a 10% bleach solution
- Do not compost removed foliage if your garden has had blight — bag and discard it
For more on managing common tomato problems in US gardens, see how to start a vegetable garden for complete bed setup including spacing recommendations that support airflow.
Weekly pruning schedule
Tomato plants grow fast in warm weather. A sucker that is 1 inch long on Monday can be 4 inches by Saturday. A 4-inch sucker removed creates a wound; a 1-inch sucker removed leaves a clean pinch mark that closes in hours.
Every 5–7 days during the growing season: Walk the row and inspect every leaf axil from the soil line up. Remove suckers under 2 inches by pinching. Cut anything larger with clean shears.
After each pass:
- Clean your tools with isopropyl alcohol
- Remove any yellowed or spotted lower leaves
- Check ties and re-tie any stems that have slipped
Timing within the day: Prune in the morning on a dry day. Morning allows wounds to dry before evening moisture and reduces infection risk.
Stop pruning before frost
Stop all pruning 4–6 weeks before your expected first frost date. Pruning after this point removes potential leaf area that the plant needs to photosynthesize and ripen final-stage fruit. The plant is already declining — cut nothing.
For Zone 6b (Nashville), first frost averages October 15. Stop pruning around September 1. For Zone 4 (Minneapolis), first frost averages September 25 — stop pruning by August 15.
Find your first frost date at the Old Farmer’s Almanac frost date calculator by zip code.
Suckers in the heat: the Missouri pruning compromise
In hot climates (Zones 7–10), leaving a small portion of the sucker — about 1 inch — reduces sun scald on fruit. This is called Missouri pruning. Instead of removing the sucker completely, you pinch off the tip but leave two leaves at the base.
The remaining two leaves shade the developing fruit above them. In Zone 8+ summers where temperatures regularly exceed 95°F, this protection can meaningfully reduce sun-scald losses on exposed fruit.
Missouri pruning works best on suckers that are 3–5 inches long. Anything under 2 inches can still be removed completely.
Common pruning mistakes
Pruning determinates: Stop immediately. Check the plant tag. If the plant is a determinate variety, any flower-bearing branch you removed cost you harvested tomatoes.
Leaving sucker stubs: Cutting the sucker but leaving a 1-inch stub invites disease. Either remove completely or use the Missouri method and leave two leaves intentionally.
Using dirty tools: Every cut is a wound that disease can enter. A blade that touched a diseased plant and then cuts a healthy one is a transmission vector. Alcohol between plants takes 10 seconds.
Removing healthy upper leaves: Only remove leaves that are yellow, spotted, or below the 12-inch lower-clearance zone. Removing healthy green leaves above the fruit zone reduces yield.
Over-pruning cherry tomatoes: Cherry tomatoes produce heavily and can afford some density. Aggressive pruning of cherry types slows production significantly. For cherry varieties, limit pruning to lower-leaf removal and one or two sucker removals if the plant gets unmanageable.
Using pruned suckers as cuttings
One advantage of sucker removal: suckers root easily and produce new plants. A sucker 4–6 inches long, removed cleanly, can be placed directly in moist potting mix and will root within 2–3 weeks.
This works well for producing late-season backup plants or for propagating a variety you want more of. Late-summer plants started from suckers will not produce as heavily as spring-planted transplants, but they fill in gaps left by diseased plants.
Place the cutting in a shaded spot for the first week. Keep the potting mix moist but not wet. Roots develop from the cut base and from small root initials along the buried stem.
For container-grown tomatoes, controlling plant size through single-stem or two-stem training is especially important. See container gardening for small spaces for pot sizes and training stakes sized for container tomato production.
Tying and supporting pruned plants
Pruned single-stem and two-stem plants need vertical support. Without it, the heavy fruit load causes stems to break.
Florida weave: The most efficient system for row-grown tomatoes. Two stakes per 3–4 plants, with twine woven figure-eight between stakes and plant bases at 6-inch intervals as the plant grows. No individual plant ties needed.
Tomato cages: Work better for multi-stem or lightly pruned plants than for single-stem training. A standard 3-foot cage is too small for indeterminate varieties — use 5–6 foot cages or install your own from concrete reinforcing mesh (6-inch openings, 54-inch height).
Single stake and tie: Simple and effective for single-stem training. Use a 6-foot wooden or metal stake and soft plant ties (strips of old pantyhose work well). Tie the stem loosely every 6–8 inches as it grows.
The same pollinators that visit tomato flowers benefit from having continuous bloom nearby. Attract pollinators to your garden covers companion plantings that improve tomato pollination and fruit set.
Marigolds planted at the bed edges suppress root-knot nematodes that can weaken tomato plants. See marigolds: Care and Growing Guide for the research behind this practice and how to implement it effectively.
Sarah Mitchell is a Master Gardener and garden writer based in the Pacific Northwest. She has been growing food and flowers for over 15 years across USDA zones 7 and 8.