Tomato Suckers: What They Are & When to Remove Them

Tomato suckers are side shoots that grow in the leaf axils of tomato plants. For indeterminate varieties, removing suckers improves air circulation and directs energy to fruit production, while determinate tomatoes generally don't require sucker removal as they have a fixed growth pattern.

Discover exactly when and how to manage tomato suckers for healthier plants and better harvests. This comprehensive guide reveals science-backed pruning techniques that can increase your tomato yield by up to 25% while reducing disease risk—whether you're growing in containers, raised beds, or garden plots.

Understanding Tomato Suckers: The Basics

Tomato suckers are the shoots that emerge from the axil—the point where a leaf stem meets the main plant stem. These vigorous side shoots look like miniature versions of the main plant and can quickly develop their own branches and fruit clusters if left unchecked.

"Suckers" earned their name because they suck energy from the main plant. While not inherently harmful, unmanaged suckers can create dense foliage that blocks sunlight, reduces air circulation, and diverts energy from fruit production. The University of California Agriculture and Natural Resources confirms that proper sucker management directly impacts both plant health and fruit quality.

Feature	Tomato Suckers	Normal Branches
Location	Leaf axils (between leaf and main stem)	Develop from terminal buds
Growth Pattern	Grow at 45-degree angle from main stem	Grow upward along main stem
Impact if Left	Create secondary stems that compete with main plant	Part of natural plant architecture
Best Removal Size	2-4 inches long	Not applicable

Determinate vs. Indeterminate: The Critical Distinction

Your approach to sucker management depends entirely on your tomato variety's growth habit. This distinction is crucial—applying indeterminate pruning techniques to determinate varieties can significantly reduce your harvest.

Determinate tomatoes (bush tomatoes) grow to a fixed height (typically 3-4 feet), set fruit all at once, and then stop growing. These varieties naturally limit sucker production and don't benefit from pruning. In fact, the University of Minnesota Extension warns that pruning determinate tomatoes can decrease your total yield by removing potential fruit-bearing branches.

Indeterminate tomatoes (vining tomatoes) continue growing and producing fruit throughout the season until killed by frost. These varieties produce abundant suckers that require management. Cornell University's research shows that properly pruned indeterminate tomatoes produce larger, earlier-ripening fruit with fewer disease issues compared to unpruned plants.

The Evolution of Tomato Pruning Practices

Tomato pruning techniques have evolved significantly as horticultural research has advanced. Understanding this timeline helps explain why certain practices work better than others:

• Early 1900s: Commercial growers began single-stem pruning to maximize yield in limited greenhouse space
• 1950s: Research established that removing all suckers increased fruit size but decreased total yield
• 1980s: "Missouri pruning" technique developed—leaving one leaf on removed suckers for shade
• 2000s: Studies confirmed that moderate pruning (2-3 main stems) optimizes both yield and fruit quality
• Present day: Precision pruning based on variety, growing conditions, and harvest goals

When Sucker Removal Makes Sense (And When It Doesn't)

Not all tomato plants need sucker removal. The Texas A&M AgriLife Extension provides clear context boundaries for effective pruning:

Prune indeterminate varieties when:

• Growing in containers or small spaces
• Planting in high-density arrangements
• Experiencing high humidity or disease pressure
• Seeking larger, earlier-ripening fruit

Avoid pruning when:

• Growing determinate varieties
• Planting in extremely hot, sunny climates (suckers provide necessary shade)
• Using organic methods with limited fertilizer (more foliage supports photosynthesis)
• Growing heirloom varieties known for lower productivity

Step-by-Step Sucker Removal Technique

Timing and technique matter more than frequency. Follow these research-backed steps for optimal results:

1. Identify the right time: Remove suckers when they're 2-4 inches long (larger suckers create wounds that invite disease)
2. Choose your method:
   • Pinch method: Use thumb and forefinger to snap off small suckers (best for early season)
   • Pruning shears: Use sterilized shears for larger suckers (dip in 10% bleach solution between cuts)
3. Leave protective leaves: For the "Missouri pruning" technique, leave one leaf on the sucker to provide shade to developing fruit
4. Limit removal: Never remove more than 1/3 of the plant's foliage at once to avoid sunscald
5. Timing matters: Prune early in the morning when plants are turgid for cleaner breaks

Advanced Sucker Management Strategies

Professional growers use specialized approaches based on specific growing conditions:

Container gardening: Restrict indeterminate varieties to one or two main stems. The University of Florida IFAS Extension reports container-grown tomatoes with single stems produce 15-20% larger fruit than unpruned plants.

High-humidity regions: Increase pruning frequency to improve air circulation. Remove suckers weekly during peak growing season to prevent fungal diseases.

Commercial production: Many growers use the "two-stem system"—training the main stem and one strong sucker—to balance yield and plant manageability.

Troubleshooting Common Sucker Issues

Problem: Suckers regrow after removal
Solution: Ensure complete removal at the base. Regrowth indicates some meristematic tissue remains.

Problem: Yellowing leaves after pruning
Solution: You've removed too much foliage at once. Give plants 7-10 days to adjust before further pruning.

Problem: Reduced fruit set after aggressive pruning
Solution: You've removed potential fruit-bearing branches. For future seasons, adopt a more moderate pruning approach.

Final Recommendations for Home Gardeners

Start with moderate pruning—remove only the most vigorous suckers that compete directly with your main stems. The North Carolina State University Extension recommends this balanced approach: "For most home gardeners, removing only the lowest suckers (below the first fruit cluster) provides sufficient benefits without excessive labor."

Remember that perfect pruning technique matters less than consistent observation. Watch how your specific plants respond to different approaches and adjust accordingly. Healthy tomato plants can tolerate a range of pruning intensities—as long as you avoid extreme practices that shock the plant.

When is the best time to remove tomato suckers?

Remove tomato suckers when they're 2-4 inches long, preferably early in the morning when plants are turgid. Larger suckers create bigger wounds that are more susceptible to disease. The University of California recommends weekly checking during peak growing season.

Do all tomato varieties need sucker removal?

No. Indeterminate varieties benefit from sucker removal, but determinate varieties generally don't require pruning. Determinate tomatoes have a fixed growth pattern and removing suckers can actually reduce your total yield by eliminating potential fruit-bearing branches.

Can removing too many suckers harm my tomato plants?

Yes. Removing more than one-third of the plant's foliage at once can cause sunscald on fruit and stress the plant. The North Carolina State University Extension advises moderate pruning—focusing on the most vigorous competing suckers—rather than aggressive removal of all side shoots.

What's the Missouri pruning technique for tomatoes?

Missouri pruning involves removing the growing tip of the sucker but leaving one or two leaves behind. This provides shade to developing fruit while still controlling excessive growth. Developed at the University of Missouri, this technique reduces sunscald risk while maintaining some of the benefits of pruning.

Should I use tools to remove tomato suckers or can I do it by hand?

For suckers under 2 inches, hand removal (pinching) is preferred as it creates a cleaner break. For larger suckers, use sterilized pruning shears dipped in 10% bleach solution between cuts to prevent disease transmission. The University of Florida IFAS Extension recommends against using tools for small suckers as they can damage surrounding tissue.