Tomato Suckers Explained: What They Are & How to Manage Them

Suckers on a tomato plant are the small shoots that grow in the axils between the main stem and leaf branches. These secondary growths compete with the main stem for the plant's energy, potentially reducing fruit size and yield. Proper sucker management is essential for maximizing harvests from indeterminate tomato varieties.

Understanding Tomato Suckers: Your Path to Healthier Plants

When you're growing tomatoes, recognizing and managing suckers is one of the most important techniques for ensuring robust plants and abundant harvests. But what exactly are these mysterious 'suckers' that gardening guides keep mentioning? Let's break it down with practical, science-backed information you can use immediately in your garden.

What Are Tomato Suckers? Clear Identification Guide

Tomato suckers—also called axillary shoots—are the small, secondary growths that emerge from the leaf axils, the V-shaped junction where a leaf stem meets the main plant stem. These shoots appear as miniature versions of the main stem, complete with their own leaf sets and potential flower clusters.

Here's how to spot them:

• Look for new growth emerging at a 45-degree angle from the main stem
• They typically appear between existing leaves and the central stalk
• Young suckers are soft, flexible, and lighter green than mature growth
• They develop their own leaf sets as they grow larger

Unlike the main stem which grows vertically from the top, or fruiting branches that develop flowers, suckers represent potential new stems that would create a bushier, more complex plant structure if allowed to grow unchecked.

Why Suckers Matter: The Science Behind Plant Energy Distribution

Understanding why tomato suckers affect your harvest requires knowing how plants allocate their resources. When a sucker develops into a full stem, it creates what horticulturists call "competitive growth"—multiple stems competing for the same pool of water, nutrients, and photosynthetic energy.

Plant Resource	With Suckers Removed	With Suckers Left
Energy Allocation	Directed to fruit production	Divided between stems and fruit
Fruit Size	Larger, more uniform	Smaller, variable size
Ripening Time	More consistent	Staggered, extended
Disease Risk	Lower (better air circulation)	Higher (dense foliage)

Research from the University of California Agriculture and Natural Resources shows that properly managed indeterminate tomato plants can produce up to 30% larger fruit when suckers are selectively removed, as the plant's energy focuses on fewer, stronger fruiting branches rather than maintaining multiple stems. [Source: UC ANR Publication 8511]

Determinate vs. Indeterminate: Why It Changes Your Sucker Strategy

Not all tomato varieties respond the same way to sucker removal. The critical distinction lies between determinate and indeterminate growth habits:

• Determinate varieties (bush tomatoes) grow to a fixed height, set fruit all at once, and then stop growing. These varieties rarely require sucker removal as their growth pattern is naturally compact.
• Indeterminate varieties (vining tomatoes) continue growing and producing fruit throughout the season until killed by frost. These varieties benefit significantly from strategic sucker management to maintain productivity and plant health.

Common determinate varieties include 'Roma', 'Celebrity', and 'Bush Early Girl', while popular indeterminate types include 'Beefsteak', 'Cherokee Purple', and 'Sun Gold'.

When and How to Remove Tomato Suckers: Step-by-Step Guide

The timing and technique of sucker removal dramatically affects your results. Follow these science-backed steps for optimal plant health:

1. Identify the right time: Remove suckers when they're 2-4 inches long. Smaller suckers heal faster, while larger ones create bigger wounds that invite disease.
2. Choose your method:
   • Pinch method: For young suckers, use your thumb and forefinger to gently pinch and twist the sucker away from the main stem. This creates a small wound that heals quickly.
   • Tool method: For larger suckers or if you have sensitive hands, use clean, sharp pruners. Make a clean cut close to the main stem without damaging it.
3. Decide what to keep: For most indeterminate varieties, maintain 1-3 main stems. Remove all other suckers consistently.
4. Timing matters: Perform sucker removal in the morning when plants are hydrated and wounds heal fastest. Avoid working with wet plants to prevent disease transmission.

Pro tip: After removing suckers, wash your hands before handling other plants to prevent potential disease spread. The University of Florida IFAS Extension recommends sanitizing tools between plants when disease pressure is high in your area. [Source: UF/IFAS HS100]

When to Keep Suckers: Strategic Exceptions to the Rule

While removing suckers generally benefits indeterminate tomatoes, there are specific situations where keeping some suckers makes sense:

• Container gardening: In limited-space containers, allowing one additional sucker can increase overall yield without creating excessive density.
• End-of-season boost: In the last 4-6 weeks before first frost, letting some suckers grow can produce additional late-season fruit.
• Shade protection: In extremely hot climates, a few strategically placed suckers can provide necessary shade to prevent sunscald on ripening fruit.
• Recovery from damage: If your main stem gets damaged, a healthy sucker can be trained to become the new primary stem.

What to Do With Removed Suckers: Beyond the Compost Bin

Don't automatically toss those removed suckers! They have several valuable uses:

• Propagation: Healthy suckers 4+ inches long can be rooted in water or soil to create new tomato plants. Remove the lower leaves, place in water, and roots should appear in 7-10 days.
• Compost material: Add to your compost pile as green material (high in nitrogen).
• Pest monitoring: Examine removed suckers for signs of pests or disease that might affect the main plant.

According to Cornell University's Garden-Based Learning program, sucker propagation has about a 70% success rate for creating new plants when done properly during the active growing season. [Source: Cornell Garden-Based Learning]

Avoiding Common Sucker Management Mistakes

Even experienced gardeners sometimes make these critical errors when handling tomato suckers:

• Over-pruning: Removing too many leaves along with suckers reduces photosynthesis capacity. Never remove more than 1/3 of the plant's foliage at once.
• Pruning determinate varieties: These bush-type tomatoes don't benefit from sucker removal and may actually produce less fruit if pruned excessively.
• Removing too late: Waiting until suckers are large creates bigger wounds that take longer to heal and increase disease risk.
• Using dirty tools: Always sanitize pruners between plants to prevent disease transmission.

Remember that proper tomato sucker management isn't about eliminating all side growth—it's about strategic redirection of plant energy to maximize your harvest while maintaining plant health throughout the growing season.

Do all tomato varieties produce suckers?

Yes, all tomato plants produce suckers, but how they affect the plant depends on whether the variety is determinate or indeterminate. Indeterminate varieties produce continuous suckers throughout the growing season, while determinate varieties produce fewer suckers and stop growing at a certain height.

Can removing too many suckers harm my tomato plant?

Yes, excessive sucker removal can harm your plant by reducing its photosynthetic capacity. Removing more than one-third of the plant's foliage at once stresses the plant and can lead to sunscald on fruits. Always maintain enough leaf cover to protect developing fruit from direct sun exposure.

When is the best time of day to remove tomato suckers?

The best time to remove tomato suckers is in the morning when plants are fully hydrated. This allows wounds to heal more quickly. Avoid working with wet plants as this can spread diseases. Never prune during the heat of the day as this stresses the plant when it's already under water pressure.

Can I grow new tomato plants from removed suckers?

Yes, healthy suckers 4-6 inches long can be propagated to grow new plants. Remove the lower leaves, place the cutting in water or moist potting mix, and roots should develop within 7-10 days. This works best with suckers from indeterminate varieties during the active growing season.

How often should I check my tomato plants for suckers?

Check indeterminate tomato plants for new suckers every 5-7 days during peak growing season. Suckers grow quickly, and removing them when they're small (2-4 inches) creates less stress on the plant and heals faster. During hot summer months, you may need to check more frequently as growth accelerates.