Why is there a ring on my Tomato?!

When Lucy stepped out to check her flourishing backyard tomato vines, she noticed something strange: each ripe tomato wore what looked like a scratched halo—an odd ring circling the top, just under the stem. They weren’t blemished enough to toss, but the look was unsettling. Was this a disease? A sign of pests? A nutrient problem? If you’ve noticed a similar ring on your tomatoes, you’re not alone—and it’s not as mysterious as it seems.

Let’s break down what causes this odd tomato ring and how to manage it for healthier, prettier fruit in your garden.

The Tomato “Halo”: What You’re Actually Seeing

That ring around the top of your tomato is usually a condition known as concentric cracking. It appears as a circular, often slightly sunken ring just below the tomato’s stem. While it looks like a scratch or scar, it’s the tomato’s natural response to environmental stress.

What Causes It?

• Rapid Water Uptake: If your tomatoes go from dry to suddenly soaked (after a good rain or inconsistent watering), the inside of the fruit swells faster than the skin can stretch, causing it to split or crack in a ring.
• Over-Fertilization: High nitrogen levels can cause rapid fruit growth, leading to skin stress and cracking.
• Temperature Fluctuations: Hot days followed by cool nights can also trigger uneven growth and skin stress.
• Varietal Susceptibility: Some tomato types are more prone to concentric cracking than others. Heirlooms, for example, tend to have thinner skins.

Tomato Rings vs. Disease: Spot the Difference

Feature	Concentric Cracking	Disease (e.g., Tomato Spotted Wilt)
Shape	Circular ring around stem	Irregular patches or spots
Texture	Smooth or slightly rough	Often sunken, necrotic lesions
Depth	Shallow, not deep into flesh	May affect inner fruit
Spread	Limited to top	Can appear anywhere on fruit

If the rest of the tomato looks healthy and firm, you’re dealing with a physical growth condition—not a disease.

Best Practices to Prevent Tomato Rings

You can’t always control the weather, but you can adjust your gardening habits to reduce the chance of concentric cracking.

1. Water Consistently

• Use drip irrigation or soaker hoses to maintain even soil moisture.
• Water early in the day to reduce evaporation.
• Mulch around the base of your plants to regulate soil moisture.

2. Feed Smartly

• Use a balanced fertilizer (like 5-10-10) rather than high-nitrogen options.
• Add calcium-rich amendments, such as crushed eggshells or lime, to strengthen tomato skins.
• Avoid overfeeding—more nutrients don’t always mean better fruit.

3. Pick at the Right Time

• Harvest tomatoes just as they begin to turn color. Let them ripen indoors to avoid overexposure to sun and rain.
• Check your plants daily during peak season to avoid leaving ripe fruit on the vine too long.

4. Choose Crack-Resistant Varieties

• Opt for hybrid types bred for thicker skins and crack resistance.
• Popular resistant varieties include ‘Celebrity,’ ‘Juliet,’ and ‘Mountain Fresh.’

Quick DIY Nutrient Fix for Stronger Skin

If your tomatoes are already showing signs of skin weakness, try this soil-boosting recipe:

Tomato Skin Strength Mix

• 1 tbsp Epsom salt (magnesium sulfate)
• 1 cup compost tea
• ½ tsp powdered calcium (or crushed eggshells)
• Mix into 1 gallon of water and apply at the base of each plant once every two weeks.

This blend supports better skin elasticity and structure, helping to prevent future cracking.

Further Reading & Resources

• University of Minnesota Extension: Tomato Disorders

A detailed guide to common tomato issues, including cracking and nutrient problems.

• Missouri Botanical Garden: Tomato Fruit Cracking

Offers insight into environmental and genetic causes of tomato cracking.

• The Old Farmer’s Almanac: Tomato Growing Tips

Practical advice on watering, fertilizing, and choosing tomato varieties.

• Clemson Cooperative Extension: Tomato Problems

Covers a wide range of tomato disorders with images and treatment suggestions.

If you find rings on your tomatoes this summer, don’t panic. It’s usually a cosmetic issue you can manage with simple changes to watering and feeding. Your tomatoes are still delicious—and now you’re equipped to keep future crops ring-free.