Blossom End Rot in Tomatoes: The Surprising Fix Every Gardener Needs

Key Takeaways

  • Recognize the Signs: Dark spots on the fruit’s bottom indicate blossom end rot.
  • Understand the Causes: Calcium deficiency, inconsistent watering, and poor soil conditions are the main culprits.
  • Prevention is Key: Ensure proper soil pH, consistent watering, and good air circulation.
  • Treat Effectively: Use organic liquid plant food and lime supplements for calcium deficiency.

Blossom End Rot In Tomatoes: Identification, Prevention & Treatment

Are your tasty tomatoes turning black on the bottom? Blossom end rot in tomatoes causes large, tough, round, brown, or black spots on the ends of the fruit. While these affected fruits are lost, you can save the rest of your crop.

What is Blossom End Rot?

Blossom end rot in tomatoes (Solanum lycopersicum), also known as tomato bottom rot, can lead to significant fruit loss. The tough brown to black spots that appear at the fruit’s bottom end are not caused by germs but by a lack of nutrients, specifically calcium.

But don’t worry – this problem is fixable! Read on to learn how to treat blossom end rot and prevent it in the future.

Signs of Blossom End Rot in Tomatoes

Blossom end rot occurs when the growing fruit lacks calcium, not due to pests or diseases. This can affect many large-fruit plants, including eggplants (Solanum melongena), peppers (Capsicum annuum), watermelons (Citrullus lanatus), and zucchini (Cucurbita pepo).

Blossom end rot in tomatoes

The main sign is dark spots at the end of the fruit, which later sink in and dry out. Severe cases make it look like the tomatoes rot while still on the plant. You can still eat fruit with minor blossom end rot by cutting off the bad part, but be cautious, as these spots can harbor mold or bacteria.

Causes of Blossom End Rot in Tomatoes

Blossom end rot results from insufficient calcium in the affected parts of the plant. Calcium is essential for building cell walls and moves from the roots to the leaves and fruit. Calcium deficiency can occur due to soil conditions or inconsistent water availability.

  1. Soil pH: Acidic soils can trap calcium, making it difficult for plants to absorb it through their roots.
  2. Watering: Inconsistent watering can lead to calcium deficiency. Plants move nutrients through a process called transpiration, which requires adequate soil moisture.
  3. Rapid Growth: Fast-growing plants with abundant leaves can use available calcium, leaving insufficient amounts for fruit development.
  4. Greenhouse Conditions: High humidity and stagnant air in greenhouses reduce transpiration, exacerbating nutrient deficiencies. Large tomato varieties are more prone to blossom end rot due to their rapid growth and higher calcium needs.

Treatment and Prevention

The best way to address blossom-end rot is through prevention. Proper soil preparation, consistent watering, and good air circulation are key. If you already see signs of blossom end rot, remove the affected fruit and address the calcium deficiency.

  • Watering: Water your plants consistently, keeping the soil moist but not waterlogged.
  • Air Circulation: Prune your plants to ensure good airflow. In greenhouses, fans and open windows are used to increase air movement.
  • Nutrient Supplements: If your soil lacks nutrients, use an organic liquid plant food with micronutrients or a liquid calcium supplement. Products like Plantura Liquid Tomato Food provide essential nutrients, including calcium.
  • Soil Preparation: Before planting tomatoes, amend the soil with calcium and adjust low pH using lime products. Use high-quality, long-lasting organic granular plant food, such as Plantura Tomato Food, to provide slow-release nutrients throughout the growing season.
  • Avoid Home Remedies: Some suggest using powdered milk to treat blossom end rot, but it’s better to use lime supplements like gypsum, calcium carbonate, or limestone, which offer more readily available calcium.

FAQs about Blossom End Rot in Tomatoes

Can I treat tomatoes that already have Blossom End Rot?

Unfortunately, once a tomato has Blossom End Rot, the affected part of the fruit cannot be healed. However, you can remove the damaged fruit to focus the plant’s energy on healthy tomatoes.

Is Blossom End Rot in tomatoes harmful to humans?

No, Blossom End Rot is not harmful to humans. The unaffected part of the tomato is safe to eat, but the affected portion should be removed and discarded.

Can other plants get Blossom End Rot?

Yes, Blossom End Rot can also affect other plants like peppers, eggplants, and squash, as they, too, can suffer from calcium deficiencies.

Does soil type affect the occurrence of Blossom End Rot?

Yes, sandy or heavy clay soils can exacerbate the problem. Ensuring well-drained, loamy soil rich in organic matter helps improve calcium availability and water retention.

How often should I water my tomatoes to prevent Blossom End Rot?

Water your tomatoes consistently, aiming for 1-2 inches of water per week. It’s better to water deeply and less frequently than shallowly and often.

Can foliar sprays help in preventing Blossom End Rot?

Calcium foliar sprays can help if applied early in the growing season but are ineffective once the fruit is affected. It’s best to focus on soil and watering practices for long-term prevention.

What role does pH play in preventing Blossom End Rot?

Soil pH affects nutrient availability, including calcium. Tomatoes thrive in slightly acidic soil with a pH of 6.2-6.8. Testing and adjusting soil pH can help prevent Blossom End Rot.

Can using Epsom salt help with Blossom End Rot?

Epsom salt (magnesium sulfate) is ineffective for Blossom End Rot, as it does not supply calcium. Instead, focus on ensuring adequate calcium levels in the soil.

 Is it possible to overwater tomatoes and cause Blossom End Rot?

Overwatering can lead to waterlogged soil, which hinders calcium uptake by the plant roots, potentially causing Blossom End Rot. Aim for consistent, moderate watering.

Do different tomato varieties have different susceptibility to Blossom End Rot?

Yes, some tomato varieties are more resistant to Blossom End Rot than others. Heirloom varieties, in particular, may be more susceptible, while certain hybrid varieties are bred for resistance.

Can I use crushed eggshells to prevent Blossom End Rot?

Crushed eggshells can provide a slow-release source of calcium, but they break down slowly. It’s more effective to use lime or gypsum for quicker results.

How do temperature fluctuations affect Blossom End Rot?

Rapid temperature changes can stress tomato plants and affect calcium uptake, increasing the risk of Blossom End Rot. Mulching can help regulate soil temperature.

Is there a way to revive plants suffering from Blossom End Rot?

While affected fruits cannot be revived, you can improve watering and soil conditions to prevent further occurrences. Removing affected fruits can help the plant focus on producing healthy tomatoes.

Can container-grown tomatoes suffer from Blossom End Rot?

Yes, container-grown tomatoes are also susceptible. Ensure the potting mix has good drainage and consistent moisture, and consider adding calcium supplements if needed.

How does fertilization impact Blossom End Rot in tomatoes?

Over-fertilization, especially with high-nitrogen fertilizers, can exacerbate Blossom End Rot by promoting rapid foliage growth over fruit development. Use a balanced fertilizer and avoid overuse.

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