Tomato blossom end rot shows up as dark, sunken, leathery spots on the blossom end of fruit. It is a calcium-related disorder, but the treatment is usually water and stress management, not dumping calcium products into the soil.
Affected fruit will not heal. The goal is to help new fruit develop normally.
For the calcium explanation, read Why Tomato Plants Need Calcium.
Last updated: June 6, 2026.
Quick Answer
Remove badly affected fruit, water consistently, mulch, avoid root damage, avoid excess nitrogen, test soil pH and nutrients, and use calcium amendments only if a soil test or container program indicates they are needed.
What Blossom End Rot Looks Like
Symptoms:
- tan, brown, or black spot on blossom end
- sunken leathery tissue
- damage begins on young green fruit
- often worst on first fruit cluster
- can affect tomatoes, peppers, squash, and watermelons
Do not confuse it with insect feeding, sunscald, or fungal fruit rot.
Immediate Treatment Steps
- Remove severely affected fruit.
- Check soil moisture 4 to 6 inches deep.
- Water deeply and consistently.
- Add mulch if soil is bare and warm.
- Stop heavy nitrogen feeding.
- Avoid hoeing near roots.
- Check container size and drainage.
- Test soil if the problem repeats.
The next flush of fruit may improve after stress is corrected.
Why Calcium Sprays Often Disappoint
Calcium must reach developing fruit through the plant’s water stream. Sprays may not move enough calcium into fruit tissue to fix the disorder. Soil calcium products also fail if the real problem is water fluctuation.
Better prevention:
- steady root moisture
- healthy root system
- correct pH
- balanced fertilizer
- mulch
- no severe root pruning
Containers Are High Risk
Tomatoes in pots are prone to blossom end rot because containers dry quickly.
Use:
- large containers
- quality potting mix
- consistent irrigation
- complete fertilizer
- mulch on container surface
- saucers only if drainage is managed carefully
Small pots are a common hidden cause.
What Not to Do
Avoid:
- adding Epsom salt
- assuming eggshells will solve it quickly
- over-liming without a pH test
- adding bone meal in high-phosphorus soil
- fertilizing dry plants
- letting plants wilt repeatedly
- stripping leaves aggressively
Read Epsom Salt for Plants: Useful or Myth? before using magnesium products.
FAQ
Can I eat tomatoes with blossom end rot?
You can cut off the affected part if the rest of the fruit is sound, but badly damaged fruit is often poor quality.
Will blossom end rot spread?
It is not an infectious disease. It does not spread like a fungus, but the same stress can affect multiple fruits.
Should I remove affected tomatoes?
Remove badly affected fruit so the plant puts energy into healthier fruit.
Related Reading
- Why Tomato Plants Need Calcium
- Best Fertilizer for Tomatoes
- Tomato Leaves Curling: Causes and Fixes
- How Often to Water Tomatoes in Raised Beds