Blossom-End Rot: Causes, Symptoms, and Prevention

What blossom-end rot is

Blossom-end rot (BER) is a common physiological disorder that affects fruiting vegetables, especially tomatoes. It starts as a small, sunken brown patch at the blossom end of the fruit and can grow larger as the fruit develops.

Causes

• Primary cause: calcium imbalance in the developing fruit, often triggered by inconsistent watering, rapid fruit growth, or low soil calcium.
• Environmental stress: hot, dry periods, and high salts or fertilizer salts can reduce calcium uptake.
• Root issues: restricted or waterlogged roots can worsen BER.

Symptoms

• Brown, leathery patch at the fruit's blossom end.
• Affected fruit may crack or become inedible as the rot progresses.
• Healthy leaves and stems may not show obvious symptoms.

Prevention and care

• Maintain even soil moisture; drip irrigation and mulching help.
• Avoid water stress; aim for steady moisture and uniform fertilization.
• Test soil pH (generally 6.2–6.8 for most vegetables) and ensure adequate calcium; add lime or gypsum if needed after soil test.
• Limit excessive nitrogen which can promote rapid, weak growth.
• Choose BER-resistant varieties if this is a recurring problem in your garden.
• For containers, ensure proper drainage and regular, consistent watering.

If BER appears and what to do

• Handle affected fruit: remove severely damaged fruit to reduce plant stress.
• Do not rely on calcium sprays to reverse existing BER; prevention is more effective.
• Check irrigation schedule and adjust; consistent watering is key.
• Consider soil testing and adjusting calcium availability for long-term relief.