Tomatoes are sensitive to cold temperatures and have specific tolerances depending on their growth stage:
- Tomato seeds generally will not germinate if soil temperatures are below 10°C (50°F)
- Seedlings and young plants start to suffer cold damage when nighttime temperatures drop below about 12°C (55°F)
- Mature tomato plants can tolerate slightly cooler nights but should not be exposed to temperatures below 10-13°C (50-55°F) for extended periods, as this can cause chilling injury, stunted growth, poor fruit set, and leaf damage
- Tomato fruit can suffer chilling injury if exposed to temperatures around 10°C (50°F) for more than two weeks, or 5°C (41°F) for 6–8 days. Freezing temperatures near 0°C (32°F) cause more severe damage to both plants and fruit
- Ideal growing temperatures for tomatoes are daytime 21-27°C (70-80°F) and nighttime 15-18°C (60-65°F)
- Some cold-hardy tomato varieties exist that can tolerate temperatures at or slightly below 13°C (55°F) and set fruit in cooler climates
In summary, tomatoes tolerate cold temperatures poorly below about 12°C (55°F) at night, and exposure to temperatures below 10°C (50°F) can cause significant damage to seedlings, plants, and fruit. Protection from frost and chilling is essential for healthy tomato growth and fruit development. References:
