Extreme temperature effects on tomato and pepper crops
Learn about the impact of freezing and chilling temperatures on tomato and pepper plants.
Freezing and chilling injury in tomato and pepper plants
Low soil temperatures can stunt plant growth and prevent root development. Temperatures below 10°C during flowering can interfere with pollination and lead to catfacing on fruit.
Freezing injury in tomato and pepper plants
Frost occurs when the temperature drops to 0°C at 1.5 meters above the ground, but this does not always result in damage to crops.
The temperature at which freezing occurs depends on factors, such as:
- plant species and variety
- plant vigor
- soil conditions
- surface cover
- duration of the freezing temperature
- thawing conditions
- cloud cover
- wind conditions
Peppers are more sensitive to freezing temperatures than tomatoes and can be injured or killed by a light frost.
In tomatoes, freezing darkens the leaf or stem tissues, causing them to wilt and turn brown. It can be hard to tell if the growing point is dead, but the damage may be more visible the day after the frost.
Chilling injury in tomato and pepper plants
Chilling can cause:
- stunted growth
- wilting
- surface pitting or necrosis of foliage
- increased susceptibility to disease
Tomato plants can suffer from chilling injuries when temperatures are between 0°C to 5°C.
Pepper plants can also suffer from chilling injury if temperatures stay between 0 to 10°C (32 to 50°F) for a long time. This injury may appear as puckered leaves and stunted growth.
The effects of temperature on tomato and pepper flowering
Extreme temperatures can negatively affect the flowering, pollination, and fruit production of tomatoes and peppers. Tables 1 and 2 show how different temperatures affect the flowering and fruit set.
Note: Temperature values refer to daily highs and lows in the field.
| Temperature | Effect on flowering, pollination, fruit set |
|---|---|
| Greater than 35°C (95°F) | Reduced fruit set |
| 18.5 to 26.5°C (65 to 80°F) | Optimum for fruit set |
| Less than 13°C (55°F) | Misshapen or catfaced fruit may result |
| Less than 10°C (50°F) | Poor fruit set |
| Temperature | Effect on flowering, pollination, fruit set |
|---|---|
| Greater than 32°C (90°F) day temperature | Pollen sterility occurs, flowers may drop |
| 16°C (61°F) | Optimum for flowering and fruit set |
| Less than 15.5°C (60°F) or greater than 24°C (75°F) night temperature | Poor fruit set |
Low temperatures experienced by the plant weeks before flower buds are visible can also affect flowering and fruit set.
A tomato plant which experiences temperatures below 15.5°C (60°F) for extended periods of time will begin to flower profusely. These flowers may remain open on the plant for several weeks, without forming fruit. Larger flowers and increased branching of clusters can also show up because of low temperatures weeks before flower buds are visible.
Chilling and freezing injury in tomato and pepper fruit
Low temperatures can damage the fruit of warm season crops like tomatoes and peppers.
Daytime temperatures of 15.5°C (60°F) with nighttime temperatures of 10°C (50°F), 4 to 5 weeks before a tomato flower cluster blooms, can lead to misshapen or catfaced fruit.
Nighttime temperatures of 7 to 10°C (45 to 50°F) during pepper flower development can cause the fruit to be smaller or misshapen.
Chilling injury in tomato and pepper fruit
Tomato fruit can get chilling injuries if exposed to temperatures of 10°C for more than 14 days, or 5°C for more than 6–8 days. Even if the fruit doesn't show obvious damage in the field, exposure to shorter periods of low temperatures can still lead to storage problems.
Pepper fruit can also be injured by prolonged temperatures below 8°C.
Freezing injury in tomato and pepper fruit
Frost injury is more severe than chilling injury.
Tomato and pepper fruit can become damaged when exposed to temperatures between 0 and -1°C.