Pepper plants, warm-season crops, are sensitive to cold temperatures due to their tropical origins. Even brief exposure to chilly weather can significantly impact their health and productivity.
Key Temperature Thresholds for Pepper Plants
Pepper plants grow best when temperatures are between 65°F and 80°F (18-27°C). Bell peppers prefer 70-80°F (21-27°C), while hot peppers prefer 70-85°F (21-29°C). Nighttime temperatures between 60-70°F (15-21°C) are beneficial for fruit development.
Temperatures below 50°F (10°C) cause stress, slowing growth. At 40-50°F (4-10°C), plants may stop growing and wilt. The critical temperature is 32°F (0°C); freezing temperatures will cause damage or death. Cold stress occurs when temperatures are too low for metabolism, while freeze-frost stress involves ice crystal formation and cellular damage.
Identifying Cold Damage in Pepper Plants
Cold damage on pepper plants shows several visible symptoms, appearing hours or days after exposure.
Leaves often show wilting, discoloration, browning, or blackening, starting as scorched edges. Stems might soften or turn black, indicating severe damage. Growth can become stunted, and foliage may appear puckered. For fruit, cold exposure can lead to soft spots, stunted development, or premature dropping. Discoloration at the main stem’s base indicates extensive damage.
Protecting Pepper Plants from Cold
When cold temperatures are expected, protect pepper plants. Covering plants with frost cloths, blankets, or sheets traps warmth, insulating them from cold and frost. For container-grown peppers, move them indoors to a garage, shed, or covered patio.
Watering plants thoroughly before a cold snap helps, as moist soil retains heat better. Cloches or row covers create a mini-greenhouse effect, protecting smaller plants. Applying mulch around the base insulates the soil and roots from temperature fluctuations.
Recovering Cold-Stressed Pepper Plants
If pepper plants have been exposed to cold, avoid immediate pruning. Dead foliage can offer insulation, and the full extent of damage might not be apparent. Wait until the weather warms and new growth emerges before deciding which parts to remove.
When pruning, remove only clearly dead or severely damaged parts, like mushy or black tissues, without over-pruning. Provide supportive care with adequate moisture, avoiding overwatering. Do not apply fertilizer immediately; allow the plant to recover naturally. Fertilize only once frost danger has passed and healthy new growth is established.