Pepper plants generally do not survive hard frosts without protection. These warm-season vegetables are highly sensitive to cold temperatures, and even a light frost can cause significant damage to their foliage and fruit. The survival of a pepper plant through a frost event depends on the severity of the cold and the protective measures taken.
Understanding Frost Damage
Frost damages pepper plants by causing water within their cells to freeze. When temperatures drop below freezing, ice crystals form inside plant cells, expanding and rupturing cell walls. This cellular damage leads to dehydration and tissue death, appearing as blackened, wilted leaves and stems. Tender new growth, flowers, and developing fruits are particularly vulnerable.
A light frost occurs when air temperature drops slightly below freezing, often freezing dew on plant surfaces. This might only damage outermost leaves or tender tips. A hard frost involves temperatures well below freezing, sustained for several hours, causing widespread tissue death throughout the plant.
Pepper Plant Cold Tolerance
Pepper plants are warm-season crops that thrive in temperatures above 60°F (15°C). Temperatures below 50°F (10°C) can cause stress, slowing growth and reducing fruit production. Below 40°F (4°C), plants may experience minor damage, such as leaf yellowing or stunted development, even without freezing.
Temperatures at or below 32°F (0°C) are freezing and pose a significant threat. A brief exposure to light frost might injure foliage, making leaves appear water-soaked and black. A hard frost, with temperatures significantly below freezing for an extended period, will likely kill an unprotected plant. The severity of damage escalates with the duration and intensity of the cold.
Protecting Pepper Plants from Frost
Protecting pepper plants from frost involves insulating them from freezing temperatures. Covering plants before sunset is effective; materials like row covers, old blankets, tarps, or inverted buckets can trap ground heat. Remove covers after sunrise to prevent overheating and allow sunlight exposure.
Watering the soil thoroughly before a frost also provides protection. Moist soil retains heat more effectively than dry soil, radiating warmth and keeping the surrounding air slightly warmer. For container-grown pepper plants, move them indoors or to a sheltered location like a garage or under an overhang. Mulching around the base offers some soil insulation, though it is less effective for aerial parts.
Caring for Frost-Damaged Plants
After a frost, wait a few days before assessing the full extent of damage. Some damage may not be immediately apparent; waiting allows for a clearer distinction between healthy and compromised tissue. Once visible, carefully prune away any dead, blackened, or mushy parts. Cut back to healthy, green stem tissue, if any remains.
If the main stem feels frozen solid, or damage extends to the crown, the plant is likely unrecoverable. If healthy stem or root material persists, good care can encourage recovery. Ensure the plant receives appropriate watering without over-saturating the soil, and avoid immediate fertilization as it needs to focus energy on healing.
Harvesting Peppers Before Frost
Harvesting all mature and nearly mature peppers before a predicted frost salvages your yield. Even if green, they can be picked and ripened indoors. This ensures a final harvest, and this proactive measure maximizes the return from your pepper plants.