Pineapple plants, scientifically known as Ananas comosus, are celebrated for their distinctive, sweet fruit. Originating from tropical and subtropical regions of the Americas, these plants are accustomed to consistently warm environments. This inherent tropical nature makes them particularly sensitive to cold temperatures, a significant challenge for growers outside their native climate zones.
Understanding Pineapple’s Cold Susceptibility
Pineapple plants thrive in temperatures ranging between 68 and 85 degrees Fahrenheit (20-30°C). Their growth significantly slows when temperatures drop below 60°F (15°C). Prolonged exposure to temperatures under this threshold can lead to plant stress and damage.
Even temperatures above freezing can harm pineapples through a phenomenon called chilling injury. Chilling injury occurs when plants are exposed to low, non-freezing temperatures, typically between 32-68°F (0-20°C). Chilling injury involves cellular damage. If temperatures drop to freezing, at or below 32°F (0°C), the water within the plant’s tissues can freeze and expand, causing physical damage to cells and potentially leading to the plant’s death. Almost all pineapple varieties are injured after exposure to 39°F (4°C) for 24 hours.
Recognizing Cold Damage
Identifying cold damage in pineapple plants involves observing several visual and physical cues. One of the earliest indicators is a change in leaf color, often appearing as browning or blackening, particularly at the tips or edges. The leaves may also develop red or white burn spots.
Beyond discoloration, affected leaves can become soft and mushy. Wilting or drooping of the foliage is another common sign. In severe cases, the entire plant may become mushy and turn black. Additionally, cold stress can lead to stunted growth or a complete halt in development.
Protecting Pineapples from Cold
Protecting pineapple plants from cold temperatures requires proactive measures, especially when forecasts predict a significant drop. For potted pineapple plants, the most effective strategy is to bring them indoors when outdoor temperatures begin to consistently dip below 59°F (15°C). Indoors, maintain a stable temperature between 65-75°F (18-24°C) and provide bright, indirect light for about six hours daily.
For in-ground pineapple plants, several methods can help mitigate cold exposure. Thoroughly watering plants before freezing temperatures arrive helps protect tissues and roots from frost damage. Applying a layer of organic mulch, such as wood chips, 2 to 4 inches deep and 12 to 24 inches in all directions around the plant base, can help retain soil moisture and heat.
Temporary shelters, like covers made from frost blankets, sheets, or plastic sheeting supported by stakes, can create a warmer microclimate around the plant. These covers should extend to the ground and be secured to prevent wind from dislodging them. For added warmth, large-bulb holiday lights or a 100-watt light bulb placed near the plant’s base under the cover can provide supplemental heat.