Pothos, scientifically known as Epipremnum aureum, is a popular and generally forgiving houseplant known for its cascading vines. While often touted as resilient, its tropical origin makes it sensitive to temperature extremes, especially cold exposure. A sudden drop in temperature can quickly lead to severe physical damage. Understanding its limits is the first step in ensuring its long-term health.
Pothos Cold Tolerance Thresholds
Pothos plants thrive in warm, stable conditions, mirroring their native jungle environment. The optimal temperature range for robust growth is consistently between 65°F and 80°F (18°C and 27°C). Within this range, the plant’s metabolic functions, like photosynthesis and nutrient uptake, operate efficiently.
The threshold for physiological damage, known as chilling injury, begins when temperatures drop below 50°F (10°C). Exposure at this level slows down enzymatic activity, which can impair growth. Severe harm occurs when the temperature approaches or falls below freezing, 32°F (0°C). At freezing temperatures, water inside the plant’s cells expands into ice crystals, rupturing the cell walls and causing immediate tissue death. The extent of the damage is a factor of both the low temperature reached and the duration of the exposure.
Recognizing Cold Damage
Cold stress manifests with distinct visual and tactile symptoms that allow for accurate diagnosis. Within 24 to 48 hours of exposure to damaging temperatures, the foliage will often begin to show signs of cellular collapse. Leaves and stems will turn a dark brown or black color, and the tissue will feel mushy and water-soaked to the touch.
This rapid, necrotic discoloration is a key differentiator from other common plant issues. Overwatering causes leaves to become soft and limp, but the discoloration usually presents as yellowing, often starting at the edges, and is accompanied by perpetually soggy soil. Conversely, cold damage is characterized by a quick, black, and often slimy breakdown of the tissue due to the physical destruction of the cells. Pest infestations, such as spider mites, present with physical signs like webbing or stippling on the leaves, which is entirely unrelated to the uniform tissue death caused by cold.
Cold-damaged leaves often droop and wilt, but they retain a soft texture, unlike underwatered leaves which are dry and crispy. The damage typically appears on the parts most exposed to the cold, such as foliage near a window or the tips of the longest vines. Identifying this specific pattern of black, mushy decay is crucial for moving quickly toward a recovery plan.
Immediate Action and Recovery Steps
The most important immediate action is to relocate the pothos to a warm, stable environment without delay. The ideal recovery temperature is a moderate room temperature, ideally between 65°F and 75°F (18°C and 24°C). It is important to avoid placing the plant directly next to a heat source, such as a radiator or a heat vent, as a sudden change in temperature can cause further shock to the already compromised tissues.
The plant must be given time to stabilize before any significant pruning takes place. Wait a few days to a week for the full extent of the damage to become apparent, as the plant will naturally cordon off the dead areas. Once the dead tissue is clearly defined, use sharp scissors or pruning shears to remove all blackened or mushy leaves and stems. Sterilizing the cutting tool with rubbing alcohol before and after use is necessary to prevent the introduction of fungal or bacterial pathogens into the fresh wound sites.
Recovery requires a significant adjustment to the plant’s watering schedule. Since the pothos has lost a portion of its foliage, it will be transpiring and photosynthesizing less water than before. Excess moisture in the soil will lead to root rot, which is a secondary consequence of cold damage. Allow the top two inches of soil to dry out completely before watering lightly, and temporarily withhold all fertilizer, as the plant needs to conserve energy for healing rather than new growth. Full recovery is a slow process that can take weeks or even months, requiring patience while waiting for new growth to emerge from the surviving nodes.
Strategies for Future Protection
Preventing future cold damage involves careful placement and seasonal awareness, focusing on eliminating sources of cold stress. Pothos should be positioned a few feet away from uninsulated window panes, especially during winter nights when glass surfaces radiate cold air. The space between the plant and the glass creates a microclimate that can easily dip below the 50°F damage threshold.
Similarly, plants must be kept away from exterior doors that open frequently or from air conditioning vents that blow cold air directly onto the foliage. Placing a pothos in a corner or grouping it with other houseplants can help create a slightly more humid and insulated environment. During the winter, the use of sheer curtains can provide a minimal buffer against the cold radiating off the glass without blocking too much necessary light.
Safe transportation is another key preventative measure, especially when moving the plant from a store to a home in cold weather. Even a short walk from a car to a house can cause cold shock if the temperature is near freezing. The plant should be wrapped completely in insulating materials like paper or a double layer of plastic to trap warm air and block cold drafts. Ensuring the vehicle is warmed up before the plant is placed inside and keeping the foliage away from the vehicle windows will protect the leaves from contact burn caused by the cold glass.