Calathea, often known as the peacock plant or part of the broader prayer plant family, is prized for its striking, decorative foliage. These popular houseplants bring a tropical aesthetic indoors with their vibrant patterns and unique leaf movements. While Calatheas thrive in stable indoor conditions, they can be grown outside if specific, carefully managed conditions are met. Outdoor viability depends almost entirely on the local climate and the ability to maintain a consistent microclimate around the plant.
Temperature Limits and Hardiness Zones
The primary constraint for growing Calathea outside is its sensitivity to cold temperatures, stemming from its tropical South American origins. These plants flourish in warm, consistent temperatures, ideally ranging between 65°F and 85°F (18°C and 30°C). The plant begins to show signs of stress, such as leaf curling and browning edges, when temperatures dip below 60°F (15°C).
Temperatures falling below 55°F (13°C) for sustained periods will likely cause cold damage, which can be irreversible and fatal to the plant’s root system. For this reason, Calatheas are only capable of year-round survival when planted directly in the ground in USDA Hardiness Zones 11 and 12, which are characterized by frost-free winters.
For growers in all other geographical locations, outdoor growth must be seasonal, a practice often referred to as “summering.” This involves keeping the Calathea in a container and moving it outside only after all danger of frost has passed and night temperatures consistently remain above 60°F (15°C). The plant’s inability to survive even a light frost makes careful monitoring of the forecast imperative for its survival during transitional seasons.
Optimizing Light and Moisture Outdoors
Once minimum temperature requirements are met, the next challenge involves managing light intensity and ambient moisture levels outdoors. Calatheas naturally grow on the rainforest floor, protected by a dense canopy, meaning they are adapted to low light conditions. Direct, unfiltered sunlight, particularly the intense afternoon sun, will quickly scorch and fade the delicate foliage.
The ideal outdoor placement is in a location that receives bright, indirect, or dappled shade throughout the day, such as beneath a patio cover or a large, leafy tree. An east-facing spot that receives only gentle morning sun, or a north-facing area that is fully shaded, typically works best. Filtered light is necessary, as the plant’s colorful leaf patterns will fade in overly bright conditions.
High ambient humidity is just as important as controlled light, and this is often the most difficult factor to replicate outdoors. Outdoors, greater air movement increases the rate of transpiration and moisture loss from the leaves. Calatheas prefer humidity levels above 60%, and low moisture will result in the browning or crisping of leaf margins.
To counteract this, placement near a water feature or grouping the Calathea closely with other plants can help create a localized, more humid microclimate. Watering strategy must also change; outdoor containers dry out much faster due to increased air circulation and warmth. The soil should be kept consistently moist but never saturated, which often means checking the top inch of soil daily during the hottest months.
Safe Seasonal Transition and Acclimation
For growers who practice “summering” their Calatheas, the transition between indoor and outdoor environments requires a period of gradual adjustment known as “hardening off.” This process allows the plant’s tissues to adapt to the higher light intensity, increased air movement, and temperature fluctuations of the outdoors. Hardening off should take between one to two weeks to prevent severe shock.
Begin by placing the potted plant in a fully shaded, sheltered area for only a few hours a day, ideally during the morning or late afternoon. Over the course of the week, incrementally increase the amount of time the plant spends outside, slowly introducing it to slightly brighter (but still indirect) light and longer periods of exposure. Skipping this step can lead to immediate sun-scald and leaf drop.
Before the Calathea is brought back inside for the winter, careful inspection is necessary to prevent the introduction of outdoor pests into the home environment. Spider mites are a common issue, especially when plants are exposed to lower humidity or higher temperatures outdoors. The plant should be moved back indoors well before nighttime temperatures consistently drop below the 60°F (15°C) threshold, typically in early autumn.