The peace lily (Spathiphyllum) is a popular houseplant known for its glossy foliage and white spathes. While it can be placed outdoors during the warmer months, the transition requires extreme care. Outdoor success depends entirely on providing a specific microclimate that avoids the harsh extremes of the summer environment.
Essential Outdoor Requirements
The primary danger outdoors is direct sunlight, which causes immediate leaf scorch. Because the plant naturally grows on the forest floor, it requires deep, consistent shade or highly dappled light, such as under a dense tree canopy or a covered porch. Even brief exposure to midday sun can result in brown spots and leaf burn, as the foliage is not adapted to intense ultraviolet rays.
Temperature control is equally important for this tropical species, which lacks cold tolerance. Nighttime temperatures must consistently remain above 60°F (15.5°C) before the plant can safely reside outside. Chilling injury can occur when temperatures drop below 55°F (13°C), and growth stalls below 60°F. Monitor weather forecasts and be prepared to bring the plant indoors immediately if an unexpected cold snap or heavy storm is predicted.
The Acclimation Process
Moving a peace lily directly from indoors to the outdoors will cause significant shock and leaf damage. This process, known as hardening off, must be performed over one to two weeks to allow the plant’s cells to adjust to increased light and air movement. Begin by placing the plant in its eventual shaded location for just one to two hours on the first day.
Each subsequent day, the amount of time outdoors should be incrementally increased, gradually exposing the plant to the elements for longer periods. If the plant shows visible signs of stress, such as wilting, drooping, or sudden yellowing of the leaves, the transition is moving too quickly. This slow, deliberate process is the only way to build the plant’s tolerance and prevent severe damage to the foliage.
Summer Care and Monitoring
Once fully acclimated, the peace lily’s maintenance needs change dramatically from its indoor routine. Increased heat, airflow, and evaporation outdoors mean the plant requires significantly more frequent watering. Check the soil daily, watering thoroughly when the top inch feels dry, which may be several times a week during hot weather.
The container must have excellent drainage, as outdoor container plants are susceptible to root rot if waterlogged by heavy summer rains. The outdoor environment also exposes the plant to new pests, including slugs, snails, aphids, and spider mites. Daily visual inspections of the leaves and stems are required, and minor infestations can often be managed by hosing the foliage off or manually removing the pests. Due to active summer growth, a slightly increased feeding schedule with a balanced, diluted fertilizer can be beneficial.
Preparing for the Return Indoors
The outdoor stay must end well before the first predicted frost, ideally when nighttime temperatures begin to drop consistently below 55°F (13°C). Before moving the plant back inside, a thorough inspection for hitchhiking pests is necessary. Every part of the plant, including the undersides of the leaves, the stems, and the surface of the soil, must be closely examined.
Hose down the foliage to dislodge any unseen insects and consider treating the soil with systemic granules or an insecticidal soap to eliminate pest eggs or larvae. After cleaning, place the peace lily in a separate, isolated location for one to two weeks, away from all other houseplants. This quarantine period ensures any remaining pests do not spread to your indoor collection.