Can I Leave Orchids Outdoors?

Growing Orchids Outdoors

• In tropical and subtropical regions, gardeners may grow orchids outdoors year round. The plants may be mounted on palm or tree trunks, hung in baskets or placed in heavy pots. When low temperatures approach 55 degrees in autumn, the orchids must be brought indoors to a protected porch or glasshouse. If orchids are normally grown as houseplants, they may be brought outdoors from spring to fall. Once spring nighttime temperatures no longer drop below 60 degrees, plants may be relocated outdoors to receive the benefit of higher humidity, rain showers and added warmth in summer.

Types

• Based on your climate and regions, native orchids already grow and prosper outdoors. It's the tropical orchid species such as those in the genera Oncidium, Cattleya, Dendrobium, Vanda, Phalaenopsis and the like that warrant concern regarding temperature when placed outdoors. In addition to appropriate warm temperatures, remaining ideally in the 60- to 90-degree range, the plants must receive the right amount of light. Some orchids suffer burned foliage if placed in too much direct sunlight, while other species falter if the light levels are too low.

Exceptions

• To prevent any cold damage, growth stunting or stress, bring your tropical orchid species and hybrids indoors each fall before it gets too chilly. Some orchids tolerate slightly colder fall temperatures and actually need exposure to some chilly temperatures to help produce flower spikes later in winter and early spring. Phalaenopsis orchids tolerate temps into the 40- to 50-degree range as long as conditions aren't wet. Cymbidium orchids produce flowers better when temps drop into the 30s and 40s.

Geographical Insight

• Leave orchids outdoors year round only in U.S. Department of Agriculture plant hardiness zones 10b and warmer. Hawaii, Puerto Rico, extreme southern California and South Florida remain warm enough in winter to allow the orchids to escape frosts. A lathe house or large patio offers additional protection from cold in these areas when winter weather does become chilly and wet. While orchids must acclimate to outdoor temperatures in the 40- to 50-degree range, they survive. The especially cold-tender orchids may still warrant placement in a heated glasshouse or sunroom over winter, especially if flowers and buds are present.