Moving an orchid outdoors for the summer offers benefits like increased air circulation and higher humidity, but requires careful consideration. Orchids accustomed to stable, filtered indoor light would suffer shock if immediately placed in harsh outdoor conditions. The simple answer to putting an orchid outside in the sun is generally no, as most popular household orchids require bright, highly diffused light to thrive. Safely transitioning the plant outdoors demands a strategic approach that protects its leaves from immediate damage while slowly introducing stronger natural light.
Understanding Sun Damage
Exposing an orchid to direct, unfiltered sun, especially during midday, rapidly leads to sunburn. Orchid leaves have a light saturation point; exceeding this limit causes excess energy to convert into heat. This raises the internal leaf temperature to unsafe levels, causing the plant’s cells to die.
The initial signs of sunburn appear as bleached or yellowed spots on the foliage, typically where the sun strikes most directly. If exposure continues, these pale areas rapidly turn into distinct, dark brown or black scorch marks, creating a necrotic patch. Thin-leaved orchids, such as Oncidium varieties, are often more susceptible than thick-leaved counterparts. Sun damage can also affect roots in clear pots and cause flowers to discolor and drop prematurely.
Defining Ideal Light Conditions
Most common orchids require bright, indirect light to stimulate healthy growth and flowering, rather than direct sunlight. In their native habitats, many orchids are epiphytes, growing attached to trees where the forest canopy filters the sun’s rays. This is replicated by providing dappled shade outdoors, which offers intense brightness without the damaging direct intensity.
Ideal outdoor placement involves areas receiving filtered light, such as under a deciduous tree canopy or on a covered porch shielded from the afternoon sun. Morning sun is generally tolerated better than the harsh midday or afternoon rays. If a suitable natural location is unavailable, a shade cloth that blocks 50% to 70% of the light can be used to create the necessary filtered environment. Different orchid types have varying needs; for instance, Cattleya can tolerate more light than Phalaenopsis.
The Process of Moving Orchids Outdoors
Safely transitioning an orchid from a stable indoor environment to fluctuating outdoor conditions requires a gradual process called “hardening off.” This acclimation period allows the plant to develop a thicker protective cuticle, helping it withstand higher ultraviolet radiation and increased air movement. The process should take approximately one to two weeks to minimize shock.
Begin by placing the orchid in a deeply shaded, sheltered spot for only a few hours each day, bringing it back inside every night. Over seven to ten days, slowly increase the duration of its outdoor stay and gradually introduce it to brighter light, such as morning sun. Before the transition, inspect the orchid thoroughly for pests that might thrive outdoors. A minimum nighttime temperature threshold of 55°F to 60°F must be consistently met before the orchid is left outdoors overnight to prevent temperature shock.