How Much Sun Should Orchids Get?

Sunlight Needs

• In their native habitat, with ideal temperature, humidity, moisture and soil conditions, orchids often grow with substantial exposure to sunlight. However, growing many species and hybrids of orchids makes providing the correct light levels more challenging, but not impossible. Some orchid houseplants need or tolerate up to six hours of direct sunlight daily, including Vanda, Cattleya, Oncidium and Cymbidium. Many others are best when only receiving one or two hours at sunrise and then bright, indirect light the rest of the day. Some orchids, such as Paphiopedilum, should never be exposed to sun rays. Outdoors, wild orchids from the temperate zone typically do best with no more than six hours of sunlight, with shade from the hottest sun in the mid-afternoon. In the mountains or Arctic, cooler temperatures may require the native orchids to bask in all-day sun to escape freezing.

Safe Bets

• When you acquire a new orchid and you are unfamiliar with or cannot find any recommendations for how much light it should get, err on the side of caution. The safest lighting condition for an orchid would be very bright indirect light, such as just behind a translucent sheer curtain or under the milky, translucent panes of a greenhouse or sun room. You may always relocate the orchid later if you notice any damage from light or a failure to grow or produce a flower.

Sunlight Damage

• Orchids grown at a plant nursery are given optimal light and growing conditions so plants are robust and already in bloom, and have lush green foliage. Moving the orchid inside your home or office --- where light levels are dimmer, the humidity is lower and heating and air conditioning drafts are abundant --- can cause exposure to sun rays in a window to quickly result in scalding or holes. Too much light intensity scalds orchid leaves by creating brown edges or a brownish-bronze skin atop the green. In severe cases, a brown spot occurs where tissues fully die, and then the leaves overall display a sickly yellow hue. A light green to mildly yellow-green leaf color on orchids is all right; it's better to provide slightly higher light levels than not enough light. Indirect light is always safer than longer exposure to direct rays.

Seasonal Variation

• In the winter, when the sunlight angle is lower and less intense, orchids benefit from receiving some direct sun rays, especially from sunrise to mid-morning and again from mid-afternoon to sunset. Some sunlight in the winter provides enough energy for efficient and ample photosynthesis. From the spring to the fall, more shade is needed to prevent leaf damage, and to lower the temperature of plant tissues. Hotter air temperatures, lower humidity and stronger sun rays from March to September increase the need for watering and more shading.