Does an Orchid Have to Be in Sunlight?

Orchids

Orchids, like all plants, require light to survive. This light can be either sunlight or artificial. Orchids must receive the correct intensity and amount of light; the exact amount depends on the type of orchid. There are many types of orchids, and they frequent a wide range of USDA Hardiness Zones (4 to 12). Some grow well in sun; others do best in shade. Most orchids sold are epiphytics (a plant which grows on or in a tree), and originate from the tropics.

Amount of Sunlight

The amount of sunlight that falls upon an orchid is very important for the plant's food production (photosynthesis) and triggering flower production. Depending on the type of orchid, 12 to 16 hours of light per day are needed for good growth; the summer months provide this. During the winter, sunlight is reduced, causing the orchid to go into a period of rest (unless it is adapted to low light, such as Phalaenopsis).

Intensity of Sunlight

The intensity or strength of light that an orchid needs varies from type to type. Some are exposed to full sun for most of the day, while others require the low-level light from the shade of a tree canopy. For easily available orchids such as Cymbidium, which grows in a temperate climate zone in the summer, position on an east-facing window sill, but, during winter months, acclimatize these orchids to a south-facing window.

Problems of Incorrect Light Levels and Intensity

Orchids are adapted to their natural conditions, which must be replicated

Exposing orchids to under 12 hours of sunlight a day, or to too much shade, will cause the production of darker-than-usual leaves, indicating poor food production and resulting in the orchid failing to flower again. If the orchid gets over 16 hours of light a day, it may stop flower production. If the sunlight is too strong, leaves will go pale, scorch and be irreparably damaged, which may lead to the death of the plant.

Sunlight Levels in Buildings

Place orchids in in direct sunlight.

Buildings are designed for people and not plants, so when an orchid is brought into one, it is important that its sunlight requirements are known. As a house plant, orchids are typically placed where they look nice -- usually in direct sunlight -- but this can scorch and even kill popular varieties such as Phalaenopsis, which needs the weak early-morning sun found on an east-facing sill and then shade for the rest of the day.

References

• Orchid Care Manual, Brian and Sarah Ritterhausen