Caring for orchids:

The enormous diversity of the orchid family precludes any single recipe for care. The basic care information presented here covers cultivation for some common genera that are available commercially.

Light
Orchids need sufficient light to thrive and bloom. Light levels for some commonly grown genera:
• full sun: Vanda, some Epidendrum
• bright light with some direct sun: Cattleya, Dendrobium, Oncidium
• shade with little or no direct sun: Masdevallia, Paphiopedilum, Phalaenopsis
Some orchids can be grown under artificial light, but others demand natural light.

Water
Water needs vary tremendously among different species. Variations in temperature, light, and humidity must be factored in as well. Epiphytic orchids require excellent drainage, and their roots will quickly rot if they are kept too wet or left sitting in water. On the other hand, some terrestrial orchids, such as Sobralias, enjoy very moist soil during summer.
• daily water: Masdevallia, Odontoglossum, Vanda
• water several times a week: Dendrobium, Epidendrum, Paphiopedilum, Phalaenopsis
• water weekly: Cattleya, Laelia

Humidity
Orchids enjoy high humidity around their leaves, roots, and flowers. Ideal humidity levels range from 50%-75%. Low humidity levels can cause flowers to quickly wilt, invite pests, and can eventually kill the plant.

Temperature
Temperature needs vary according to species. While many tropical orchids come from hot, steamy jungles, many other species live high on the cool slopes of the Andes, Himalayas, or other mountain ranges. At elevation, they live in cloud forests with constant fog and rain.

Orchids are usually grouped into 3 temperature ranges:
• Warm growers need warm days with nighttime minimums of 60°-65°F (16°-18°C.) Examples include Cattleya, Phalaenopsis, and Tolumnia.
• Intermediate growers need mild days with nighttime minimums of 50°-55°F (10-13°C.) Examples include Epidendrum, Oncidium, and Phaius.
• Cool growers need cool days with nighttime minimums of 40°F (4°C), although some can handle light freezes. Examples include Masdevallia, Odontoglossum, and many Pleurothallis.
All orchids require slightly cooler nighttime temperatures.

Fertilizer
Orchids grown in cultivation can derive some nutrients from the breakdown of their potting material (usually moss or bark.) Growers often add specialized orchid food, which includes nitrogen, potassium, phosphorus, and other nutrients.

Air Movement
All orchids require good air movement. Still air encourages damaging microorganisms and insect pests. Epiphytic orchids especially need good air movement around their roots.

Dormancy
Many orchids experience a dry season in their native environments. This includes all orchids with pseudobulbs. In cultivation, these plants typically go dormant in the winter. Water and fertilizer should be reduced at this time.

Repotting
When grown in pots, orchids usually need to be repotted every 2 or 3 years. Potting media decomposes over time, blocking critical air circulation around roots. At the start of the growing season (usually in spring,) growers:
• remove the plant from its pot, and discard the old potting material,
• clean the orchid’s roots, and remove any dead or damaged ones,
• reuse the flowerpot, or find a new, clean one based on the size of the remaining root-ball,
• replace the orchid in the pot with new potting material,
• allow the plant for recover for a few weeks in shadier conditions.