Choosing Plants and Pots
When choosing an orchid, select one that enjoys conditions that you can provide at home, such as a moth orchid (Phalaenopsis) or a boat orchid (Cymbidium). If you can keep your plants in a heated greenhouse, your choice is wider. Hybrids of the following orchids are generally reliable, given the right conditions: Cattleya, Dendrobium, Epidendrum, Oncidium, and the slipper orchid Paphiopedilum.
Before buying an orchid, look over the plant for any signs of pests and diseases, and make sure it has plenty of flowers and firm buds. Check that the aerial roots are firm and pale with green tips, and that any roots visible through a clear plastic pot (in which orchids are often grown) are equally healthy, and not black. Most tropical orchids have aerial roots that absorb water and photosynthesize like leaves, taking energy from the sun and converting it into food. As a result, they can survive in very little soil, and require only small containers. Some should be grown in transparent pots to enable the roots to absorb sunlight.
Buy your orchids from a reputable source, such as a specialist nursery. Avoid those that have been sitting around in a drafty store for weeks, because they may not survive for very long.
Watering and Feeding
The most common cause of an orchid's early demise is over-watering. Although different orchids have different needs, most require watering once or twice a week in spring and summer, and once every two weeks in winter. In the case of Cattleya, water just enough to prevent the pseudobulb (the swelling at the base of the stems) from shriveling. Keep Dendrobium almost dry in winter. Use a can filled with rain- or filtered water at room temperature, and pour it into the pot until it runs from the base. For plants with congested roots, submerge the pot to just below the rim in a bowl of water, and leave until the soil surface is damp, then remove and allow to drain. Also provide some humidity by misting the leaves with rain- or filtered water, avoiding the flowers; or sit the pots on a tray of damp pebbles or gravel.
Orchid soil contains no nutrients, so start feeding your plants with an orchid fertilizer as soon as you get them home, following the instructions on the package. Some, such as Phalaenopsis, should be fed weekly, while others need less frequent applications.
Wipe Away Excess Moisture
After watering your plants, leave them to drain and wipe off any excess moisture on or between the leaves with a soft cloth to prevent rotting.
Avoid Cold Showers
Don't mist orchids with cold water; leave rain- or filtered water to warm up to room temperature, and spray in the morning.
Positioning Your Orchids
As with watering, the light requirements of orchids differ depending on the type. Epidendrums grow on tropical tree branches in the wild and like bright, indirect light. Cymbidium hybrids also prefer bright light, and should be set outside in a sheltered spot during the summer, then given a bright, cool position indoors out of direct sun, such as a conservatory or a frost-free porch, in autumn and winter. Cattleya and Oncidium prefer a bright position that offers some shade at midday, such as an east- or west-facing windowsill, but move them to a bright spot that receives sun all day in winter when light levels are significantly lower. If you don't have a light area in which to keep an orchid, choose a Phalaenopsis or Paphiopedilum hybrid. These dislike strong sunlight, preferring a shady site from late spring to autumn.
The large exotic blooms of the moth orchid belie its easy-going nature. It requires soft light and is quite happy in a warm room.
Position a Dendrobium where it will receive bright filtered light and keep humidity levels high in the growing season. It will then reward you with these exquisite flowers.
Before buying, make sure you can give your chosen orchid the temperature it needs. Remember that most require a 10 degrees F drop between day and night.
Tender orchids, such as Dendrobium hybrids and Phalaenopsis, require warmth all year, with a minimum winter temperature of 61-64 degrees F. They will tolerate occasional dips, and are fine in centrally heated houses, if moved away from cold windowsills at night.
Cattleya, Epidendrum, and Paphiopedilum require more warmth in winter than cool-growing orchids, but will tolerate slightly higher temperatures in summer. Most grow well indoors, but should be moved away from cold windowsills at night during winter.
This group includes Cymbidium and Oncidium, which prefer low temperatures all year. Stand them outside in summer in a sheltered spot in cool climates, then bring them in to an unheated room, such as a cool conservatory or greenhouse, for winter, keeping them at around 46-50 degrees F.
With its spidery green and maroon flowers, the cold-growing orchid (Cymbidium kanran) is a fantastic orchid for those with a cool room to keep it in throughout winter.