To grow an orchid, you have to think like an orchid. The golden rule for orchid success is to duplicate the plant’s natural conditions as closely as possible. In nature, most orchids are epiphytes, meaning they grow on other objects, clinging to rough bark or even stone. The showy orchids favored by most people are usually either phalaenopsis hybrids or dendrobium hybrids.
About Orchids
The orchid family is one of the largest in the realm of flowering plants: More than 25,000 species grow naturally, on every continent except Antarctica. The greatest concentration of orchid varieties is found in the tropical regions of the world, namely in Asia and Central and South America. In most of North America, orchids must be grown indoors (exceptions include natives such as the lady’s slipper).
- Every orchid has a characteristic, highly evolved lip, a petal that protrudes in a blossom of three petals and three sepals, some fused together.
- Every orchid has evolved to attract a particular pollinator, which has led to orchids’ enormous variety in appearance.
- Orchids are either epiphytic or terrestrial most tropical orchids are epiphytic. In the wild, epiphytes cling to trees and stumps, drawing moisture from the mist and rain and decomposing leaves.
How to Grow Orchids
Orchids are usually grouped into two broad categories that characterize their growth habits. Monopodial orchids have a single, upright stem, with leaves arranged opposite each other along the stem. The flower stem appears from the base of the uppermost leaves. Orchids with this growth habit include the phalaenopsis and vandas.
The more common growth habit is sympodial. These orchids grow horizontally, sending out new shoots from the old rhizome. Leaves and flower scapes form at the top of the new shoots. Many sympodial orchids form pseudobulbs, which are swollen shoots that store water and nutrients to help the plant survive periods of prolonged drought. Sympodial orchids include cattleya, cymbidium, oncidium and dendrobium.
Orchids can also be classified by their native habitat, which gives an indication of the temperature, moisture and light levels they prefer. Orchids native to the humid tropics, such as phalaenopsis and paphiopedilum, prefer daytime temperatures of 73° to 85°F, with 80 to 90 percent humidity. They are happiest in an east or southeast window where the light is not too intense.
Warm-climate orchids, including cymbidiums and dendrobiums, are accustomed to an average temperature of 55° to 70°F, a steady supply of moisture, and good air circulation. They are generally happy in a south-facing window, though they may need a little shading during high summer.
Cattleyas and some oncidiums grow where days are dry and relatively cool. They are able to tolerate a long dry season with temperatures of 80° or 90°F, followed by a distinct rainy season. Their need for light is high, so they should be placed in a sunny, south-facing window.
High-altitude orchids, such as masdevallia and epidendrum, grow in the cloud forests where average temperatures are 60° to 70°F, and humidity is very high. These orchids prefer filtered light that is not too intense.
Repotting Orchids for Success
To re-pot your orchid, follow these steps:
Remove it from the plastic pot and carefully remove as much of the moss as you can. Healthy roots should be white and firm, with a small green growing point.
Cut away any shriveled, rotten or blackened roots.
Set the plant into the pot and fill in around it with potting mixture. The plant should be firmly situated, but it will not be completely anchored. Eventually, new roots will grow through the potting mixture and attach to the pot itself, thus anchoring your plant.
Once it’s re-potted, find a good spot. An east-facing window with a few hours of mild morning sun is perfect. To provide the necessary humidity and catch run-off water, put the plant into a wide, deep tray and fill the tray with gravel.
How to Care
Light:
As a general rule, orchids are light-hungry plants. For best results, they should get 12 to 14 hours of light each day, year-round. In a tropical environment, the duration and intensity of natural light does not vary as it does in temperate climates. For this reason, you may need to move your orchids around, and supplement with artificial light to keep them happy during the winter months.
South- and east-facing windows are usually the best spot for orchids. West windows can be too hot, and northern ones are usually too dark. If you don’t have a good window location for your orchids, they will be perfectly happy growing under artificial lights. Orchids should be positioned no more than 6 to 8 inches away from a set of 4-foot fluorescent bulbs. Opinions vary as to the benefits of cool white, warm white, and grow light bulbs. The new full-spectrum bulbs are probably the best all-around choice. Some orchids with very high light requirements, such as vandas and cymbidiums, may need high-intensity discharge lighting in order to flower.
Watering:
Most orchids can tolerate drought far better than they can tolerate excess moisture. Nothing kills an orchid faster than letting it sit in a water-logged pot. Without adequate air circulation, the plant will suffocate and die.
As a very general rule, orchids should be watered once a week. The growing medium should be allowed to dry out between waterings, and excess water should not come in contact with the roots or the growing medium. After being re-potted, most orchids will not resume active growth for several months. Water very sparingly during this readjustment period.
Humidity:
Most tropical orchids prefer humidity levels of 60 to 80 percent. With the winter-time humidity level in most homes hovering closer to 30 percent, orchid growers often use a humidifier, or set their orchids in special humidity trays or gravel-filled trays. Some orchids also benefit from being misted.
Fertilizer:
Orchid-growing mediums provide very few nutrients, so orchids must be fertilized to sustain healthy growth. Use a liquid fertilizer, and dilute it more than you would for other plants. Fertilizer should only be applied when plants are in active growth. This means that most orchids should not be fertilized in midwinter, or right after they have been re-potted. Many growers use a 30-10-10 fertilizer, though others prefer 10-10-10 or 10-10-30. Misting your orchids with fish emulsion or seaweed extracts will provide micronutrients.