Guidelines for the beginner orchid hobbyist
Most cultivated orchids are perennial tropical plants. They require light, water, fertilizer and a humid atmosphere to grow well. Orchids with thick, fleshy roots can be potted in coarse bark chips, grown mounted on a piece of cork bark or on a branch. Orchids with fine roots are grown in a blend of small bark chips, sometimes with sphagnum moss, perlite or charcoal added to the mix. When buying an orchid, always ask what kind of potting mix is recommended for it.
At the Root of the Matter
Orchid roots need both moisture and air: roots need to breathe between waterings or risk decay. Dead orchid roots cannot absorb water or nutrients! Examine the potting medium and the roots of any orchid that fails to thrive – the plant may need repotting.
Orchids should be repotted:
- Every one to two years
- When the plant outgrows the container
- When the potting mix decays, becomes compacted or water-logged.
Light, Watering and Cooling
Many orchids have succulent or leathery leaves and swollen stems used to conserve water. Orchids with water storage capabilities generally require less frequent watering than those with thin leaves and no swollen stems. Orchids grow well in filtered sunlight or in artificial light. While most seedling orchids do well in moderate light, adult plants vary considerably in their light requirements and tolerance. Too much sunlight can burn leaves especially if the plants are not accustomed to it. Especially harmful is the heat produced by direct sunlight or by a plant touching a light bulb. Placing a sheer or lace curtain between the orchids and the sun is sometimes sufficient protection, especially for sun-tolerant plants but all orchids will benefit from air movement generated by a nearby fan. Fans can help cool plants especially if the leaves are first misted with water. As the water evaporates into the air stream, the leaf surface cools. Evaporative cooling can produce a 5°C drop in leaf temperature. Orchids grow best when the temperature varies at least by 5°C from the daytime high to the nighttime low.
Orchids have set points at which they grow best. It is up to the grower to discover the best temperature for each plant in their collection. For example, Cool-growing orchids such as Masdevallia
and Odontoglossum will have a set point around 10-15°C (50-59°F), while orchids termed Intermediate e.g. Cattleya and certain Oncidiums will have a set point around 15-20°C (59-68°F) and those referred to as Warm growers e.g. Phalaenopsis and Vanda will have a set point from 18-25°C (65-77°F). To make the road to discovery an easy one, the beginner is advised to start with orchids preferring one temperature range.
Flowering
Most mature orchids bloom once a year but their flowers frequently last a month or longer. Species orchid flowers are predictable as to size, colour, fragrance and blooming season. Hybrids are not as predictable but once a hybrid orchid has flowered, you can predict when it is likely to bloom again. If you have a particular preference for blooming season, ask a society member or vendor for recommendations.
Flowering pot-plants require sufficient light, regular fertilizer applications and watering to bloom well. Orchids are no exception. The challenge of growing orchids well and having magnificent blooms lies in finding the balance of light, temperature, water and plant food that is best for a particular plant.
Fertilizing Orchids
Although jungle orchids seem to survive, even prosper, clinging to the bark of a tree, they do benefit from a sprawling root system, employing it to harvest mineral nutrients derived from animal and plant debris in the forest canopy. Additionally, wild orchid roots frequently harbor mycorrhizal fungi that spread out through the tree bark, thus vastly increasing the harvesting area of the roots to absorb scarce minerals such as phosphorus.
Regular applications of dilute commercial fertilizer such as 7-7-7 can do wonders for a potted orchid plant. Always prepare solutions according to manufacturer’s instructions. There are products recommended both for growth and for flower production. Apply liquid fertilizer weekly after thoroughly watering a plant. Do not fertilize dormant plants, those with dead roots, or those not in active growth. Production of new leaves and roots is a sign of active growth. If new shoots become soft and floppy, fertilizer application may be too strong, too frequent or light may be inadequate to support growth.
Copyright © Canadian Orchid Congress 1993 This publication may be copied for free distribution only