ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Thursday, January 18, 1996 TAG: 9601180036
SECTION: CURRENT PAGE: NRV-4 EDITION: NEW RIVER VALLEY
COLUMN: Hoein' & Growin
SOURCE: SHEILA WINETT
It's winter - cold, snowy, windy. What better way to take your mind off the current weather than to think about things exotic and tropical - orchids?
Despite their reputation as finicky hothouse specimens, the American Orchid Society says that these beautiful flowering plants are hardy and adaptable.
There are at least 20,000 species of orchids and more than 100,000 hybrids.
Some very hard-to-please varieties exist, but there are at least as many strong, easy-to-grow orchids that can adapt to the temperature and light in most homes.
These tropical beauties can be coaxed into bloom. The reward is beautiful flowers when they are needed most, from December to April.
Orchids do not grow in soil. They attach their thick roots to the sides of trees, cling to bark and absorb water and nutrients from the air, rain and whatever drips from the tree.
A no-soil environment can be simulated by growing orchids in pots filled with bark chips, pebbles or some other loosely packed material.
The growing medium must provide roots with plenty of air and allow water to drain quickly. A waterlogged pot will prevent orchid roots from getting oxygen: They will suffocate and rot and the plant will die in a hurry.
In nature, most orchids experience big temperature differences each day. Unlike many houseplants that suffer from temperature fluctuations, orchids will fit the cold-weather heating pattern found in most homes - thermostats turned up during the day and down at night. A 10-degree drop in temperature each night during fall and winter will help induce orchids to set flower buds.
Sufficient light is a chief concern for would-be home orchid growers. Orchids are classified into groups according to their light requirements. The high-light group requires about 3,000 foot-candles. Those that need 2,000 to 3,000 foot-candles are in the medium-light group. A minimum of 1,000 foot-candles is needed by plants in the low-light category. Lack of light won't kill orchids, but it will inhibit flowering.
Leaves reveal whether plants are getting enough light.
When a houseplant has deeply colored, green foliage, it is a sign of the plant's health. Orchids are just the opposite: If they are getting enough light, the plant will have pale to medium green leaves with a touch of yellow. Dark green leaves signal a lack of sufficient light.
Here is a simple test to judge whether your orchids are getting enough light: Place your hand about six inches above the leaves and look at the shadows that are cast. A sharp-edged shadow means high light, a soft shadow means medium to low light, and no shadow means there's not enough light to allow your orchids to flower. Light can be manipulated through artificial lighting and other means.
Orchids do not need heavy fertilization. A weekly dose of 20-20-20 fertilizer diluted to about one-quarter of the strength recommended on the package will do.
Once a month, water thoroughly with plain water to wash away the accumulated fertilizer salts. In autumn, switch to a high-phosphorus low-nitrogen formulation (10-30-20) to encourage flower production.
Lack of adequate humidity in most homes is a key reason that home growers have difficulty with orchids. Fifty percent humidity or higher is necessary. Most homes are far more arid
Raise the humidity level in the immediate vicinity of your plants by using a humidifier, misting, grouping plants, placing your plants in pebble trays filled with water, or tenting plants in plastic. With tenting, provide ventilation to discourage bacterial or fungal growth.
The American Orchid Society has local chapters throughout the country. The Blue Ridge Orchid Society meets every second Sunday of the month (except July-August) at the Roanoke Council of Garden Clubs building on Avenham Avenue in Roanoke.
New River Valley residents may call Stephen Sheckler at 951-0172 or 231-6653, or e-mail at stephenvt.edu. Dee and Jim Gresham, BROS secretaries, can be reached by mail at Route 4, Box 294E, Lynchburg, Va. 24503, or by phone at (804) 384-6577. Their e-mail address is jgreshamena-east.ericsson.se.
BROS sponsors an annual orchid show at Valley View Mall in Roanoke the weekend before Mother's Day. Beginners can see lots of plants, acquire some plants or growing supplies, and get advice on how to grow them. The Wide World Web's AOS home page includes many beautiful photographs to whet your appetite and links to many resources. The address is http://gnn.com/wic/wics/garden.19.html. Write the AOS at 6000 S. Olive Ave., West Palm Beach, Fla. 33405 or call (407) 585 8666. A membership costs $30 per year.
Sheila Winett is a master gardener.
LENGTH: Medium: 87 linesby CNB