Horticulture

Orchids as Houseplants

For those of you ready for something different, try growing orchids as houseplants. Orchids can be grown by anyone able to grow African violets. Orchids are fascinating because of their extraordinary variety of sizes, colors, shapes, and habits, as well as their variety of fragrances. There are some 30,000 species and even more hybrids.

Since orchids originate in all tropical parts of the world (and some temperate parts) their requirements vary considerably. Selecting varieties suitable for the growing conditions in your house improves your chances of success. Phalaenopsis (moth orchids) and some Paphiopedilum varieties (slipper orchids) are especially suited for successful home growing. Flowers on these two types of orchids are very long lasting with Phalaenopsis flowers lasting anywhere from two to six months.

Like any other houseplant, orchids require proper water, fertilizer, light, temperatures, and humidity. Plants should be grown in an east, south, or west window, but should be protected from direct midday sun. When growing orchids under artificial lights, it is important to provide light only as long as the natural day length. Extending day length may prevent blooming.

Orchids are classified by the temperatures they prefer. Warm- growing orchids, like Phalaenopsis, Doritis, and some Paphiopedilum and Dendrobium, grow best in temperatures between 65-80 degrees (F). Cool-growing orchids, like Cymbidium, Odontoglossum, Miltonias, and some Paphiopedilum and Dendrobium, prefer temperatures between 55-70 degrees. Most of the remaining varieties require intermediate temperatures of 60-75 degrees.

Humidity is very important to orchid plants. A relative humidity level of 40-80% is suitable. A gravel tray containing water can be placed under the plants to increase humidity levels around the plants. Make sure the bottoms of the pots are above the level of the water. Daily misting is also helpful.

Frequency of watering depends on the size of the plant and pot, type of pot (plastic or clay), potting medium utilized, relative humidity, and amount of misting. Orchids generally prefer to dry out well between waterings. If the roots are kept wet for more than a few days they may rot. Seedlings or plants with fleshy roots or soft foliage usually prefer constant moisture.

In nature, most orchids are epiphytic; that is, they grow attached to trees with the roots hanging loose in the tropical jungle air. (They are not parasites, however.) They usually receive a good rain once a day and then they dry out. To simulate this in the home or greenhouse we use potting media such as fir bark, osmunda fiber, tree fern fiber, or special orchid potting mixes that allow good air circulation in the root area. These potting media can be obtained from an orchid supplier.

Orchids planted in orchid potting mixes or fir bark need to be fertilized while those in osmunda fiber need very little fertilization. For those that need it, a light feeding of 30-10-10 (1/4 tsp. per gallon) or 15-5-5 (1/2 tsp. per gallon) each time the plants are watered is beneficial. Substituting the use of fish emulsion for fertilizer every other watering will also benefit your orchids. Reduce the use of high nitrogen fertilizers during the winter months when plants are resting.

In the Midwest, orchids may be placed outdoors during the summer months. Place plants on stones or wood in shaded areas. Make sure they are protected from drying winds and mist them on hot days. Bring them back in the house in the fall when temperatures drop to 50 degrees.

If this piques your interest, the names of some of the many books written on the subject follow. Many of these books are available at public libraries or bookstores.

Orchids as House Plants                     Orchid Growing Illustrated
Rebecca Tyson Northen                       Brian and Wilma Rittershausen

Home Orchid Growing                         Growing Orchids (series)
Rebecca Tyson Northen                       J. N. Rentoul

Culture of the Phalaenopsis                 Amer. Orchid Society Bulletin
Orchid                                      (monthly publication)
Bob Gordon

This article originally appeared in the June 5, 1991 issue, pp. 99-100.


Prepared by S. Schouten, Department of Horticulture
Iowa State University, Ames, Iowa.
This information subject to a usage policy.
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Last updated 12/31/97 by John VanDyk
http://www.ipm.iastate.edu/ipm/hortnews/1991/6-5-1991/orchids.html