You don’t need high temperatures to grow orchids. There is a common belief among those who have never grown orchids that they require an excessively hot greenhouse, imitating conditions of the tropics. This is a mistaken idea.
Temperature Requirements For Orchids
Many orchids can be grown in a cool house – a greenhouse where temperatures of 45 degrees to 55° degrees Fahrenheit are maintained at night.
Even those varieties that require the warmest conditions are not grown at temperatures higher than 65° degrees Fahrenheit, and for most, a temperature of about 60° degrees to 62° degrees Fahrenheit is considered the night requirement.
Day temperatures, of course, are usually ten or more degrees higher due to the heat generated by the sun.
Cool temperatures – 45° degrees to 50° degrees Fahrenheit – are ideal for a considerable number of orchid genera. Among them are the hardy native cypripediums, “green-leaved” varieties of semitropical cypripedium (paphiopedilum), and all cymbidiums.
There are others, too, such as epidendrons, one of the spray orchids which many prefer to the larger cattleyas.
Growing Hardy Native Cypripediums
Of the cypripediums, some of the most beautiful and interesting are hardy in many parts of the United States and Canada. Several of these native orchids can be forced into a cool greenhouse like you would hardy bulbs.
I have had success in the two species with which I have succeeded are C. spectabile, the queen’s lady slipper, and C. candidum, snowshoe.
Good strong clumps are potted in the fall and placed in a cold frame or trench outside until late winter. Then, they are brought inside and placed in the coldest part of the greenhouse and allowed to develop slowly.
After flowering, they can be allowed to grow, and when mature, they can be planted in the wildflower garden, where they can be expected to bloom the following spring.
Semitropical Cypripediums
Semitropical cypripediums (sometimes called paphiopedilum) comprise a large group, considering the many species and now numerous hybrids.
They are not only the most beautiful orchids, having queer shapes and many color combinations and markings, lines, and spots, but also exhibit exceptionally long-keeping qualities.
They will last four to five weeks either on the plants or as cut flowers. Corsages are especially beautiful when several of the same or different varieties are arranged together.
Green-Leaved Varieties of Semitropical Cypripediums
Without becoming too technical, there are two general classes of semitropical cypripediums: the “green-leaved,” grown at temperatures of 50° degrees Fahrenheit at night, and the “mottled-leaved” kinds requiring a warmer 60° degrees Fahrenheit greenhouse.
The green-leaved varieties do best when grown in a partially shaded greenhouse. They should never be allowed to become dry at the roots, and care should be taken to water in the forenoon so that water will have a chance to evaporate from the base of the leaves.
This prevents basal rot. Overhead spraying may be advisable during the hot, bright days of summer.
Potting Materials For Green-Leaved Cypripediums
Various combinations of potting materials are used. Some growers use brown osmundine fiber alone, whereas others combine it with sphagnum moss, decayed sods with the fine soil sifted out, oak leaf humus, sand, or small pieces of gravel or broken brick to keep the material porous.
Whatever potting material is used, it is essential to provide adequate drainage with abundant broken crock in the -bottom of the pot, which should have a large hole.
Propagating Cypripediums
Cypripediums are propagated by division and do best when not allowed to become too large before repotting and dividing. Pots from 3″ to 4″ inches wide are usually best, as over-potting is harmful.
Hybrids are produced from seed using the best types of parents. Their production from seed is technically more difficult than other genera, and this appears to be especially true of our native hardy species.
Cypripedium Varieties
Among the cypripediums, C. INSIGNE is one of the best-known species and is often chosen as the plant with which to begin. It is quite pretty, easily grown, keeps well, and is not expensive.
There are several C. insigne varieties Such as HAREFIELD HALL, which is larger, and SANDERAE, a bright yellow that is a cross with C. CALLOSUM, also a good plant. There are also the varieties ROYALTY and THE QUEEN, both of which resemble Sanderae.
Varieties of C. LEEANUM, such as CLINKABERRY ANUM, are especially good. Other good species are C. SIMON (ac-tens), C. LASALLE (Alcibiades), C. AUREUM, C. VILLOSUM, C. CURTISI, and C. CHARLESWORTHII.
C. MAUDIAE is a green and white variety used a great deal for corsages. It has mottled leaves and requires a warmer position, but it is well worth trying, as is C. HARRISIANUM, the first hybrid cypripedium developed. It has mottled leaves but often blooms more than once a year.
If you don’t have a greenhouse, cypripediums may be grown in a Wardian case in the home. They do not require bright sunlight, are not tall growing, and temperature and humidity can easily be regulated to fit their specific needs.
Coll House Orchid: Cymbidiums
Cymbidiums are a large genus of cool house orchids among the family’s most beautiful.
Their colors cover a large range from white to shades of pink, yellow, bronze, brown, green, and chartreuse, but they are seldom solid. They are blendings of various colors with markings, lines, and spots of many colors in the same flower.
One of the attractive features of cymbidiums is that the flowers are mostly borne in curved sprays with several flowers on each. They make the most attractive corsages and can be worn singly or in groups of three or more.
Cymbidiums are a favorite Easter flower, as many varieties, such as the well-known C. pauwels bloom during that season.
Their long-keeping quality makes them ideal for this season, for no matter whether Easter comes early or late, if actually in bloom, they are certain to remain fresh long after the season has passed.
They are often kept either as a cut flower or left on the plant for four to eight weeks. However, cutting them fairly early rather than leaving them on the plant too long is better.
Ideal Climate For Cymbidiums
Since visiting many large commercial growers in California last April, I have become a cymbidium enthusiast.
The climate of California seems especially well suited to their culture both under glass and in lath houses, in which they are grown both in pots and in the open ground.
They are hardy to the extent that at times they withstand a freezing temperature for a short time without injury that is, unless they are in bud.
One of the largest collections I visited was that of Louis M. Boyle, Sr., of Ojai, California, who has acres of cymbidiums in lath houses.
He is the author of “Cymbidium Orchids for You” which illustrates many tine types and describes methods of culture.
Good Compost For Cymbidiums
Mr. Boyle feels it is necessary to grow cymbidiums in good compost. Oak leaf mold is commonly used as a basis, and it is most advisable to make your own.
In addition to the oak leaves, grass clippings and other waste materials such as alfalfa and bean straw, stubble, and a small amount of rotted manure can be mixed in the compost. The potting material should be medium loose, not tight, packed, or lumpy.
Other growers use various mixtures, such as old discarded osmundine taken from other orchids when they are repotted. However, it seems a common practice to add some well-rotted manure to most potting mixtures.
Repotting After Flowering
The best time for repotting is just after the plants have flowered. The pots should be amply large with a large drainage hole in the bottom.
The pots should be thoroughly clean, as should the drainage crock. The less frequently cymbidium is disturbed the better they will flower.
They require some light shading as bright sunshine will easily burn the leaves. The optimum night temperature is 50° degrees to 55° degrees and 60° degrees Fahrenheit in sun heat.
Cymbidiums should never be allowed to become dry, as they have no pseudobulbs to store moisture.
Summer Care
Removal of the potted plants to either a lath house or partial shade of a tree is considered best during the summer months.
It is also considered good to allow the plants to remain outside until the weather becomes quite cool, as the “shock” of becoming cool seems to favor flowering.
When developing buds, however, they should not be allowed to become frosted, or they will not develop.
Red Spider
Red spider is the worst insect pest on cymbidiums, but frequent light sprayings with water will keep them in check.
Thrips are also bothersome at times but can be controlled easily with insecticides.
Cymbidium Selections
The list of cymbidium varieties from which selections may be made is large, and prices vary according to the flowers’ quality and the hybrid’s newness.
My small collection started with a plant of the first hybrid cymbidium developed, a cross between C. eburneum and C. lignum. It is of a pink color and was named EBURNEO LOWIANUM, and is also called C. vietcali.
C. ALEXANDER, a pale pink with rose markings, is good and often used in other hybrids. BUTTERFLY is a yellow-buff marked brown. PAUWELSI, a bronze yellow with brown lip, is a variety found in most collections.
PERI is much grown, and there are many beautiful colors of it. PROFUSION is a deep rose maroon, but plants are expensive. ENCHANTRESS is green with a brown lip. MOIRA rose, flushed brown, is quite inexpensive and a good bloomer.
SICILY is an early blooming green and chartreuse. There are many other good varieties, but seeing the prospective purchase in bloom is always best.
So now, if you possess a greenhouse, even if it runs cool, you can grow orchids. I strongly recommend them.
44659 by Dr. Norman C. Yarian