Smith County Horticulturist
I availed myself to references, books and magazines, and became thoroughly confused, and nearly convinced that folks without greenhouses were not meant to enjoy these botanical wonders, except as corsages on special occasions. Killing a few along the way reinforced my notion that special conditions were needed to grow orchid.
Proper conditions needed to grow orchids are diverse as the ecological habitats from which they come. This is one reason for my original confusion. Different species have a range of temperature and light requirements. Some require cooler temperatures; others thrive in warmer conditions found in East Texas. Some require very bright light, even some sun, while others do better in more subdued lighting.
I suggest to start with one or two of the more easy types of orchids, and once successful, venture out from there.
The moth orchid, Phalaenopsis, is one of the easiest to grow based on light requirements. The moth orchid was designated a TexasSuperstar plant a few years ago. A former orchid researcher at the Texas A&M AgriLife Research Center in Weslaco helped moth orchid to become even more readily available. It is now is found in grocery stores, lumberyards and nurseries.
In a greenhouse, provide shade to permit no more than 800 to 1,500 foot-candles of light. No shadow should be seen if you hold your hand one foot above the plant's leaves.
TEMPERATURE — Phalaenopsis orchids should be grown ideally above 60 degrees at night and between 70 and 82 degrees during the day. Temperatures below 78 degrees for three to five weeks with good light are needed for initiating flower spikes. If you keep your plants indoors, take them outside (but in the shade) in early fall for a few weeks to promote flowering. Bring them in before the night temperatures fall into the 50s.
Widely fluctuating temperatures and low humidity can cause bud drop on plants with flower buds ready to open.
WATER — The growing medium should never be allowed to dry out. Plants should be thoroughly watered and then not watered again until nearly dry. In the heat of the summer, this may be every two to three days, whereas during the winter, it may be every 10 or more days.
To test the soil for orchids planted in a peat based media, stick a pencil into the media as you would stick a toothpick into a cake to test for doneness. If the pencil comes out with peat on it, or is wet, do not water.
Do not allow water to accumulate in the leafy crown very long and do not allow pots to sit in standing water.
FEEDING — Fertilizer should be applied regularly, especially during warm weather when plants are growing. Apply a half-strength water-soluble, complete fertilizer every two weeks. Reduce this frequency in winter.
POTTING — Potting is best done in late spring or early summer after blooming is finished. Pot Phalaenopsis orchids in a well-draining mix, such as fir bark, tree fern fiber, types of stone, sphagnum moss, or combinations of these. Orchid fanciers have their favorite mixes, and are always trying new recipes.
Root rot will occur if plants sit in an old, soggy medium that has broken down and holds more water than it used to. This is probably one of the biggest factors in killing orchids. So repotting is necessary.
Young plants should grow fast enough to need repotting yearly and should be potted initially in a fine-grade medium to allow good root contact. Mature plants can grow in the same pots for two years, potted in a medium grade mix. They can stay in the same pots for years, provided the medium is changed as it breaks down.
To repot, remove old medium from the roots, trim soft, rotted roots, and spread the remaining roots over a handful of medium in the bottom of a pot. Fill the rest of the pot with medium, working it through the roots, so that the junction of the upper roots and the stem is slightly below the medium.
Avoid leaving large air pockets in the pots. Use a stick to push the medium between the roots. Keep plants shaded and wait for a couple of days before watering.
Keith Hansen is Smith County Horticulturist with the Texas A&M AgriLife Extension Service. His web page is http://EastTexasGardening.tamu.edu His Blog is http://agrilife.org/etg Texas.