Taking care of orchids
Orchids are gaining popularity in our area each year. I really enjoy growing them and the fact that when they do bloom, they hold their blooms for a very long time. Months, in fact. They are easy to raise and when you know a few tricks, it is easy to get them to bloom again and again. There are many fellow gardeners who love to raise them as well and it is not necessary to have special growing conditions to raise them either.
Orchids have been sold locally in our Marshall area for a number of years. There are some that are a bit more tricky then others, and there are two that are quite easy to grow. Among the easiest to care for as houseplants are species and named cultivars of Phalaenopsis (known as moth orchids) and Paphiopedilum (known as ladyslippers — though they’re not the ladyslippers that grow outdoors in Minnesota).
Both Phalaenopsis and Paphiopedilum orchids are known for their long-lasting flowers. Individual moth orchid blossoms may remain open and fresh for two months or more.
The key to get orchids to bloom and to keep them healthy is to understand how they grow in the wild. Phalaenopsis orchids are epiphytes, which means in nature they grow in the branches of tropical trees, clinging to them for support while absorbing moisture from the surface of bark that is wet from dew and from rainfall. This means they should be potted in special orchid mix made of bark chunks that won’t absorb much moisture. They will not tolerate soggy roots, so when you water, that water should whoosh right through the potting medium. This potting soil is available in our area in one of the local hardware stores as well as special orchid fertilizer. Since I do not like promoting one place over another, you will have to do your own homework where to find these materials.
Paphiopedilum orchids are terrestrials or soil-dwellers. They should be potted in a more typical houseplant mix that holds some moisture but still drains well. Neither type of orchid should need repotting for at least a year after they’re purchased. If you are not sure which orchid you have, see the pictures along with this column. They do have vastly different leaf styles.
While neither Phalaenopsis nor Paphiopedilum orchids need extremely high humidity, they do benefit from added humidity in winter. Placing pots on top of gravel in moisture-filled trays might help. You just need to be careful that their pots are set above the water line so no moisture will be drawn in through bottom drain holes. Room humidifiers also help increase relative humidity without jeopardizing orchid roots.
Neither of these orchids should be allowed to dry out completely between waterings. How often you water will depend on how bright their growing conditions, how humid, and how warm it is, all factors that impact how fast the potting mix will dry. Always use room temperature or barely lukewarm water that will not shock the orchids’ roots, and avoid softened water if at all possible. Softened water is tough on many houseplants particularly orchids and spider plants. I can get my “hard” water from our barn and I leave it in a 5-gallon bucket in the basement which keeps me in “good” water for quite a while.
According to Deb Brown, who was with the U of M Extension, “Make a point of holding the container over a sink or washtub and watering thoroughly so moisture drips right through and is discarded. Lift the pot right after you’ve watered to get a feeling for its weight, then hold off watering again until it feels lighter. Don’t rely on the calendar to tell you when to water. Use a special orchid fertilizer such as 30-10-10, mixed half-strength, once a month — more often during growth spurts in spring and summer. Every three months fertilize them with a complete fertilizer containing minor elements along with the major elements, nitrogen, phosphorus, and potassium. Almost any ratio of the major elements in this complete fertilizer is acceptable.
“All orchids need good light, but they cannot stand much of the heat which usually accompanies high light intensities. You may reduce temperatures in south or west-facing summer windows by drawing sheer curtains across them. If daytime temperatures exceed 90 degrees, you’ll have to move the plants to a cooler window such as an east-facing exposure. It’s doubtful whether orchids would bloom in a north window.” I have also moved my orchids outside once the weather is fairly stable which in our area means June. I leave them outside until threat of frost. They stay in a well shaded garden so they don’t burn and they do quite well. I make sure to remove the pots and keep the orchid in the plastic sleeve to avoid having them sitting in water during heavy rain spells.
Brown says, “Orchids may fail to bloom if night temperatures are very close to daytime levels. A two-week period in spring or fall where temperatures at night are kept 10 to 15 degrees cooler than during the day should initiate flower development, assuming the plant receives adequate light levels. Besides failing to bloom when night temperatures are too high, Phalaenopsis and Paphiopedilum orchids will not bloom if light levels are too low or too high. Low light is often accompanied by the presence of dark green foliage. Too much light may result in leaves that are pale yellow-green and bleached looking.
Orchids may also fall prey to common houseplant insect pests such as mealy bugs, scale, and spider mites. If your plants have a problem that doesn’t respond to washing or wiping with an alcohol dipped cotton swab, check your local garden center for houseplant pesticides that are labeled for use on orchids. Be sure the plants are not moisture-stressed when you treat them, and keep them out of direct sunlight for two or three days afterwards.”
Much of the information for this brief was taken from Horticulture Fact Sheet #46, 1977: Orchids for the Home Environment, by Steven J. Murray and Deborah L. Brown. https://www.extension.umn.edu/garden/yard-garden/houseplants/easy-orchids-to-grow-as-houseplants/ For more information on gardening, contact me at firstname.lastname@example.org