Moth Orchids


With the holidays behind us, winter seems to stretch out as far as we can see. I don’t know about you, but I’m more than ready for a tropical vacation! We can’t afford tickets to a balmy beach or verdant rainforest, but I can manage to plunk down a mere $19.95—or less—for a blooming orchid. My imagination will have to supply the rest.

Phalaenopsis orchids are the most common orchids for sale as houseplants. Orchid specialists off-handedly refer to them as “Phals.” Their common name of Moth Orchid is due to their pair of large, wing-like petals. Flowers come in pinks, white, yellow, apricot, and bi-colors. Some have stripes. And plants range in size from minatures with 1-inch blooms to full-sized plants a foot or more across.

8 x 10 Phalanopsis2

While some orchid species are difficult, if not impossible, to grow indoors, Phalaenopsis orchids are perfectly suited to the same conditions that make us comfortable. No wonder they’re so popular.

The first consideration for growing any houseplant is light. All plants need enough light to photosynthesize, but some need more than others. Too much and the leaves will scorch. Too little and they won’t bloom. And if they’re kept too dark, the plants will slowly starve to death. Dark green leaves are one indication that the plant is not getting enough light.

These orchids prefer bright but indirect sunlight. An east window is ideal. So are south or west exposures, if the light is mitigated by sheer curtains. I even used waxed paper taped to the glass, and while it didn’t look that great, the plants loved it.


Another consideration is room temperature. While many orchids are native to the tropics, different species are found all over the world. Some even live on snowy mountaintops, such as the Yellow Lady’s Slippers we have here on the slopes of Pikes Peak.

Happily, Phalaenopsis do best with temperatures in the 60s at night, and the 70s in the daytime. We don’t keep our house quite that warm during cold winter days, but my plants haven’t complained. I keep them some distance from the windows, which would be too hot in the summer and too cold in the winter, and they do just fine.

Unfortunately, along with winter heating comes very dry indoor air. My moth orchids would prefer a humidity level of 50% to 70%—higher than the 20% that is typical in our home. You’ll hear that you should place the plants on a tray of wet pebbles, but that doesn’t help as much as we could wish. Short of humidifying the whole house, or pointing a  tabletop humidifier at your plants, there’s really not much we can do.

Talk of humidity brings us to watering. This is the point at which most gardeners fail. Watering orchids is a bit tricky. For one, they absolutely hate to have soggy roots, so providing perfect drainage is essential. That’s why the plants are grown in bark, rather than potting mix. Also, be sure to pour off any water that accumulates under the pot, especially if they’re in a decorative outer container that doesn’t have drain holes.

Phalanopsis orchid LAH 032-001

I water my plants about every seven to ten days. That may not seem like a lot, but remember that these are epiphytes. They usually grow suspended above the ground in the crotch of a tree branch. Allow them to almost dry out between waterings. You can tell they’re ready for another drink by hefting the pot. A well-watered pot will be noticeably heavier. Another option is to pull out the plant label and see how dry it is. If there’s no dampness clinging to the plastic, it’s time to water.

I use room temperature water. A lot of websites recommend adding an ice cube to the pot, but that shocks the roots of these tropical plants. How would you like to be doused with ice water? Instead, I fill a large bowl with water and fertilizer (more about feeding in a moment), then submerge the pot for several minutes. Then lift it out and let it drain thoroughly. Whatever you do, avoid softened water, which contains salt.

Orchids are slow growers, and as such they don’t require much fertilizer. You can buy specialized orchid food, but any water soluble, multipurpose houseplant fertilizer is fine. I fertilize once a month at half strength. After the plants have bloomed, I give them a rest for several months before resuming feeding.

Because they grow so slowly, moth orchids won’t need repotting very often. However, the bark eventually disintegrates and needs replacing. Pull the plants from the pot and gently remove the old bark. Then replace the plant in its pot and add new bark, nudging it into place among the roots. I soak the bark before I add it, but you could do it afterward as well. These orchids don’t mind being root bound, and it’s perfectly fine for the roots to escape their pot and grow up into the air. Just make sure they get wet when you water.

One of the amazing traits of Phalaenopsis orchids is how long they bloom. I’ve had flowers last for up to six months! When they finally die and fall off, you can cut the spike back, or leave it in place. A new flowering spike often grows out of the old one, reducing the time the plant is out of bloom. If the spike turns brown and crunchy, go ahead and cut it off. The plant will form a new one. Just wait and see!

One thought on “Moth Orchids

  1. My uncle was a career Air Force guy, and got interested in orchids during one of his stationings. When he got more setttled, he built a custom “Orchid House”. I love plants; wild bonsai and mushrooms. Whenever I see orchids for $19.95, I am reminded that just some decades ago, those same plants, if they could be found, would be in the thousands! Enjoy, orchids are wonderful, and we have finally figured out how to cultivate them. Thank you for your fun site.

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