Backyard Gardening

By Kathryn Dorman

I have always considered orchids to be exotically beautiful. I believed that they
would be very tricky to grow and expensive. I was content to enjoy my irises, which are
sometimes called the ‘poor man’s orchids.’ Recently, however, I found a miniature orchid
plant on clearance for less than $10, so I bought it. I knew I’d better quickly do some
research on orchid care before I killed my new plant!

All orchid species belong to the Orchidaceae family. According to the American
Orchid Society (AOS), there are at least 20,000 orchid species, and many varieties of each
species. Most orchid species grow in the understory of tropical rainforests. However,
orchids are native to “every country in the world and every state in the United States,
including Alaska. No plant family is more diverse.” Orchids come in every color except true
black. My favorite is the flower that typifies the purple pink ‘orchid’ color (see Photo 1). The
miniature orchid plant I bought is less than a foot tall. Other orchid species can reach
lengths of 20 or more feet (https://www.aos.org/orchids/orchid-care.aspx).

In 2019, I took a tour of Longwood Gardens, near Philadelphia. They have orchids
growing along one entire wall (see Photo 2). This is where I learned that REAL vanilla
comes from the seed pods (beans) of orchids! Vanilla orchids (Vanilla spp.) are native to
Central and South America. Today, most of the world’s vanilla is grown in Madagascar and
Indonesia.

Orchids are not parasites. Although some orchid species grow in soil, most are
epiphytes, or air plants. In their native habitats, epiphytes grow on trees, merely using them
as support structures. According to the Rainforest Alliance (RA), orchid roots form a
symbiotic relationship with a mycorrhizal fungus. The mycorrhizae grow inside the orchid’s
roots, converting nitrogen from the air to a form which the plant can use to make its
proteins. The fungus gets energy from the orchid through photosynthesis
(https://www.rainforest-alliance.org/species/orchid/).

According to Iowa State University (IASU), there are six orchid genera which may be
easier to grow than others, including corsage orchids (Cattleya spp.), Cymbidium orchids,
cane orchids (Dendrobium spp.), dancing lady orchids (Oncidium spp.), lady slipper orchids
(Paphiopedilum spp.), and moth orchids (Phalaenopsis spp.). Moth orchids are the most
readily available to home gardeners (https://www.extension.iastate.edu/news/yard-and-
garden-growing-orchids-home).

The motto for keeping orchids alive could be “less is more.” This holds true for the
growing conditions of soil, nutrients, light, and water. Epiphytic orchid roots have evolved to
require more oxygen than most other plants. Use a lightweight, well-aerated, mixture of
bark chips, pebbles, and loosely packed organic matter. Since the organic matter can
break down over time and retain too much water, replace the potting medium every two
years or so. Orchid roots may get chemically burned if too much fertilizer is applied too
often. Keep in mind that in nature, orchids get their nutrients from rainwater and the
mycorrhizae living in their roots. Orchids only need a weak (half to quarter strength)
solution of fertilizer. Choose a fertilizer specifically labeled for orchids. To prevent root
burn, water first to wet the roots, then apply the fertilizer.

Orchids require indirect light, and windows that face south or east tend to work best.
Too much direct sunlight can burn the leaves. West facing windows may provide too much
sunlight. North-facing windows usually don’t provide enough light for the orchid to flower.
Orchid leaves should be bright greenish yellow. If they are dark green, the plant is not
getting enough light. Orchids will benefit from being set away from the window, and/or from
being shielded with a sheer curtain, reducing light intensity.

Overwatering may be the quickest way to kill an orchid plant. If the roots are too wet
for too long, they will rot, killing the plant. Use lukewarm water. Let the orchid plant dry out
completely between watering. Please note: Many experts advise AGAINST watering with
ice cubes, since this can cause frost damage, and/or allow the roots to stay damp,
especially if the orchid is growing in sphagnum moss (IASU).

Ironically, orchids do require high humidity. Set the orchid pot in a ‘humidity tray,’
which consists of a shallow container filled with sanitized pebbles and water. The bottom of
the pot should sit above the water level.

The most common orchid pest infestations include aphids, mealybugs, scale, and
spider mites, as well as infections of microscopic bacteria, fungi, and viruses. Some pests
can be controlled with repeated applications, using cotton swabs, of diluted isopropyl
(rubbing) alcohol (AOS).

Many orchid species require a single species of bee, bird, etc. to pollinate their
flowers for seed production. Many pollinators may now be threatened with extinction by
deforestation and other environmental concerns. Many orchid species may consequently
become endangered as well (RA).

Orchids are becoming a popular option for the home gardener. They are readily
available, often for a reasonable price. As long as you remember that “less is more,” they
can also be somewhat easy to grow. Orchids are not just for people with greenbacks
and/or green thumbs anymore!

Kathryn Dorman has been a Penn State Extension certified Master Gardener in Clinton
County since 2017. She can be reached at clintonmg@psu.edu, or through the Clinton
County Master Gardener Hotline at (570) 858-0198.