Documents: Special Interest: Orchids:

Get in the Know to Grow Orchids
by Dan Gill
by Dan Gill

email: dgill@agcenter.lsu.edu

Dan Gill earned B.S. and M.S. degrees in horticulture from Louisiana State University in Baton Rouge, and is an Associate Professor in Consumer Horticulture with the LSU AgCenter.

He is the spokesperson for the LSU AgCenter’s Get It Growing project, a statewide educational effort in home horticulture utilizing radio, Internet, TV and newsprint. Gardeners throughout Louisiana read his columns in local newspapers, watch his gardening segments on local TV stations and listen to him on local radio. In the New Orleans area, Dan appears weekly on the Channel 4 Morning News, writes a weekly gardening column for The Times-Picayune and hosts the Saturday morning WWWL Garden Show, a live call-in radio program.

Dan is co-author of the Louisiana Gardener’s Guide and author of Month-by-Month Gardening in Louisiana. His “South Louisiana Region Report” and “Only in Louisiana” columns appear monthly in the Louisiana Gardener Magazine.


May 18, 2008

The orchid family contains more species than any other family of flowering plants. They have adapted to climates ranging from the Arctic Circle to the equator, but most of the orchids we grow as ornamentals are from the tropics. No other group of plants can provide more beauty, color and diversity.

Blooming orchid plants are increasingly available and reasonably priced. Many people who have not really thought of growing orchids may be moved to buy one on impulse. Orchids are also popular as gifts these days, as well.

Most of the tropical orchids we grow are epiphytes. Epiphytes, such as our native Spanish moss, are not parasites and simply use the tree as a base to grow on. Although rainfall is plentiful in most habitats where tropical orchids grow, water does not linger up in the trees, and plants must be able to survive until the next rain. For this reason, many orchids have tough, leathery leaves to reduce water loss and water storage organs called “pseudobulbs” to store water.

Orchids also grow in the ground, and these are called terrestrial orchids. They are not as common in cultivation as epiphytic orchids, but we do grow some terrestrial orchids such as the Chinese ground orchid (Bletilla striata), nun’s orchid (Phaius tankervilleae) and Spathoglottis orchids. These can be planted in pots of potting soil or in garden beds.

Most of the orchid species that are native to Louisiana (and temperate climates in general) are terrestrial. We do have one native epiphytic orchid in South Louisiana, the fly speck orchid (Epidendrum conopseum)

Most cultivated orchids’ adaptation to life in trees makes them relatively easy to keep alive. The problem is that gardeners often have trouble getting them to bloom again. Most orchids bloom once a year.

It is important to remember there are many different kinds of orchids that come from a wide variety of habitats. Some prefer full sun while others like shady conditions. It is important to know the kind of orchid you have in order to know how to take care of it. If you don’t provide your orchid with enough light, it will not bloom well.

You also must know the kind of orchid you have in order to determine how to water it and the temperatures it needs – or even if it will grow here. Orchids native to higher elevation where the temperatures are cool would do poorly in Louisiana’s steamy summers.

Because it is so important to know what kind of orchid you have in order to learn how to take care of it, always check to see if there is a name tag in the pot when you purchase an orchid. If there isn’t a name tag, check with the staff at the nursery or florist where it is for sale. If you’re giving an orchid as a gift to someone who is not familiar with orchids, do an Internet search using the name on the tag. Then you can find the appropriate growing information, print out a copy and provide that with the gift.

Once you know the kind of orchid you have and the growing conditions it needs, it’s relatively easy to grow. Indoors, they will thrive in a brightly lit window facing east, south or west. But a shady north-facing window may not provide enough light to encourage blooming.

You can “summer” your plants outside during warmer times of the year. After nighttime temperatures reliably stay above 60 degrees, move them to an outside spot that receives the appropriate light. No more than a couple of hours of morning sun or dappled light (too much direct sun will burn the foliage) is needed for shade-loving orchids such as phalaenopsis and paphiopedilum, while direct sun for most of the day is preferred by sun loving orchids such as vandas. Spending time outside also provides a temperature drop between day and night of at least 10 degrees and good air circulation, which orchids prefer.

Orchids that are epiphytes require a special orchid mix, not potting soil, when grown in containers. Orchid mixes generally are based on chopped fir bark these days. Many orchids should be potted in a medium-grade bark or medium-fine bark mix (medium bark with perlite and chopped sphagnum moss added).

When watering, you must run water through the mix until it is properly moistened. This is best done indoors at the sink, allowing warm water to flow through the mix until it is thoroughly moistened. Outside, just use a hose. Orchids that do not have water-storage organs, such as phalaenopsis, should be kept moist and allowed to dry only slightly before watering.

To keep your orchid growing vigorously, fertilize it regularly from spring to early fall using a soluble fertilizer (such as 20-20-20) according to label directions. This can be accomplished by dunking pots individually into a bucket of fertilizer solution or applying a fertilizer solution with a watering can. You also can use a hose-end applicator to fertilize a lot of plants outside or in a greenhouse.

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