It’s Time to Move Orchids Outdoors for Summer
WHILE MOST OF US PROBABLY consider some types of orchids to be suitable houseplants and the majority to be greenhouse subjects, all of their ancestors came from the great outdoors. For most, it was the tropical outdoors to be sure, but even though we have adapted them to culture in modified indoor environments of one type or another, many will thrive on and appreciate a few weeks or months outside during the warm season when the weather in some areas of the North is warm and balmy.
Before you hastily ship off your orchid collection to a backyard version of horticultural summer camp, put some thought into your plan. It is important to take a bit of time to compare the indoor environment your orchids enjoy to the outdoor situation in which you will summer them.
First and foremost, carefully evaluate the amount of light your plants are receiving in their protected environment with the amount they will receive in the location you propose to use for them outdoors. This is especially critical for indoor growers who cultivate their orchids on windowsills or under artificial lights. The brightest indoor growing situations are, at best, comparable to what most would call a partially shaded environment outside.
Plants from rather protected indoor environments may actually thrive better outside if grown in a mostly shady outdoor location that might receive direct light only for a short time in the early morning or evening when the sun is low in the sky. Certainly there is no quicker way to sunburn or kill most any sort of indoor plant than to set it in direct sun outside for even a few hours. Consider starting your plants off in a rather shady spot and moving them to brighter, partially shaded locations gradually. Obviously, the type of orchid will to some degree dictate the amount of light it can and will tolerate outside.
Temperature is an important factor too. You must consider not only the low temperatures, but also the high ones. It is safe to say that many tropical orchids can tolerate chillier temperatures than most of us suppose. Hobbyists who grow their orchids outdoors in South Florida are seldom concerned when the nighttime temperatures slip into the 50s F in the winter season — a common occurrence. When the occasional nights in the 40s come along, they may move some of the more cold-sensitive types indoors, such as some of the dendrobiums and certain members of the vandaceous clan, but often leave the cattleyas out in the chill. Still, orchids that are accustomed to a cozy life should probably be kept inside until night temperatures are reliably 60 F (15 C) or higher, unless they are cool-growing types.
Excessive heat can be as damaging to your plants as cold. If you live where summer high temperatures are frequently in the mid 90s F 35 C) and higher, be certain that your plants have adequate shade and humidity to help them endure those warm hours. Some orchids that prefer intermediate temperatures and certainly those orchids that are cool growers will likely suffer if forced to endure many days or weeks of such conditions.
Some parts of the United States are humid in summer, and indoor orchids will relish that. Growers in more arid regions may find the drier air a handicap.
If you move your orchids outside, you will need to carefully monitor their watering needs. Relative humidity, wind speed, temperature and rainfall will combine to affect how quickly your plants and their growing media dry out. You may need to water them much more or much less than you were accustomed to indoors.
Protection from the elements may be necessary or advisable as well. Consider what a week of daily rain could do to your plants’ roots, or how a hailstorm or severe wind could quickly turn your lush plants into chopped salad. A simple shelter or bit of waterproof covering overhead could solve the problem.
Orchids outside must be regularly checked for pests. Do not set the orchid pots on the ground. Use benches or shelves for your plants to avoid providing many insects and soil-borne critters a “leg up.” You will be wise to give all plants summered outside a good spraying and their growing medium a drench with an insecticide before returning them indoors at the end of the season.
Finally, consider which plants in your orchid collection are the best candidates for a summer vacation outdoors. Sturdy, mature plants in heavy pots will likely fare best. If you grow your collection in plastic containers, consider slipping each into a heavier clay pot for its outdoor excursion to counteract the tendency of orchid plants to be top heavy. Miniature or immature plants in small containers will tend to dry out quickly and may be unable to withstand stress. The same could be true for mounted plants as well, unless you live in a humid locale or are willing to commit to their frequent watering needs.
This may all sound like a lot more trouble than it is worth, but the effort could pay big dividends for some orchidists. Indoor growers who have the right outdoor summer climate and situation will likely discover that they can use the warm months to their advantage in cultivating orchids with higher light requirements than they could ordinarily supply with a year-round indoor routine. Since many orchids produce their new growth in summer, an optimum outdoor environment at this time will likely produce stronger plants that will flower better next autumn, winter or spring.