Temperature is another major variable that will influence your relative success (or lack thereof!) keeping orchids.
Some orchids are very sensitive to temperature. For example, Phals. shouldn’t be kept where the lows are below about the mid-50s. Fifty-five is frequently cited as the acceptable low. This isn’t a problem to maintain because my Phals. never go outdoors. And our inside house temperatures range from a high in the mid-80s in the summer to lows in the low- to mid-60s at night in the winter. This is a perfect range for Phals. So if they are watered correctly, and not exposed to too high a light level, they are the perfect “house orchid.”
Cymbidiums, on the other hand, need temperatures in the mid- to low-40s or they won’t even set flowers. I keep my Cymbidiums outside from Spring through Fall. At the extremes, I keep an eye on the lows each night. If they go down to the low 40s, I just leave the plants in place. They’ve even accidentally been left out in high 30s with absolutely no sign of damage. But I try to not expose them to anything lower than 40. In the Fall, I watch the lows every single night. I WANT them to have as many nights in the 40s as I can give them. They get treated like yo-yos occasionally, being brought in, then back out. In, then out. If we get a sudden cold snap, they come inside. If we go back to a period of relative temperature stability with nights in the 40s, they go back out. I have four Cymbidiums. I typically manage to get 2-3 of them to bloom each season. Before I found out about their need for low temps, I couldn’t get any of them back into bloom from the time they were purchased at a supermarket (for $5 per plant, I might add! They were near the end of their flowering and the store had to sell them off quickly or lose them. I love a bargain. For $5 I can afford to have some live and some die!)
I used to put a lot of my orchids outside on racks in the summer. The problem in central Kentucky, however, is that its possible to have stretches where the highs of the day are in the mid- and occasionally upper 90s. And that’s too hot for many orchids. I tried keeping them in the shade, but then I realized I was simply making more work for myself trying to manage something I couldn’t manage – Mother Nature! I CAN control my inside temperatures. And I can control light level simply by where I position the orchids. So with the exception of my cymbidiums, all of the other orchids in my collection stay indoors year ’round.
Pahphiopedilum’s, often referred to as “slipper orchids,” come in what they call “cool” Paphs and “warm” Paphs. These are relative terms, of course. The “cool” ones like what would be in effect the temperatures in a cool house (60s, 70s) and the “warm” ones would do well where temperatures go up into the 80s. At least that’s what I’ve read. And the reason it’s “what I’ve read” is because this is the ONE orchid for whatever reason I have simply never been successful at raising. Besides liking a little higher humidity than many, their temperature range is not appreciably different from my house. And the watering is not appreciably different from my Phrags. – keep moist, run water through to flush, water more frequently if kept in bark, less if kept in moss, etc. To boot, they like lower light and can even survive extremes of temperature for short periods of time. So for the life of me I don’t know why I can’t keep them. That’s actually a misnomer. I CAN keep them. I just can’t get them to bloom – EVER. I have purchased a number of them. They are beautiful plants with attractive leaves and very pretty flowers with incredible variety. I’ll buy one in flower, read everything I can about it, try to keep it EXACTLY the way it is supposed to want to be kept…. it just won’t set flowers. Maybe now that I’m using Hawaiian Bud & Bloom…. Maybe I should try again!
Here’s the bottom line… Unless you intend to put SERIOUS time and potentially money into facilities to provide an environment – including temperatures – other than what your family enjoys anyway, limit yourself to orchids that like YOUR temperatures rather than having to try to figure out how to accommodate THEIRS! My Phals and my Cattleyas (and crosses) love our normal house temperature range. And that’s good enough for me!