Jason,

Anything below 50 for an extended period is questionable, especially if using spagh. I've had mine out under a protected patio when the temps dropped into the upper 40's at night, but again it was a semi-protected patio so the temps may have been a little higher under the eaves. I think you are right on the teetering point as far as temps. I've generally heard 55-60 for a minimum temp for phals for any extended period.

Good luck,

Bob

What's the lowest temp the phal will see and how often will they see it?

I will tell you my phals routinely see temps in the 40s and occasionally thirties without a problem this time of year. And this is in several different growing evnironments. though as bob noted conventional wisdom says don't let the get below 50.

It all just depends.

Some of mine spend winter around cacti which I try to keep as cool as possible, though they are all in the apartment, not a greenhouse. They can be pretty sturdy if kept drier and given enough sunlight. Again, these are probably not the kind of conditions they thrive in, but my choices are limited and my phals have to put up with what i can provide... Those that are in bloom or putting out spikes are, of course, moved to much warmer places.

terp, I'm not sure what kinds of temps it's going to see. I kept it inside last night because I am extremely nervous when it comes to leaving my plants out in the cold. The whole weekend is expected to have a high of 65 and lows in the low 50's/upper 40's. There is a weather system moving through and we should be back in the 70's and sunny in a few days. Would you suggest putting a space heater in the greenhouse? Or is that a silly question?
Bob, That's why I brought it inside because I felt I was right on the teetering point And this is the only orchid I have and I don't want to lose it. I had a nightmare a while ago in which this orchid got stolen. Even though it was just a dream, I have never before experienced such a great sense of loss. lol

Apart from the temps, there might be other problems such as low humidity. My instructions here at orchid shows is never, ever put them outside....and outside includes glasshouses not especially set up to grow Phalaenopsis.

Optimum temperature range is something like 60 to 85F daily with moderate humidity levels.

Okay then on that note I think it will remain an indoor plant. It has been doing fantastic in my north window until my dad parked a gigantic trailer in front of the window, causing light levels to be extremely low. That's why I was considering keeping it outside, so it could have more light.

Too bad about your nightmare. I've had bad dreams about forgetting about a few orchids for months, then finding them alive but barely making it.

If your Phal gets enough supplemental light in the north window, it will be happy - gigantic trailer and all. Some people grow orchids in their windowless basements.

At Home Depot, for instance, you can get their 200W incandescent equivalent, daylight spiral CFL bulb, put it in a brooder light fixture with a porcelain base, and clip the fixture to something handy. If nothing is handy, you can make a simple stand from PVC pipe from HD.

Our local HD doesn't carry a daylight spiral CFL stronger than about a 100W incandescent equivalent - the 200W equivalent is available only online, so you might want to call ahead, if you go with HD.

My orchid room last winter:

{{gwi:204749}}

Brooder light fixture with porcelain base @ HD: http://www.homedepot.com/p/Commercial-Electric-150-Watt-Incandescent-Brooder-Clamp-Light-CE-303PDQ/100354517

WhiteCat8

Here is a link that might be useful: 200W equivalent, daylight spiral CFL bulb, HD

Your best option is to buy another orchid, just in case :-)

With your added comments, I'd say you could probably keep it in the greenhouse and only bring it in on those few AR nights that drop below 50.

If you look at some recent threads, most phals need a 15 degree temp drop from day/night in the fall to induce spikes/blooms. Hard to achieve indoors without very large temp swings (leave outside until early fall or open window at night here in Ohio). To sum it up, I think the greenhouse may give you the temp changes required for blooming most phals, just be careful on those few nights were temps drop below 50.

Again good luck and heck buy another orchid,

Bob