Hi, Christian; I'm in Monmouth County, NJ, by the shore. Welcome to the "club". In case you haven't seen it already, don't miss Conifers' thread with the step-by-step construction photos and commentary.

I have a few orchids, but cannot by any stretch of the imagination consider myself "experienced" with them. All were happy in the greenhouse this winter, but as soon as things warmed up, I had to bring the neofinetia falcata and sedirea japonica indoors as they seem to prefer cooler temperatures. The rest (1 dendrobium and 1 cymbidium) are outside as I think the greenhouse is too hot; I don't attempt to cool it in summer and there are no plants in it now. When the weather cools down a bit, I'll empty it out completely and clean everything in preparation for the next season.

During the winter, I kept the greenhouse at a minimum of about 50F, and tried to keep it to a max of about 70-75F or so. Inside the greenhouse, I placed the orchids so they'd be shaded from mid-day sun by other plants and they seemed happy with that.

Diane

Thanks for your response. Can I ask you what kind of heater do you use? I assume an electric one. Did you also use bubble wrap? What about a pool solar cover?

I have about 200 hundred orchids -- a huge investment in time and money. I would hate to lose them. I would be heart broken.

Christian

Gas heat is the only way to go.

200! That is a tremendous investment of time and money. I understand, have had my koi for three summers now and would be very sorry to lose any, but especially the older, larger ones.

I used a 1500-watt electric convection heater with automatic frost setting. Dual elements, so it would run one or both, based on the need, and an auxiliary fan that would come on if needed.

Solar pool cover - Yes, I used a clear one; had a good-sized piece left over so cut thick strips and hung them, overlapping, inside the door reaching almost to the floor for a little additional insulation there.

1" thick, foil-faced foam board - inside, on the north wall and the north one-third of the east and west walls.

Thermal mass - several containers of water, from large totes to 1-gallon milk jugs.

Critter and draft barriers along the foundation - running along the 2x10 treated lumber foundation and under the gravel, I place first a wide strip of hardware cloth, then foil-faced bubblewrap.

Weatherstripping/Caulk - used self-adhesive foam weatherstripping on the panels and sealed gaps in the frame with caulk.

Backup heat - was not needed last winter, but we have on hand a small Coleman catalytic heater that fits right onto a one-pound propane tank and will keep frost at bay for several hours. Of course, have the propane tank handy, too.

Thermo-hygrometer - a wireless remote unit; sensor in the greenhouse, base unit in the kitchen.

This winter I'd really like to add a freeze alarm, just balk at having to pay so much for something that will call me on the phone when all I really need is something that will make a loud, jarring noise inside if the temperature falls below a certain point out there ... should probably ask my electronically-gifted husband or son to build something for me. With your investment, you'd probably want to invest in something that could reach you at home or away.

As orchiddude said, gas heat is probably your most reliable option ... depends on whether you have that option and want to exercise it. My greenhouse is a good 75 feet or more from my house; I don't want to run a gas line out there and, frankly, propane scares me. (I'm now probably going to hear from several corners about how much more dangerous electricity is, but it's just one of my personal hang-ups, particularly since I've seen two severe accidents involving propane. There is a GFI on the greenhouse line.)

Do you have your greenhouse yet? Please let us know how things are going.

Diane

I grow mine year round in a HFGH. I use bubble wrap as insulation. I use 2 1500 watt electric heaters and I keep a propane unit as a backup in case of a power outage. I love mine! And I discovered how trully resiliant orchids are. it can get quite cold in there in winter...down to 40 or so and the orchids never turn a hair. heat in summer is also a problem...I've had temps in the 100 degree range....and the orchids did just fine. The only plants I can't seem to grow are phalaenopsis, but everything else a 'go'! Remember that the temps quoted in most books are ideals but not the absolute that they're made out to be. One thing I will caution about is the sun and burning....you'll definitely have to come up with a shading system for your house during the spring, summer, and fall. I burned quite a few leaves the first year.

Best of luck and let us all know how you like it.

Dave
Milwaukee....zone 5ish

Thank you all for your responses. To say I have a few grand invested into orchids would be accurate.

Dave, what are you growing in your HFGH? I focus on paphs but I also have masdies, oncidums, a hefty bulbo collection and a bunch of mini and compact catts. You didn't use a solar cover?

Phals hate the cold. They really need about 80 degrees to do their best. They truly like it hot. They will grow inside the house at 65 or so but if you want to see them shoot off like weeds give them 80 degrees.

Thanks all....

Christian

HI Christian;

I grow cats mostly...but a little bit of everything. I love the 'cool' dendrobiums which I could never bloom in the house. Paphs also. As many species as I can cram in there. :) I don't care much for phals so it's no loss that they don't do well in the greenhouse. Ditto on the hot dendrobes. The temps that I described were a little scary at first but once I saw that there was no damage and the plants continued to grow unimpeded it was no big deal. Just remember...shade it till late fall. I had many problems with burning. To shade I use wooden laths available at any Home improvement store laid vertically on the roof. I can add or subtract laths to suit my needs and wind is not usually a problem. I never bought a solar pool cover as my greenhouse is actually 2 kits bolted together. It seemed to be more trouble adding it in the fall and removing it than I could handle on my own.

Dave
Milwaukee zone 5...ish

Put a few tonnes of water in your greenhouse and you won't need a freeze alarm.

Would a few tons of water fit in a 6x8 greenhouse ... and still leave room for plants?

I believe you, but I'd still feel more secure with a freeze alarm, and I'll bet my guys could put something together for just a few dollars.

I had lots of water in there last winter, no idea how much it weighed, though, lol. I'll do the math and see if it's a realistic goal for the coming winter.

... and we DO listen! (grin) Thank you, and please keep the ideas coming.

Diane

I'm in zone 4 central NY.

I only put my orchids in the greenhouse in the summer, and the masdies and other cooler growing ones don't do that well. I try to keep it cool, and put them on the floor, even so, they suffer the most.
This summer I actually forgot to water everyday a few times, and I have more in bloom right now than ever!

I even have a papillo that I've waited 2 years to bloom finally produce a spike and the bloom is opening now!

My gh is not insulated and I don't want to chance my orchids freezing, so I bring them in for the winter.

M