Kristi,
I've been following your posts about your greenhouse with interest because I put my little pop-up greenhouse up here in Dallas this year as an experiment. We had 7 degrees last night, and even with the propane heater in there, it went down to 33.5. Now, the propane heater was set on low - because it was not supposed to get that cold - so tonight it will have to be set on Med. It has stood up to windgusts of 40-50 mph without flinching, but the heating remains my problem. Haven't moved any amaryllis out there because I haven't figured out how to keep it above 50 all the time. The Brugmansia are tolerating it. The begonias, and petunias are blooming like mad.
How are you heating yours? You are much further south than we are but I'd really love to figure out how to use this little thing for my amaryllis. How much propane are you going through? Thanks.
Julie

I don't have a propane heater, it's a small electric heater from International Greenhouse Supply. It keeps them nice and warm at 45!I should get a little propane heater, just in case of power outages.

Can you tell me what kind of heater you have? Is it something I could buy at Sears Hardware or Ace??
Kristi

I got mine at Tractor Supply. It is a MR. HEATER BIG BUDDY portable indoor safe propane heater. It can run off little 1 lb canisters or you can hook it to a 20lb tank with a special hose connection. It puts our 4000 BTU on low, 9000 on Med, 18000 on high. The chart I found on the internet said I needed 10,000 to 15000 BTU heating capacity to handle our coldest weather given the size and low insulation of the pop-up. I figured that it would be handy to have around the house, in case I needed to heat the garage, barn, or even the house for an emergency.

We went decades without any really cold weather. But that has changed in the last 2 years and the area is back to the kind of weather it had 40 years ago. Being much further south, you could probably get by with a smaller heater.

http://www.littlegreenhouse.com/heat-calc.shtml
That is the link to the calculator we found on-line.

I don't know about pop up greenhouses but I have a 6x8 harbor freight gh and it was only 250 bucks. Best investment ever as far as in concerned. It's sturdy and insulated. I'm in Dallas too this super cold weather is killing me. I usually just have a 1500 btu electric heater out there and works just fine but I has to drag another small heater out there recently and it's staying comfortably in the 60s. Then again when the power went out for 8 hours today they didn't do much good but were back in business now. Power outages on the coldest day of the year, good to know you can count on oncor. Now I have a back up propane heater and I always will. Just thought I would share. Good luck with the cold.

Thanks for the info. My husband and I have been talking about building me a little gh so I thought I'd play with the pop-up so I would get some idea of what I need when we are making plans. What are the walls of your GH in Dallas made of?
Thanks,
Julie

Believe me folks! You MUST have a back up propane heater if you value your collection and the power EVER goes off during cold weather! If you don't, take those plants inside the house until it warms back up and the power is back on. I am still dealing with the consequences of my power outage AND propane outage back in late Nov. And a warning on greenhouses...at least here thy really slow down the growth in winter compared with the house. It is much cooler and damper in the greenhouse and where some plants like it just fine, the humidity level is a bit high for my bulbs. THey do like the additional natural light though. As you mostly know, I grow amaryllis through winter for my cut flower business, and the ones I usually have at Valentines Day (We open special for this then close again until the daffodils start), are going to maybe be in bloom with the daffodils this year. I think I am moving them to my work room this week. The lighting is mostly artificial there but I can keep it at 65, instead of the night temps in the upper 40's in the greenhouse. At the moment my greenhouse thermometer says it is 60 (9 AM) but our weather modulated over night and will be in the upper 40's to low 50's today.

Yesterday I pulled the plug out of the lower cold air intake that was opening when temperatures rise in the sunshine then sticking open. Will talk to the dealer about this if they are at the Northwest garden Show in 2 weeks. (I hate phone calls!)

Last night got a much larger snow than predicted - around 6 inches. When I went out this morning, the greenhouse had collapsed. The center of the roof had caved in - snapping 3 of the fiberglass poles that hold it up. The temp never dropped below freezing because the heaters kept running and the plastic skin never tore. Have patched it up with splints and gorilla tape and put a new center pole braced in the ground to support the roof line in the middle where it is weakest. My advice to anyone who wants to try a pop-up greenhouse in an area far enough north to have snow and ice is to put in a center pole before the dammage is done. Live and learn.

My greenhouse has been holding up well, in spite of being covered with ice. No snow... :-(

I am going to get a propane back up heater tomorrow, as we are supposed get more subfreezing temps next week.

Thanks for all the discussion! Some day I'll have a real greenhouse...with 8mm double walled polycarbonate, etc!!
:-)
Kristi

Everyone, I can not suggest enough to people on a tight budget the Harbor Freight GH. Go over to the GH forum there are lots of threads about them. For 250 bucks or so you can have a nice aluminum framed double walled poly GH. I have had my 6x8 for 2 years now and it has held up wonderfully. It holds heat great and is super sturdy. Ive hit my head on the doorway enough times to know how sturdy it is. Sign up for harbor freights email list and you will get coupons galore sometimes ones specifically for their greenhouses. They even have bigger ones that are still really reasonable. Wait for a coupon though! They always send them out. Anyways I am not a salesman for them, I just am a really happy customer. Kristi I think one would work great for you im only a half zone north of you and the cold is no problem. Its a nice 70 degrees in there as we speak.

Bloomingcelery, that is what happened to my 10'by10' pop up "FLowerhouse. Except that we had a strong wind too that dumped loads of heavy snow from the trees onto it and the poles splintered in the wind. The plastic cords also snapped. THey withstand rain and wind fine but the heavy snow load did them in!

After two of these pop ups had been damaged by weather in a few years my husband decided it was cheaper to buy a real greenhouse. It wasn't :-), but what I have now, the SunGlo was designed for heavy snow loads.

One other bit of greenhouse Info I Am glad I picked up from the greenhouse forum...if you get a real greenhouse, and are over about 5' tall, put it up on a knee wall! You will then have room for hanging pots as well as 2 layers of shelves and, and no claustrophobia! My knee wall is 12" of cement, and I have a poured in place floor with 2 drains and that was well worth the hired contractor! My greenhouse is 8' by 18'....and no, there is no such thing as "Big enough"! We were able to order the door extension panel to match our kneewall additonal height. They just make a door width piece the height you added and that brings the door down where you want it. It was an easy adjustment.

Great suggestions! Thanks. My husband is sold on the idea of a hard sided greenhouse. Now it's just a matter of when.

I have plans to build a "real" greenhouse soon enough, but this one is serving the purpose. It was $199 with free shipping and at the time I wasn't looking for a permanent GH...need to have the backyard re-done and will find the perfect spot for one then.

In the meanwhile, I've ordered my buddy heater and it came in today. Got 2 small propane bottles so that should carry me over for at least 12 hours, which will give me time to get a bigger propane tank (120 hours), etc.
Kristi

Kristi,
Propane on low last night kept the GH at 51, outside it was 15.

Speaking of the perfect place in the garden for a GH, if you come across something that explains how to orient the GH to help it stay cooler in summer and warmer in winter - here in TX - let me know. Did not find anything like that on the GH forum.
Thanks,
Julie

My greenhouse company suggested planting a deciduous tree in front of it, but I haven't done that yet. I don't want to shade out my sunniest spot! I think I will go the shade cloth route.