First assembly was a failure. The greenhouse lasted a whole 21 hours. Strong (70mph) winds demolished the aluminum framework.
We recycled all the panels and the roof structure, re-building the frame with 2x4's. Just experienced another bout of strong winds and it held it's ground!
The seedlings are all doing well. I put a small space heater in just to keep things above freezing. The tomatoes wilt over night but perk up by 9am. Snow peas are growing by leaps and bounds, broccoli and cauliflower are doing ok, not great. Peppers haven't sprouted yet. I will plant some more and keep them in the house until they sprout.