Saw this DIY GH project and thought some of you might be interested in it. I have one of my old wooden grow boxes and the wood is falling apart and the greenhouse covers need to be replaced just about even year, so this project looks interesting for next year. Here is a link to it:
That’s a nice solid build for that size of a structure. 
I’ve been looking at many different plans from builds starting from scratch or kits.
I agree, I would build the interior different, not so many shelfs and not make it as tall but other than that, I like the way it was built. You can buy one like it from Harbor freight but the cost is more but you have to put it together yourself and instead of the corrugated clear fiberglass, they use individual double sided panels. I’ll see if I can find a link to it, if you are interested?
Here is a link to the HF green house:
10 ft. x 12 ft. Greenhouse with 4 Vents
Here is a smaller one, this might be more to the size I’m looking for:
Unfortunately, I have to hold off from getting one with the projects in home going on.
That seems like a little over kill to me, but it would be very solid that’s for sure… I have one of the Harbor Freight 6x8’ ones and it’s pretty nice, it is a little frail compared to the 2x4 model, but it has worked for me… Only issue I have had is without adding heat at night stuff freezes in there and the worst issue is you need to be watching during the day to get it opened up so it doesn’t get too hot and kill all your plants… Once I got the high tunnel I haven’t used the GH much, since HT can be managed a little easier while I’m still away from home working.. I really would like to have more time to use the GH, it could really help my spring starting of plants, but for now, Rudy’s in Logan is doing that for me… and I’m getting better quality starts… When I’m retired I may try again, but for now I just don’t have the time to give it the attention it needs. After a couple weeks planted out in the HT, some of my tomatoes are really starting to look good, seen a bunch of blooms last night, so maybe I’ll have tomatoes by the “Forth of July”…
That is the variety I plant for my early maters… Also have some Big Beef starting to bloom, been a slow scary start this year with all the late frosts, but hopefully it’s time to grow now… Later J
The more expensive models from HF have temp controlled vents in the top and once the inside temps reach a certain temp, the vents automatically opens. The other issue you mentioned was them freezing, you could always put one of those small heaters in there, like the ones you use in your ice fishing tent, during the Winter.
True deal on both, just haven’t been that motivated to do it… On the vents, I’m not sure roof vents would be enough, I typically had to leave the door open as well… J
JJannie is the member that has that type of HF greenhouse and I think you are right, when its really hot, I believe Jil said they had to leave the door open as well.
I have been amazed at how much heat a greenhouse creates, even during the cold months… If the sun is shining, it really heats things up inside… Do you think we are past frost for the year yet? I’m really not trusting this year even though we are past memorial day I still don’t feel like I’m safe yet… Hope we are… Later J
My best guess is yes, we are done with the frost but that being said, I remember a late snow we got many years ago, that came in June.