BTW, my plan is for a 8 foot high sidewall, peaking to 10 foot in the middle.

Just my two cents here and please take the following as nothing more than that. This sounds like a lot of work for just putting out bananas. I also believe it is going to cost a bit more than you expect...especially when it comes time to heat it. You know how cold our winters can get. You may only buy yourself enough of an increase in temp to keep the plants stable. Even with soil heating cables throughout, without some sort of permanent foundation, I don't believe you would be able to keep the soil warm enough without it freezing or near freezing below the cables. That cold is going to leech out and make it even more difficult to heat. And remember the old saying for greenhouses...it is harder to heat a smaller structure than a larger one. It also sounds like a lot of work doing this every October and taking it down in the spring.

Why not look into using the money and do a more permanent and larger structure? I know the initial outlay of funds will be greater. I do believe you will not only be money ahead in the long run, but much much more satisfied with what you have rather than something temporary. You would also be able to house all of your tropicals as well. I honestly think you will spend a lot of money on this temporary structure and end up hating it and the whole process before your first year is up.

You live in Columbus...you are more than welcomed to stop by and check out my setup for ideas and such. I will gladly share the goods and the bads of greenhousing! Right now I'm going thru the "bads"!

Thanks for the advice. First I want to say, yes I'm that crazy, lol. I spent about $1500 on growing these indoors in pots, and have experienced success. This year though, due to several different issues non-related to growing them, i let them go dormant and lost the stalks. I also grow Palms, and would create a nice little raised garden area around where I would build the greenhouse.

I've priced the materials (19k BTU heater included) to be roughly $900-$1000. For the size and temp I want to maintain, the heater should be 13k BTU, so I've built in some safety. It's gonna be electric, and I'm calculating monthly costs of about $100 in heating. I'm just not sure how the ground would react, if the air temp inside the greenhouse is 75 degrees. I would assume that with heating cables around the perimeter, the ground would be relatively warm, not to mention the raised beds.

Buckeye,

This advice is from a Wolverine, but one who has grown GH bananas like ohiojay.

I have grown Dwarf Red, Dwarf Namwah, DC, and a few others, and I keep my GH 55F. They are in the ground and I don't use heat cables. They won't need 75F.

I don't think your problem is going to be warmth. Your problem is going to be cooling. It is the days like we're going to have next week, when it is pushing 60F in February that you need to worry about. In these instances, the temp will rise dangerously fast and you need to ventilate the thing. And smaller greenhouses are more susceptible to these temp fluctuations than are larger houses.

Do you happen to have any pictures of your greenhouse? I want to see if it looks like what I'm looking at. What type of materials did you use, and whats your monthly running cost?

Click "My Page" next to my name, I have a few pics there. More below.

Not sure what my costs are because I heat with propane from the same tank as the house. It ain't cheap to keep 55F when it's -10F though.

Here is a link that might be useful: Photobucket link