Hi Jeff, I am in a similar situation. I have mangos, bananas, guavas, citrus, papaya, carambola, lychee, pitomba, pitanga, grumichama, gardenias, plumies, adeniums, etc, etc. 1. Anyone in similar circumstances? What GH did you get, and are you happy with it? For various reasons, my GH is 20x23 tempered glass. I really like it, but at times I wish I had twinwall PC...better insulation and wetfeet is right, better light diffusion. 2. I'll probably use electric heat, but what do you use if the power goes out? Are there gas/propane heaters that can kick on in that situation? You can rig a backup generator. Alternatively, you can use backup gas/propane, but you probably would either have to have them on a microvoltage thermostat with a pilot light, or you would have to fire it up on your own. The next question is whether to use a vented or unvented heater. Vented heaters will not cause any plant trouble, but unvented heaters might. For a raging debate on this issue, look back about 6 months in this forum (or just wait until it comes up again this next winter). I have tons (literally) of soil and rock which act as thermal mass, but I don't go out of my way to add barrels of water. I'd rather fill the space with plants, and my experience and experiments tell me that it doesn't make that much difference anyway. Email me if you want details. 3. Can you grow tomatoes, peppers, herbs? Sure. Peppers and herbs are easy. Tomatoes are harder...they like a lot of light and heat, they take up space, they attract whitefiles like crazy...for me, they don't produce well enough to make it worth the space in the winter GH. 4. I've read that ventilation is important, but do you really suck icy cold air into your GH? No. The way I do it, and the way many others do it, is to just use passive ventilation in the winter. So rather than having a fan drawing air through, you just have a roof or ridge vent open to let a little heat out. Minimizing infiltration is important, but you will want some winter ventilation to keep humidity down. Venting and reheating is an important method of controlling the VPD. When you get rolling, let's trade some plants! SB

Are you planning to grow enough veggies for four people over the winter in a GH? I'm in zone 6 and unless you add expensive lights, most veggies just "sit there" during the short days of winter. They produce nothing! You'd be better off gardening outdoors all during the warm months and either canning or freezing your harvest for winter meals. That's just my opinion. Others may disagree.

What would you like to grow? That is the question that you should ask yourself first. Why do you want a greenhouse? In my own personal situation I built a structure to use for 2-3 months a year (mid Feb to mid May) in order to grow seeds to transplant into the ground to make some use of the 5 acres of land I have. June to the end of September there is nothing in it at all except me when it is raining but I feel the need to be outside. However! during the winter then I use my garden structure the most. There are no plants in there, but I get wrapped up in all my outdoor survival gear and walk through snowdrifts and blizzards 200ft to a tropical paradise! Even when it is below freezing outside with a clear sky it gets way above 80F in my coldframe in the day. An extension cord provides the power for the coffee maker, power tools and the laptop. It is way warmer in there than in the house! A great workshop. A place to re-build mower and tiller engines in the warm with lots of light and no heating costs. This winter one area is going to be set up with the equipment to make glass beads. To get back to your question, then why do you want a greenhouse? Side note to everyone else.... when you don't have plants in your greenhouse, and all that wet stuff too, it does not rain in there in the mornings!!!! (condensation dripping)

you need to get some proper hydroponics fertilizer. That miracle grow stuff is not adequate. You need a bunch of shade cloth to drap over the greenhouse in the summer time to help keep those temps down. The shade cloth won't be enough so you will have to do something else. Out here where we don't have humidity, large evaporative coolers are used. I don't know how well they will work out there. You will probably also need to use a misting system to control heat and you'll want to run that off of Reverse Osmosis or, since you seem to have a bunch of it, rainwater. You could bury the rainwater reservoirs being used for the misters to more effectively cool the air. As you have already discovered, you need quite a bit of air circulation inside the greenhouse, I would get more though. Until you get those control systems built and some experience with the systems you already have, I wouldn't build that A frame.