Good day. I'm a greenhouse manager and I have a few thoughts that you might consider in building a greenhouse. 1. Plastic vs. Glass Double-poly is much better for heat retention (higher R value) but transmits less light than glass. Poly does not last as long, but is much less expensive to set up. Generally, unless you are building a GH (greenhouse) for commercial practices, the savings from building plastic are probably worth it, especially in a climate where you want to heat. 2. Carbon Dioxide (CO2) Generally the bottle-neck of photosynthesis is CO2. In the general atmosphere there are about 340 ppm. In a greenhouse, the plants tend to use CO2 quickly as they grow and so the CO2 ppm (parts per million) drop. One way to solve this is to vent a lot of the time to keep the ppm closer to the ambient levels you would find in your garden. A commercial greenhouse would increase the ppm to 800 or 1000 ppm (maybe higher depending on the crop) and get about a 50% increase in photosynthesis. If they are venting a lot, however, they may only try to maintain 500 ppm, because it's a cost to add CO2. You might look into a CO2 generator that runs on natural gas. They are not terribly expensive (although I have no idea what budget you are working with) and could give you a 50% increase in photosynthesis (and, thus growth). 3. Moisture Regulating humidity levels is tricky, and if you're not around a lot can be a problem. This is especially true in a soil floor GH. In the GH, the relative humidity will climb, especially at night, leading to problems of botrytis and other diseases much more easily than would affect a garden plant. (This is one of many reasons that almost no professional greenhouses leave exposed soil in their GH, though there are some old school places and a few types of cut flower production still done in the soil where exposed soil is necessary.) Commercial greenhouses use computers to keep the RH (relative humidity) regulated, generally below 86% depending on crop, since many serious diseases require environmental conditions slightly above this to germinate. If you really have to grow in soil, you might consider using plastic mulch and planting the pumpkins in the holes in the plastic sheets. This would minimize the exposed soil, and help keep your RH more in control. You also really should get Horizontal Airflow Fans (HAF). Install them so that there is a continuous circulation of air above the crop. This keeps pockets of higher moisture from accumulating around the plants and significantly decreases diseases, aside from a number of other benefits. 4. Pests There are a number of pests that are more likely to infest a GH crop than a garden crop. The conditions are particularly perfect for certain insects. It means that it is well worth your while to learn to identify them, and watch your crop more carefully than you would a garden crop. You might want to put in yellow sticky cards and keep track of how many insects of various types are trapped on it. There are a lot of good biological insect controls available that are more useful inside an enclosed space than outdoors. If you know what insects are affecting your plants and in what quantity, you can use these biologicals and avoid spraying (in Canada, almost no commercial vegetable greenhouse sprays biologicals are almost exclusively used. This is a change in the industry in the last five years.) Having an open floor also means that some insects, such as thrips, are more able to breed. (Another reason to cover it, in my opinion). 5. Watering The greenhouse gets hotter easier and plants dry out more quickly. But timing of irrigation is important because the moisture from irrigating is more likely to affect your RH negatively. Be more careful of when you irrigate (try to avoid it at night even more so than in your garden). Anyway, I've rambled long enough. Good luck with it all.

Ok Thanks to all and the constructive criticism I really have a thick skin and can take it!! I will try to address all concerns addressed so that others and myself can benefit from my mistakes made . "I am more concern about the structural concept. If there is not enough cross bracing, any small movement due to foundation shifting or wind load can pop the glass panels out and do some serious damage to occupants. " The building was built like any other normal building frame style. Everything is built then the glass is added and capped for finish. After that its all sealed so any water cant get thru. On the north wall there is a 24inch section of plywood from the floor up for extra strength. Combine that with the plywood gables there is no movement at all. Its built like a brick you know what before the glass goes in. "There is not a lot of detail in the photos for comments. I can see the sheet metal cladding on the wood. I am not sure that¡¦s a good idea. Have a vapor barrier on the cold side of a humid environment can be problematic." Just ask Ill gladly get you more pictures of any detail you request. The aluminum on the wood is just to keep the water away from the wood and clean up the appearance. I donÂt heat the GH in the winter. Its used more as a storage shed in the off season. All vents are left open and the screen door is also left open to disperse any heat in the winter months. "overall, the design does look impressive and admittedly, I was being overly hard on it. But, recheck your calcs for "structural" glass construction. ;) BTW, If you're still interested in exploring a post + beam framed greenhouse, I've designed quite a few timber framed buildings - many with attached passive solar sunspaces utilizing true post+beam joinery and patio door glass panels, in both vertical and sloped glazing applications. Email me if you'd like to see completed project photos and perhaps share some details." I appreciate the honesty it actually helps me learn. I would also love some help on the "calcs" of the glass install it self. Is the Half inch flange of metal not enough in your opinion? Remember the kerf deal is long gone. The aluminum acts as a kind of glazing strip..Please by all means advise of any other way that may help others reading this.! On the roof itself the glass lays flat on the wood surface with a 1 inch space in between glass panels (lots o silicone). I then screw a 1x3 in between the glass sections so the wood overlaps the glass.At the top of the roof there is about 8 inches of plywood sheeting due to the fact the glass wasnt long enough. So I made the glass start from the eves up as opposed from the top down.I honestly think I gained major strengh this way I then cap over wood for apearance only on the roof. I would also love to review any post+beam joinery and patio door glass panels, in both vertical and sloped glazing applications now your talking!! This is something that I have always wanted to figure out. the next house perhaps!! Let me know what you have in mind.

plantslayer- I don't know if Gurney's has the offer online or only through their catalog, or if they will repeat it. The advantage of the tunLCover is being double-walled. They are not very big. They are also very easy to move around, and I use them where I want to plant to dry out the soil a couple of weeks in advance, as rain can't get under them. I start seeds indoors. I hang 2 4' fluorescent fixtures on the undersides of the upper 2 of 3 tiered metal shelves, 2 levels of grow area. The 10x20" black plastic flats for starting seeds just barely fit across, 2 per shelf, = 4 flats. I have some special rose pots that are 2 1/4" square and fit 36 to a flat = 4 x 36 = 144 seedlings. I got so carried away this year because of doing a new seed sprouting method that proved too successful, starting seeds on damp paper towel inside small ziplock bags from Michael's. Cucumber seeds that hadn't come up for me for several years that I considered dead had near 100% germination- I foolishly started ALL of three packs of seeds. I also tried a bunch of really old tomato seeds I wanted to clear out. I had to add 7 flats to deal with all the seedlings. I used all my other indoor shelves temporarily plus made some. I started cukes and squash 4/3, planted out under tunnels 5/8 and 5/16, started picking cukes 7/11 and squash 7/23. It is amazing how fast squash grow under the tunnels. Unfortunately, I also tried tunnels over pea and fava bean seedlings, in an area I had grown pole beans for a couple of years. I guess it had built up a big vole population. I pulled up the tunnels to check on germination and the ground was just churned with vole tunnels going up and down the entire bed, only about 3 peas managed to come up. I tried setting mouse and rat traps, caught a few then none. Maybe the used traps smell bad. The strange part was that the things I caught didn't look like the voles I've seen, they looked more like an Old World mouse or baby rat. I still haven't figured that one out. I did manage to finally plant some pole beans there, I just made small holes for the seeds, dumped cayenne pepper on them, and put a 4" galvanized nail in by each seed. Gardening can be such a lot of work. Some of the beans are nearing the top of the trellis. I hope they make it. OTOH my runner bean experiment in an area not used for vegetables before had 100% germination and hit the top of the trellis a couple of weeks ago, and is yielding beans already. I think I've really "bean" overlooking runner beans, in favor of regular pole beans, but runner beans may be a lot better adapted to our cool nights and summers. I tend to wait too long to pick but have been making myself pick them rather small and they have been tender, and taste good. They beat out Contender, my fav early bush bean, by a few days. Nancy Here is a link that might be useful: TunLCover photo

Ann, your description of a gardener cracked me up. It describes me to a "T". At one time I pined for a greenhouse, skydiving and hot air balloon rides among other things. The urge for skydiving has passed ( a DD-in-law broke her ankle and knee doing it and now has a few metal plates but mostly the change of heart is due to advancing age) but a balloon ride and a greenhouse...sign me up! Cath