clvlnd- It all epends how warm you want it. I have a 10' X 15' single pane glass greenhouse in Zone 8. I heat my greenhouse with an electric, 900W/1500W oil-filled heater. It's got a thermostat and I keep it on the lowest setting so the temp stays above freezing. You can usually get a decent one for about $50 (e.g., from Amazon). If you get an electric heater that draws more than 1500W, or run more than one, you're going to blow the breaker on a standard 15 amp circuit, especially if you have anything else plugged in. If you want to use something bigger, you're going to have to seriously upgrade the wiring that supplies electricity to your GH. One of the reasons I can get by with a small heater is that I also have 3 seed-starting mats that measure 1.5' X 4', and each one only draws 100W. I just set my sensitive plants and seedlings on that and everything seems to be happy. Since I usually have a power outage a couple of times during the winter, I have a small propane heater for backup.

Usable wall space might be another consideration. The side panels of the 10x12 are 6 5" tall. With the base/foundation, our side walls are about 7 tall. This will allow a 30" tall bench, a wire shelf above that, and a lower shelf under the bench top. So, three levels of plant space is easily possible (I generally have small pots of cacti and succulents.) The side panels of the 6x8 are 4 tall. The final height is determined by the height of the foundation added, so adding a 12" foundation could mean sidewalls about 5 tall. For my plants, that might limit me to two levels of plant space. The 10x12 does allows a bit more flexibility in floor plans. WeÂre building a long bench on each wall, and adding three peninsula benches off one bench, with standing spaces in between. Somewhere I saw a pic of a 10x12 with a U-shaped bench around all three side walls, and a small island workspace in the center. Not roomy, but possible. Regarding aesthetics, I like the feel of the overhead space, but I admit the GH does "stand out" visually in the yard. A shorter GH would have blended in better with our landscaping. I like it when IÂm inside, but when IÂm outside I wish I could crank it down a few inches! At least one member here has mounted a ceiling fan at the peak of the 10x12, another use of that space. IÂve considered creating a "false ceiling" out of solar pool cover in the winter, to block off the peak and limit the amount of air IÂll be heating. (I already have three horizontal braces in place at ceiling height.) IÂve wondered if the (roughly 10 ½Â) height of my 10x12 might help it feel coolerÂif the warmest air concentrates above the level of my head and my plants? But I have no knowledge to support that idea (my newly erected GH is still one big oven.) Maybe someone else has thoughts about thatÂIÂm too new to understand how warm and cool air behaves in these things.

Hi Terri, here's a thread showing funnylady's photos of her two 10x12 HFGHs joined together: Two HFGH 10x12 Greenhouses Joined Together Also, rosepedal has joined two of them together, and there are some photos at the end of this thread showing the new one being added to the back of her existing greenhouse: We're Going Saturday rosepedal (Barb) may have posted more recent pics somewhere, and I may have missed or forgotten them (been helping my Mom get through several hospital adventures this summer, and I have fewer brain cells lately!) Here is a link to some photos that milwdave posted of his two HFGHs, joined end to end. I believe his are the 6x8 size, if I remember right. Greenhouse Construction No room to add another one on to mine, but I wish I could. Hope this helps a bit! Sheri

There are two different sizes of the rigid style greenhouse... 10'x12', and a 6'x8' model... as shown in the link below. If you're going to invest in a greenhouse, and you want something decent without spending a fortune, it would be wise to save up a bit of money and get the 10'x12' model. This is the size we have. Anything smaller is almost a waste, because there would be very little room to move around in, and you would be limited greatly in what you could grow. We waited until Harbor Freight put the larger sized model on sale, and I believe we paid somewhere around $500, if memory serves. We bought it about 4 or 5 years ago, though... and I see the price has gone up a bit. There are some modifications you're going to want to make. This is a relatively cheap kit made with cheap materials... and the directions that come with it are not really as specific as needed. However, when compared to other similar sized professional greenhouses from companies that specialize in them, this is a bargain! I would suggest investing in a concrete foundation or a knee wall to attach it firmly to. Ours was built on pressure treated lumber, and I know it isn't going to last as long as it could. It was reinforced, however, and the panels were attached with silicone all-weather sealant AND the little clips it comes with. The clips alone are not enough, and a good wind will blow the panels right out. How do I know this? I had to go searching for 3 panels after a bad storm wreaked havoc on ours. After we found all the missing panels, which had luckily survived in one piece, we used the sealant AND the clips, and redid the whole thing. By Googling Harbor Freight greenhouse or other similar keywords, or by searching with those same keywords here, at GardenWeb, you can find oodles of great information and upgraded, detailed instructions, photographs and tips from gardeners who have erected one of these kits. Ours has the 4 vents on the roof that open, the double sliding doors on one end, but it's lacking in anything else. In ours, the floor is deep pea gravel over landscape cloth, with a slight grade underneath to allow water to flow out and away. It's not plumbed for water or wired for electric... but I have an outside water hydrant nearby, and a garage close enough to run an extension cord for the fans. This is what it looked like inside earlier this year before I did anything with it. I hadn't installed the fans, and you can see the panels on the floor awaiting replacement... Here, it's a little later in spring, and I'm starting to fill it up with plant materials... Here, the fans are in, and you can see the hose on the floor... This is picture looking at the rear of the greenhouse through the front garden and fence... Here's a few plants I grow in front of it, and the little gravel walk leading up to it... This is the rose "Quadra" growing next to it... I hope this gives you an idea of size and construction, just as an example. The inner shelving was built by a carpenter friend, using lumber and fencing as the table top material. There are all kinds of gadgets you can get... automatic timed fans, drip and mist systems, you name it... ours isn't heated, but it's useful three seasons out of the year. I typically start seeds in the basement, under lights on heating mats, and I move everything out to the greenhouse as soon as possible. I keep my more personal plants and anything I'm worried about inside the greenhouse. This past year was our first using it, and I've learned a lot. I still need to learn more, but I'm on my way! For a decent greenhouse on a budget, you really can't go wrong with Harbor Freight products... as long as you do a lot of reading beforehand, and you have some help knowledgeable about general construction. Hope this helps! :-) Here is a link that might be useful: Harbor Freight Greenhouses