I have purchased a new 10x12 Harbor Frieght greenhouse. I have watched many videos about basic structure repair to beef it up. I have figured out what I will do when spring comes. I am looking for any tips on the frame and base to make it secure. Any heating tips and etc. is appreciated.

zac- I've been quite satisfied with the oil-filled heater for my mild climate (Zone 8), and yours should be even better. It has two settings (750 W and 1500 W) and I have it on the 750 W setting with the thermostat at about 40F. Even though I've only got single pane glazing, the greenhouse is tight and the heater is able to maintain that temperature even on the low setting. As a safety precaution, I have a wireless thermometer that transmits to the house so I can check that the temperature is where I want it without having to go out with a flashlight at midnight! I also have an inexpensive, unvented, backup propane heater in case of an extended power outage (though I've never needed it). One other thought: a standard 15 amp circuit will trip at about 1800 W, so, if you run an electric heater at 1500 W and have other electrical stuff on that circuit, you could trip a breaker and lose power to the heater without possibly realizing it. seamommy- To lay my pavers, I actually excavated about 8" below finished floor height, then put in 4" of gravel and compacted it by hand, 2" of sand and compacted it by hand, and then laid in the 2" thick pavers and swept sand between the joints to lock them in. My perimeter foundation is about 2' deep (so that it's just below our frost line), and it's about a foot above grade. The advantage of a raised perimeter is that it effectively gives you more headroom. The process for doing the perimeter involved excavating down, and then putting in a 16" wide by 4" thick base (with a little rebar thrown in). Then I laid my courses of cinder block on top of the concrete base. When that was done, I dropped in some short pieces of rebar in the top holes and filled the voids with a soupy concrete mix to lock it all together. I then mortared on a decorative top course of colored concrete pavers and set my frame on that. The frame is set on caulking to keep out drafts, and is also bolted to the foundation. I also attached 1" thick styrofoam to the outside of the foundation to cut down on heat loss through the foundation. Here is what it looked like when I was almost done: I didn't put weed barrier in and haven't had any problems. Because I excavated for the perimeter foundation and excavated to prepare the floor, there wasn't any noticeable vegetation left under the footprint of the greenhouse, and nothing, including my blackberry vines, has returned in the 3 years I've had the greenhouse. The only slight problem I've had was last year when some ants started excavating sand out of the floor to make tunnels and I had to zap them with the little bait cans. If you are concerned about something growing back under a paver floor, barrier fabric would likely be a good insurance policy. If you went with an entirely poured perimeter foundation, that would work fine, too. I just didn't want to have to build forms and pay the minimum for the cement truck and pumper to come in. I managed fine with my little cement mixer for the concrete I did need and the mortar is easy to mix in a bucket. Good luck.

I have a 9x12 greenhouse. It is attached to our home where a Bilko door would normally go over the outside basement steps. I just want to keep things from freezing. I have tender pond plants in tubs in it. I have double glazing, it is the fiberglass sheets that are double layer with "I-beam" construction. The ends of the fiberlass sort of look like corrugated cardboard. I used normal house windows that I got cheap and aluminum storm windows. I heat it with an electric shop heater or garage heater. They mount on the ceiling or a wall. Mine from Lowes has a light built in so you can tell when heater is on. I installed a normal home electric heat thermostat that switches the outlet where the shop heater is plugged in. In extremely cold weather I also use kerosene heater. You could use your propane heater and back it up with electric and an audible alarm that comes on when the electric heat comes on or just look out to see if the light on the heater is on. When I built the green house I dug the foundation 2' deep. Then I laid a concrete block foundation. I used solid blocks on the bottom and then regular blocks on that. I didn't use any mortar below grade thinking that I wanted moisture to be able to flow. I placed the block against each other. I had a watering system and was trying to let the moisture that went down on the ground escape easily. When I dug the foundation, I got enough stone that I was able to make the above ground part of the foundation out of mortar and stone. There is not a single crack in the mortar despite the fact there is no mortar below grade and I built it over 30 years ago. The most important part of a green house is ventilation and cooling. They will cook anything. I have an air-conditioning thermostat to control a vent fan. The vent fan is for a barn and has louvers that automatically open when it is on and close when it is off. Mine draws air from the basement when the fan goes on. Yours would need some source of air like another louvered vent.

You can save a considerable amount of energy in the greenhouse with a few simple steps. 1) Insulate the greenhouse foundation (See Foundation FAQ). 2) Insulate the north wall and north roof. Little light comes through the north wall of a greenhouse in the northern hemisphere, so insulation of this wall helps with energy losses without sacrificing any sunlight. One approach is to install foil-backed foamboard insulation, with the foil side facing into the greenhouse. 3) Seal off vents, weatherstrip doors, and caulk or otherwise close off other areas of air infiltration. 4) Double up on glazing. A double or triple layer of glazing can be added with an additional layer of polyethylene or with the addition of "bubble wrap." 5) Add thermal mass to the greenhouse (See FAQ on thermal mass). Information provided by: Stressbaby