Building a Greenhouse - Questions

1. Generally speaking, greenhouses are heated by trapping the solar energy that comes from the sun. This warms the air, the plants, and the floor of the structure. It retains this heat because the primary source of heat loss is convection (air movement), which a greenhouse restricts. Have you ever tried building a solar cooker? We use a solar cooker in the summertime to BBQ in the summertime, and we've managed to get water to boil in an enclosed solar cooker at -35 degrees in winter. 🙂 Stone is a good heat retainer, as is standing water with a dark bottom.
2. There are quite a few online manuals on building greenhouses, but it can easily be done with glass/acrylic/plastictarp, some run of the mill aluminum extrusion (80-20 brand, or other).
3. Plastic is the most flexible or versatile as a solar absorber, not not the most structurally sound. If you have the cash, go for glass or pick up some second-hand windows that can be framed into a 2x4 wood structure, especially if your location is prone to severe winds/storms.

A few references:
http://www.albertahomegardening.com/how-to-build-an-inexpensive-hoop-style-greenhouse/
http://www.amazon.ca/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=building+greenhouse

Greenhouses can extend your growing season so you have more time to plant and harvest.

Even unheated they will keep the elements away from the plants, so no over watering when it rains!

If you have firewood then a rocket stove could be used to heat the inside efficiently and many people have done this. It is a DIY project.

Plastic will break down in a year or two depending on how fierce your sun is, Acrylic is usually good for 10 years before yellowing and Polycarbonate is expensive but has better thermal insulating if you want to go double walled. Glass lets the most light through and will last forever (unless you have lots of storms/hail.)

Permies.com has lots of info, also, how do you feel about growing fish in your greenhouse, either for eating or looking at? It can be done and water stores heat so if you have a large thermal mass such as water you can help cool the green house in Summer and keep it warm in winter. If this is something you might be interested in head to one of the aquaponic websites, Practical Aquaponics and Backyard Aquaponics are great, once again, a DIY project but many people are experimenting and the hard work has been done.

I would be going with waist high gardening because I don't like bending down or weeding but your personal circumstances and goals are what are going to drive this project.

Good luck and post lots of pictures!

Thanks for the intel. Lots to consider and think about. I am starting my planning now

while true normal poly will degrade in a few years
(shorter in hail, wind storms etc.)
there is a company in manitoba that makes a far superior poly-type product
http://www.northerngreenhouse.com/about_us.htm

also consider whether you want to have in-ground beds or above ground
if in-ground think about rigid insulation sheets in an 'L' shape around the perimeter (18" deep),
before you build the framing
this will greatly improve critical heat retention in spring/fall

heating is energy intensive,
but as mentioned a rocket stove is efficient,
especially if you have access to free wood

another option is to dig down 3'-4'
insulate the walls, and build raised beds about 12" below ground level

I've been watching videos by Eliot Coleman on Youtube for the past few days. here's a great one for some ideas on building your own greenhouse. It doesn't go into extensive detail but it does give some very handy tips...

http://www.youtube.com/watch?v=ovR-OZlul3w

Any video by Eliot Coleman is worth watching. I also have his book The Winter Harvest Handbook which I highly recommend.

If threestorms lives in Alberta, he/she will see all weather in the summer months. I too am looking into building a small greenhouse. I've only lived in Alberta for about 7 years, but since living here, I've seen hail storms every summer. One was so bad that I had to file an insurance claim on my SUV. What would best stand up to a hail storm like that?

Well, for what its worth, most of my family in alberta never built proper greenhouses like I see out here in ontario, what they would do was put on a south side facing porch, screen it in and then build pop in and pop out solid glass windows or plex windows that would go up in late fall, allowing a outdoor safe space for winter shortage, and by feb/march, it was shelves after shelves filled with starts/greens, and when the weather got hot, it would be openned for the breezes though the screens, and then closed back up to extend the season in fall.. would not work for a small house but most of my folks had a whole house side done this way, with one spot left for a small table with one or two chairs only for sitting for tea or working hobbies etc.

Because the roof and stucture was built as a large porch/covered deck it was really solid but it worked very much as a greenhouse, even to the point of my grandmother using the winter heat up in very early spring to help heat up her main floor of the house as grandpa had put a vent in that you could open and close.

Just depends on what you want that greenhouse for, if its for starts etc, this might work just as well and give you extra house space in a number of ways, but if you want a inground greenhouse, you will need to see what the companies in your local area recommend, I would think it would make a big difference on where in alberta, further north, I would think snow load would be a major worry, but down south, I would expect it to be winds that would be of high concern.

I had a small green house when I lived in Calgary. It was a piecemeal structure made of scap wood with old glass windows on three sides plywood on the N. side and that corrugated green stuff on the roof. It extended the growing season about a month on either end without being heated, although I also used water cloches for the tomatoes and cucumbers to make up for the lack of heat in the spring. Started the plants in the basement under flourescent light.

It survived the one hail storm we had, but succumbed to the neighbors pryromaniac kid with a can of bbq lighter fluid.