Samantha left a comment this morning and my reply was a bit long for the comment box...
I'm building a 'hot house, with wood and plastic, to extend the seasons, somewhere in January probably. I'm not sure it will work, but I can try.'I'm just not sure about one thing, and thought maybe you knew. The plastic covers the front and all sides, but the sides will be 'flaps' which I can open when it gets too hot. However, I can choose to leave about 5 centimetres at the bottom free, so it all has room to breath. But will that take out all the heat? Do I need to close it up completely for it to work, or can there be a small gap at the bottom?
Samantha (who's a bit confused on this area (airflow or loose of warmth???))
Hi Samantha just a few points first:
That hot house we made recently was only temporary and not for a full season of growing.
If you intend to use one to grow food (or anything else) over winter you might need to heat it in some way.
It would probably be best to make it seal at night to keep any heat in. The flap idea sounds good for warm days...keep a thermometer inside (a min/max type is good) to see just how hot it is getting inside.
I keep containers of water in the hot house to hold some of the heat at night as I don't use any extra heating in it/them.
Your area would probably get colder than mine so heating and sealing it at night would be important.
I'll include some links you might find helpful to you and others who live in the North (world ).
The first is to the It's Not Easy Being Green forum discussion about a "heat sink" to use in a green house. UK.
This link has a lot of links about green house management in general that could be of help to you.
The University of Alaska links page...they should know a bit about Hot Houses up there!
I hope those links will help answer your questions!