- Oct 24, 2019
- Reaction score
- mid-Michigan, USoA
All a greenhouse does is increase the temps when the sun is up.
It has close to zero insulation, but it does help with protecting plants from wind.
If you want a greenhouse to hold heat then it needs to be partly sunk into the earth, proper insulated roof and proper double pane windows.
I have seen plans where the entire greenhouse is sunk below frost level, and I have seen other plans where you have something like infloor heating in the growing beds.
There are some creative things put there.
But for zone 4, in the winter time grow stuff indoors.
the other thing to consider is ground heat storage as you can use pipes and small fans to move heat in the winter and to get cool air in the summer. look up the youtube vids on the guy who's growing citrus up north.
for winter heating if there is any sunlight you want thermal mass capturing that heat as much as possible and if you have a way of putting up some solar hot water gatherers, some solar panels, small pumps and fans you can really capture a lot of heat that ways too. the nice thing about such a set up is that it only runs when the sun is up anyways so you don't need batteries, but if if freezes where you are at you want the system properly designed so that it either drains back to empty when the sun goes away or the whole thing is set up as a closed system and the fluids are anti-freezed - my own preference would be the first one since that can be simpler.