green house info

I'm planning on building a greenhouse next year, I need some electrical help and info on solar panels, it would help alot.
First I need to buy a solar panel, two 8''fans, extension cord, and a rubbermaid container from canadian tire. where should I mount the fans?
I need one fan to suck in the fresh air and the other to blow air out. I'm not sure if the fans will turn on when the sun comes up or turn off when the sun goes down and where would I mount the solar panel so It won't get wet.
How many 4' plants can fit in this green house and will it work?
Thanx.

I guess no one cares.

Thandx man, Its about time I got some info.LOL
I thought of rolling up the plastic sides when the temp gets hotter so air can circulate. I thuoght of growing all kinds of auto flower strains, so this will be a cool grow this year. I'll post pics of my grow.