Thanks guys, sorry for the tardy response, I've been away for the last couple of weeks. You've given me a lot to think about, doesn't really sound like solar is going to be an effective way to go here, but i'll keep playing with things and see if I can't incorporate some of the other non electronic suggestions as well. I'll let you know if I come up with anything interesting... while I build my green house, which should be much easier to integrate some fun electronic controls into!
Thanks again,
Joe