yeah air was my only concern ... so i made this plan for you! i think it seems good .. its with one of those rubbermaid garbage cans never did it before but it seems good
cut bottom out of garbage can
cut air holes around bottom of upside down garbage can
make risers for lid to sit on at top of the upside down garbage can
glue lid to risers
make sure over hang of lid is lower than to top of the upside down can
there hope you like it
just pieces of anything to just lift the lid away from the bottom of can .. i tried making a pic but it wouldn't attach .. like this sorta I___I___I___I thats bottom of can with risers
just put tall stakes in the ground around it... 5-8 feet tall, and put a big thick blanket on them at night, or to be more precise, exactly 12 hours after the first get sun (have you done shadow measuring before? There are tons of website that track the suns/moons movements and predicts how the near future will be also, it helps to check them occasionally. P&K never hurt either...