Be sure to darken all 4 sides somehow. paint or tape paper around it. if she gets to the bottom and can see out the side it may disrupt her. once she gets started, there are to be NO interuptions. those can lead to bad things. i buy rubbermaid bins from walmart at $2.97 each. they are about 12w x 12h x 16l. you can use a 5g bucket, flower pot, even a trash can. rule of thumb is 12in of dirt deep. however i've seen 8in work. just remember your chams life literally depends on her laying those eggs. eggbound is BAD news.