Natalie, I forgot to mention that the more water you have in there, the better it is supposed to work, so that is why we have double decker barrels. It is not attractive in the least, but it works and saves money. Also, there is space on top but not enough for more barrels, so whenever I have a cat litter plastic containers (scoopable kind of litter) empty, I fill themt with water and put them on top, too. If you have any questions, I'm glad to help. I have seen this used in other types of greenhouses, too.
