have a look here for a good explanation The Clay Refrigerator - Backyard Garden Survivalists - tribe.net
Just remember that Evaporative cooling only works well, in Low Humidity Environments, like Aridzonia, and Utah.... . YMMV....
ccc...^^^...I hear you...When our humidity gets below 50% a cold front is here...Since it's now cold outside..I can't use it...other than growing veggies...
Some gent won the Nobel Peace Prize by giving thousands of these to remote African villages. At least he did something--unlike nobammy.
Or a 'stealth beer cooler' at the office. Holds a Rhodadendron one day, a six-pack of Budl Lte the next!
A flower pot cooler! wow I've never thought of that but I like this idea! It seem to be also useful when you go camping And it's practical since I have flowers delivered tomorrow with serenata which came in huge pots! Now I have a use for them finally, because the flowers are already dead and gone haha*