I used a shallow plastic tray that held about a square foot of ice (which turned to cold water after 2 hours) but didn't see the drop in temperature I was hoping for - though the humidity went from 20 percent to 50! Considering fabricating a mini- swamp cooler. Have a small fountain I can use to run water over a wash cloth with a fan behind it. Thinking the moist air blowing over the plant will help increase the temp. drop and provide humidity too.
Let me know how you make out, T