Ollas and how to make them.

An olla is a Spanish (or some say Pueblo) device for maintaining a garden in a desert climate. Basically it is an unglazed clay pot, usually long and narrow, which is buried in the ground up to its neck within a garden and then filled up once a day. The water seeps out of the unglazed clay, right to the roots of the plant.
I purchased two ollas from High Country Gardens last summer and the only problem I had was that I immediately wanted more. Thus the homemade olla was born. I won't claim that this is effective as a centuries-old Spanish/whatever traditional method, but it does work. Take a plastic soda or water bottle, take the label off, and then poke holes all over the bottle with a pin. You need to make a lot of holes and it's a good idea to test it by filling the bottle with water. (Over time dirt will clog the holes and you'll need to make some more.) Then bury the bottle up to the neck, just like an olla, and keep filled up.
I use ollas particularly for plants that are not meant for the desert, like rosebushes and hibiscus. It gives them that extra dose of water that keeps them alive through days of 100+ temps.