Olla gardening is an ancient method of plant irrigation - considered the original drip irrigation system, Ollas are unglazed clay pots buried underground along side plants. The pots are filled with water, which then gradually seeps out through the porous walls into plants root zones. The Ollas are a very efficient watering system, especially convenient for regions that are prone to drought, and helpful for people who may have black thumb.
The Olla system is incredibly low tech and easy to use. Just fill the pots when the water level is low, and let the clay pots do the rest of the 'work.' The clay pots eliminate the common runoff and evaporation problems of typical irrigation systems, while allowing the plants to absorb nearly 100% of the water.
Ollas can be used with nearly any type of garden, but should avoid areas with woody plants, as their roots can break the pots. Additionally, ollas should match the size of the plants - shallow rooted plants should be matched with shallow ollas, etc.
You can make your own Ollas if you're handy with the wheel, you can craft one out of standard inexensive clay pots (use the tray as a lid), or buy them online at the Peddler's Wagon for $20-27.
Watch this video for quick and easy instructions:
(Originally posted on 3.9.2009 - JL)