Ollas is unglazed clay pots, filled with water and it is an ancient method of plant irrigation. The first writing about the technique dates back about 2 000 years to China. It has since been practiced in many arid regions of the world including New Mexico. Introduced here by the Spanish and utilized in local scale agriculture since the Columbian Exchange, the use of clay vessels has been largely replaced by modern drip irrigation technologies.
Modern clay capsules can be made from ordinary terra cotta flower pots found at nurseries and big box stores. The same principles apply because the pots are unglazed and porous, but an olla is open to the air and a clay capsule is closed or sealed and fed by tubing that keeps it full of water at all times. Because the capsules are sealed they can be plumbed together to work as a unit and they can also be used as a low pressure drip system.
Porous Clay Capsule System Diagram
More information on Ollas can be found below:
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