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water-conserving irrigation devices

An olla (pronounced "oya") is a simple subsurface irrigation device whose design and use dates back many thousands of years. It is an unglazed pot which is buried up to the neck in the soil and filled with water. The wall of the pot is porous, and water seeps through it into into the earth by a process called soil moisture tension. When the soil around the pot is moist, water remains in the pot. As plant transpiration creates a demand for water, more is released through the wall of the olla. This is an extremely efficient process, often resulting in a very significant reduction in water use compared with drip-feed methods.

  • Water savings of 50%+ (cf. hose, drip feed)

  • Reduced runoff, evaporation, deep soil percolation

  • Reduced development of weeds

  • Reduced frequency of irrigation labour

  • No overwatering

  • Irrigation delivered directly to the roots

  • No moving or powered parts, and no plastic

  • Liquid nutrients and fertilizers can be added to water

  • Increased yield

  • Relatively inexpensive and rugged

  • Reusable over a prolonged period

  • Suitable for gardens and raised beds

  • Effective during water-use restrictions / hosepipe bans

15 seconds = 15 minutes elapsed time

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