‘Olla’ Efficient Irrigation System

Olla is an unglazed terracotta clay pot that’s buried next to plants to water them at a steady rate, especially effective in hot and dry locations.

The pot is buried in the soil next to the plants that you would like to irrigate.


Water is added to the pot and capped to prevent bugs from entering.

Curtis Smith, horticulture specialist with New Mexico State University's Cooperative Extension Service, fills a buried olla in his garden with water

The unglazed clay of the pot slowly releases the water on demand when it senses negative pressure caused by nearby plants. Plant roots suck up the water from the soil, creating negative pressure outside of the pot and drawing the water inside it out into the soil.


This interaction between the plants and the pot is highly efficient, without just seeping the water out continuously and evaporating. Some of the reasons why it’s called the most efficient irrigation system in the world, include the fact that it:

  • Uses 50-70% less water, making it a good compliment to rainwater harvesting.
  • Controls soil moisture levels to prevent over-watering or drying out, reducing irrigation labor.
  • Reduces weed cover by not watering the surface rooting plants, which allows planting by seed and nourishing the desired plants.

Here are instructions how to make an inexpensive Olla at home in 7 simple steps.



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