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Spanish Colonial Olla Irrigation Makes a Comeback

ALBUQUERQUE - An ancient irrigation technique brought to New Mexico by Spanish settlers is making a comeback, and its reintroduction is benefiting Hispanics in Albuquerque's Southeast Heights.



Curtis Smith, horticulture specialist with New Mexico State University's Cooperative Extension Service, fills a buried olla in his garden with water. This olla will provide enough water for the three plants that surround it, hollyhock, lettuce and alyssum. (04/13/2005) (NMSU Agricultural Communications Photo by J. Victor Espinoza)

Irrigation with ollas (unglazed clay pots) is simple and extremely efficient, but the system gave way to modern watering techniques in New Mexico decades ago, said Curtis Smith, a horticulture specialist with New Mexico State University's Cooperative Extension Service.

"The conquistadors brought the olla system to the American Southwest, and it was widely used by Native Americans and Hispanics," Smith said. "It disappeared quite a while ago, but we're reintroducing it to gardeners because ollas are about the most water-efficient irrigation method available, and they're incredibly simple to use."

Under the system, gardeners fill unglazed clay urns with water and bury them near plants. The water slowly seeps through the porous clay, directly irrigating roots that encircle the urns to absorb leaking moisture. The tops of the ollas (pronounced OH-yas) extend above ground so the urns can be refilled as water is absorbed.

Ollas virtually eliminate the runoff and evaporation common in modern irrigation systems, allowing the plant to absorb nearly 100 percent of water, Smith said.

Smith is encouraging those in NMSU's statewide Master Gardener Program to learn about ollas and teach local gardeners to use them.

To assure an ample supply of the clay urns for gardeners, Smith has teamed up with East Central Ministries in Albuquerque and the nonprofit organization Seed and Light International to establish a small olla factory–the first one in New Mexico and likely the only one in the United States.

"The olla project is a perfect fit for us because we try to create micro-businesses that can provide jobs for local families and added income for our ministry," said John Bulten, director of East Central Ministries, which offers services to low-income families in the Southeast Heights.

The ministry invested about $1,300 last fall to buy a used kiln, workbenches, and other equipment for the olla factory. It now employs four people from the immigrant-heavy La Mesa and Trumbull Village neighborhoods, where the ministry is based. The factory makes nearly 100 ollas per week, which are sold through select stores in Albuquerque and Santa Fe, and to walk-in customers at the ministry.

To make the urns, the ministry created plaster of Paris molds from pumpkins, squash and gourds of various sizes. Workers pour liquid clay into the molds to shape the urns and then fire them in the kiln to solidify the clay. The urns, which are unglazed to keep the clay porous, retail for $12 to $15 depending on size, Bulten said. Proceeds help pay for ministry services, including Spanish-language educational programs.

Smith said the olla factory is filling a niche need as demand for the urns grows. "I give lots of lectures about this technology, and afterwards people always ask where to get the ollas, but until now we had no source for them."

Larry Sallee, president of Seed and Light International, works with Smith to educate gardeners and community organizations in Albuquerque about olla technology while providing technical advice to the ministry on producing the urns.

Seed and Light is a charitable organization that helps low-income communities worldwide improve agriculture by adapting low-cost, alternative technologies. The organization has helped introduce ollas in arid, developing countries like Afghanistan and Kenya, Sallee said.

"It's such a simple technology, and it's perfect for New Mexico," Sallee said. "It fits well with the state's cultural heritage, and it helps conserve water."

Smith says olla gardening can help homeowners in Santa Fe and other places who face watering restrictions.

"In places with water conservation ordinances, ollas can help maintain a steady flow of water to plants because the urns only need refilling once or twice a week," Smith said. "It's also good for people who go on vacation or who have busy schedules."

However, proper plant and olla selection is important. Gardeners should choose low-water-use, nonwoody plants, because woody plants can break clay urns as their roots grow, Smith said. They should match olla porosity, size and shape to plants' water needs, root size and root distribution. And gardeners need to place a cover over olla tops to avoid creating a mosquito breeding site.

"Interest is rapidly growing," Smith said. "The olla system appeals to gardeners because it allows them to rediscover old, creative ways of doing things."

For more information about olla gardening, call Smith at (505) 275-2576 or Sallee at (505) 298-0882.