Diana Kersey

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Clay Pot Irrigation: "Ollas"
Why Ollas? Diana discovered ollas, or "pitcher irrigation" while writing a grant for a community garden in her neighborhood. They looked like a fun project to add to the garden, while making it easier to maintain and save water at the same time. Her community garden, the Olmos Park Terrace Community Garden won the grant from Green Spaces Alliance. The grant provided funds to buy clay to make the ollas and, under the supervision of Diana, the neighborhood worked together to make the ollas. The first year of the community garden was 2011, the year of record drought in Texas. The garden performed well under extreme circumstances and further convinced Diana that ollas were a viable means of irrigating. She has since refined her technique and process of creating extremely durable ollas and offers them for sale for $45 each. There are a few people that are producing or importing ollas for a little less cost, but Diana feels that the strength of her special claybody and decorative glazing techniques puts her product way ahead of the competition!
Ollas (pronounced “oya”) are porous hand made clay pots that have been fired in a kiln and then are buried underground. The body of the pot is left unglazed and the top, exposed portion and lid are glazed. When filled with water, the clay pot turns into an amazing high-tech device. The micro-pores of the clay pot allow water to seep into the surrounding soil. The water seepage is regulated by the water needs of any nearby plant's roots. When the plant's water demands have been fulfilled and the soil is moist, the water seepage from the clay pot will stop. When the soil becomes dry, water seepage will begin again. This seepage is controlled by soil moisture tension. It's automatic irrigation without timers or electronic sensors! 

How to Use:

1. Bury your olla in the ground or in the center of a larger container up to the glazed portion of its neck.

2. Place seeds or plants around the circumference of the olla. Fill the olla with water and place the glazed lid over the top to prevent evaporation and mosquitoes.

3. Continue to water the seeds or plants and keep the olla filled daily for a week or two to help get them established, then switch to just adding water to the olla. Mulch around the plants and olla to further prevent evaporation.

4. It is hard to estimate how often you will need to add water to the olla. Variables are: # of plants, amount of rainfall, types of plants, etc. Based on our experience, and using one bell pepper or tomato plant per olla, I only needed to add water about every 5-7 days during the drought of 2011! 

Advantages of Olla Irrigation:
SmileGood for soil structure. Because water is not poured onto the soil, the seed bed stays loose and plenty of air can circulate.
Smile Surface soil in clay pot irrigation remains dry, thereby reducing weed proliferation and direct evaporation!!
Smile System inherently checks against over-irrigation.
Smile Much smaller quantities of water and less frequent watering required, reducing the amount of labor and time needed to garden.
SmileSaves on the amount of fertilizer if it is added in clay pots and is absorbed as a solute via water movement to the plants.
Smile Clay pots have been proven to reduce water use without reducing yields.

1. Always keep pots wet by not allowing water to deplete beyond 50% capacity. This will counteract possible clogging and enhance water flow out of the clay pot.
2. Long irrigation intervals entailing total depletion of the pots should be avoided as this will encourage clogging particularly if the water is highly carbonated.
3. An acid (hydrochloric or vinegar) should be used to unblock the system if clogged.
Please feel free to contact me if you have any further questions.



Links about Olla irrigation: