Ollas (pronounced “oy-yahs”) are unglazed clay/terra-cotta pots with a tapered neck, used for irrigation. They are buried in the ground and filled with water, with the top of the neck exposed above the soil surface. There is evidence this ancient irrigation method was used in China over 4000 years ago. Ollas can result in a water savings of 50-70 %, particularly for vegetable crops.
When the soil around the olla is dry, the water is drawn out through the pot’s “pores” to thirsty plant roots. If the soil is moist, the water stays in the pot. The roots of your plants eventually grow toward and around the ollas, allowing for even and consistent watering.
To use ollas in a garden or farm, bury the olla in the soil leaving the neck protruding from the soil. Mulch should cover the neck of the ollas. Fill the ollas with water and cap the opening to prevent mosquito breeding, soil intrusion, and evaporation. How often you will need to refill your ollas depends upon the soil type, surrounding plant density, and weather. To maintain optimum water transfer, you should refill when the ollas are half empty. This will also help to avoid the buildup of salt residues along surfaces of the ollas that could impair the desired seepage.
Our terracotta ollas are available in medium (2 gallons – 36″ dia. irrigation) and large (3 gallons – 48″ dia irrigation). We offer these ollas with or without the neck and cap painted with white non-toxic milk paint that is mixed with an outdoor additive to prevent evaporation and inhibit mildew.
At this time, ollas can only be purchased for pick up or delivery in the San Diego area. We will contact you after your order is placed to arrange for free pick-up or delivery.
Other benefits of ollas irrigation:
- Ollas irrigation protects plants from water stress because soil moisture is consistent and plants get exactly the water they want, no more or less.
- Weeds do not prosper with ollas irrigation because the soil surface remains dry throughout the growing season. When starting with seeds, plant them a few inches from the olla opening and water the surface water until the seeds germinate. Once the seeds sprout, you can discontinue watering the surface to encourage the roots to seek the water from the ollas. If you start with seedlings you should only water the surface once to get the system primed.
- Because you refill the ollas by pouring water through the openings, it is quite practical to use greywater collected in buckets to irrigate your garden.
- Ollas keep your soil healthy because the soil of the bed under the clay pot system doesn’t get sealed by water impact and remains loose and well aerated.