Ollas: A Sustainable Solution for Modern Irrigation

How Ollas Irrigate Plants

An olla (pronounced oh-ya) is an unglazed porous wide-mouthed terra cotta watering vessel that is buried up to the neck in the ground near plant roots. The top part of the pot remains above ground so that it can be easily re-filled with water. A terra cotta top is fitted over the protruding opening to keep water in and contaminants out. When the soil around the olla is dry, the soil moisture tension slowly and evenly draws water out of the pot towards the surrounding earth thus continually irrigating nearby root systems. When the soil is wet no water is drawn from the olla and it remains full so that the plants are not over watered. The design eliminates surface evaporation and conserves water while delivering naturally filtered water directly to plants from below the soil. The filtering process improves the water’s pH balance and increases the level of electrolytes delivered to the surrounding plants, which improves the quality of the crops. This purified water is targeted to root systems, without attracting the insects and weeds that would normally compete for water coming from the surface.

How to Use Your Olla

Ollas come in many shapes and sizes, but they irrigate an area roughly equal to the size of the pot--a 1 foot wide pot will water an area with a diameter of 3 feet. They work most effectively in loosely packed, sandy or coarse soils that are permeable and allow a freer flow of moisture to draw water out of the pot. Wide mouthed vase-shaped ollas can be planted up to the neck in the ground or in a large raised bed or large pot filled with loose soil. Plant seeds, plants or saplings within the effective watering area, fill with water and cover. The olla does the rest. Check periodically to ensure that the pot contains water and add water as needed. Tear-dropped shaped ollas work on the same principle and are better suited to potted plants, small gardens, raised planters, and container gardens. Some models can also be used in clusters connected by a gravity or reservoir drip irrigation system. Bury the tear-drop olla with the funnel end in the ground near plant root systems, fill with water and cover with the fitted top. Leave space between ollas equivalent to the area they can irrigate, which is dependent upon their size.

A few caveats to get the most out of your olla:

• Ollas cannot withstand cold temperatures and should be removed from the ground before the first frost to avoid cracking.
• Ollas will not work well in compact soils and soils with high clay content since they inhibit the flow of moisture.
• Ollas work best with plants with fibrous roots (a network of thin roots with no primary root) as well as saplings, and immature bushes and shrubs. As saplings and bushes mature their strong roots systems may “attack” the olla for its water and cause cracks.
• Ollas are not designed to help with germination.

An olla (pronounced oh-ya) is an unglazed porous wide-mouthed terra cotta watering vessel that is buried up to the neck in the ground near plant roots. The top part of the pot remains above ground so that it can be easily re-filled with water. A terra cotta top is fitted over the protruding opening to keep water in and contaminants out. When the soil around the olla is dry, the soil moisture tension slowly and evenly draws water out of the pot towards the surrounding earth thus continually irrigating nearby root systems. When the soil is wet no water is drawn from the olla and it remains full so that the plants are not over watered. The design eliminates surface evaporation and conserves water while delivering naturally filtered water directly to plants from below the soil. The filtering process improves the water’s pH balance and increases the level of electrolytes delivered to the surrounding plants, which improves the quality of the crops. This purified water is targeted to root systems, without attracting the insects and weeds that would normally compete for water coming from the surface.