By Brad Wier. This ancient method of drip irrigation provides consistent and reliable watering and it’s environmentally friendly. An ancient and efficient method irrigation useful for vegetable gardens, raised beds and containers, an olla is an unglazed clay pot buried and filled with water. Water slowly seeps right through the porous clay wall into the surrounding soil.
It’s an effective method of providing water to the roots of growing plants. In this case, the roots eventually encompass the pot and grow deep into the soil.
The irrigation is dictated by the moisture tension in the soil itself. Once your plant’s moisture needs are satisfied, seepage from the pot stops. When the soil dries out, it begins again.
In addition to keeping plants watered, an olla has additional benefits over surface irrigation: the soil surface stays dry, reducing weed germination and it prevents gardening soil from becoming compacted.
You’ll want to use an olla with a long-enough neck to keep it partially exposed above ground for easy refilling. You’ll also want to use a lid to prevent evaporation (and mosquitos).
Although a variety of ollas are available commercially, it’s also possible to build your own by gluing small clay pots and lids together.
Ollas can be refilled weekly or as needed.
Brad Wier is a SAWS Conservation Planner. Years in South Texas landscaping and public horticulture gave him a lasting enthusiasm for native plants that don’t die when sprinklers — and gardeners — break down. He’d rather save time and water for kayaking and tubing. He is a former kilt model, and hears hummingbirds.