Ollas, (pronounced “oy-yah”) are a water conserving method of garden irrigation. Basically, it consists of terra cotta pots buried in the ground and filled with water. Since terra cotta is permeable, the water is drawn out as the soil dries. Plants near the ollas will get a more consistent source of water, which some plants really do well with. The more the plant needs, the more it draws. Theoretically, ollas use up to 50-70% less water and can deprive weeds of moisture by keeping the water down under ground = less watering, less weeding.
I first heard about it here (waldenlabs.com/the-most-efficient-irrigation-system-in-the-world/) and really liked the idea. Last summer we set up the greenhouse and went away for a month and it was a lot of work for someone to water. We wanted to have some system that we could leave for a few days, efficiently water the gardens, and hopefully reduce work. I could have just used a timer and a drip irrigation system, but I don’t like the idea of leaving the water turned on while we are away from home. When I read about ollas, I thought this might be the answer.
We decided to make our own ollas rather than order them for around $30 each. This means they are a bit smaller, and more water is distributed near the surface than the lightbulb shaped ones you can buy, but they are also way cheaper to make.
We made sure to use a silicone that is not toxic – we found one that is often used to fix fish tanks. We also drilled a small hole near the top to allow air out when filling. The kids are often given the job to fill them up and they can usually go a couple days before they need to be topped up again.
So far the ollas seem to be working well for us. We’ll see how it goes during the hot part of the summer, but next year I would like to try making more of them and a bit larger.