After installing DIY ollas—unglazed terra cotta pots buried in the soil that slowly release water—in my raised vegetable beds, I wanted to know whether they actually delivered enough moisture to my plants. After several weeks of use, I had some interesting observations.

The question is, are they working? I had installed just one to begin with and filled it with water. After 2 weeks the water level inside barely dropped an inch. Was that just evaporation? Or was this thing not working? I asked that question in the comment section of that original video I spotted on Instagram.

The response was enlightening. Maybe my soil was staying hydrated enough, she said. I had dug down alongside the buried pot and while it didn’t feel wet, the soil didn’t feel dry either. Keep in mind that this was buried in a raised bed which I had filled with some really moisture-retentive raised bed soil. While my plants would look a bit droopy, that could have been the result of very hot (heat wave-type hot) days that typically bring any well-watered plant to its knees.

Testing Ollas in a Second Raised Bed

I did bury a few pots close to my zucchini plants. The water level in those drops a bit faster, likely due to the greater evaporative surface of the zucchini’s leaves, and hence the more water they are taking up from the soil. So, yes, these ollas are working.

Is there a downside? Yes. You need to bury the ollas fairly close to the plants, which means you do lose some growing space in the garden. That’s not so much a problem with the zucchini bed because those plants cover so much ground. But in a bed of lettuce or carrots, you would lose a lot of production space.

My other thought is that I don’t actually need these in my raised beds because my soil is in really good condition. In-ground garden soil is different, as native soils can be less moisture-retentive. I suspect I had buried an olla in the ground, it would need refilling much more frequently. Maybe I’ll bury one just to see what happens.