Watering Woes? Ollas To the Rescue!
Solve all your watering issues with clay pot irrigation, also known as an "olla," hailed as “the most efficient irrigation system known to man." How do ollas work for you in the garden?
Every gardener knows that a vital aspect of a successful garden is water. Your plants need water to grow and produce. But if you live in areas prone to drought, have very warm summers, or need to be away, keeping your plants well-watered can be a challenge. This is where the olla clay pot comes in!
What Is An Olla?
It’s got a funny little name, but it does serious work. An olla (which literally means “pot”) is a round, unglazed terra cotta clay pot with a long neck that you fill with water and bury next to your plants. It irrigates in the ground.
How Do Ollas Work?
The concept is simple: ollas keep your plants watered through a process called soil moisture tension. When the soil around the olla is dry, the water is pulled out through the pot’s “pores” and provides it to thirsty plants. If the soil is moist, the water stays in the pot. The roots of your plants eventually grow toward and around it, allowing for even and consistent watering.
This is not a gravity feed system, like holes in a milk jug where the water continues to flow until empty, but rather a tension concept, where the olla is wet, and the soil is dry. The best part: it won’t over or underwater your plants—it’s as if the olla knows what the plants need! This supply-and-demand system proves to be very Earth-friendly by saving between 50% to 70% in water use.
Olla History
Clay pot irrigation can be traced back thousands of years. It was designed during a time when watering meant hauling water in vessels. Anthropologists have been digging up unglazed clay pots from long-forgotten ancient garden sites, from China to South America. Those unglazed pots solved a lot of civilization’s water issues: they were inexpensive and could go days without filling. Nothing has changed: clay pot irrigation still does all that.
Which Olla Do I Choose?
Ollas come in a variety of sizes. Choose one with a lid to decrease evaporation and one that fits the space you’re watering. The larger the olla, the less often you have to fill it, and the larger space it will water. For example, a 2.9-gallon/11-liter pot will water a three-plus-foot diameter circle for 3 to 7 days. That works well with a 4 x 4 garden or raised bed. Smaller pots will water less and are better suited for small-space gardens. If you’re heading out on a trip or vacation, ollas are like that helpful friend who cares for your plants while you’re gone. Simply water your plants well and fill your olla. A week later, you will return to happy plants.
Benefits of the Olla – A Snapshot:
- They conserve water. They save between 50%-70% in water use.
- They’re a time saver. No hauling water jugs, positioning hoses.
- They’re inexpensive.
- They produce healthier plants. Because soil moisture tension creates an environment where roots get slow, even watering around the clock, the root base grows larger, producing a healthier plant.
- There are many sizes to choose from. They can be used in raised beds and container gardens.
- Fertilizing is easier. Add a liquid fertilizer directly to the clay pot—it uses 1/3 less fertilizer, another money saver!
- They’re low-tech. They’re easy to use—anyone can do it! And no electricity needed.
- They’re a vacationer’s friend. Perfect when planning trips, during a busy work week, or when rain is sparse—larger ollas can go 3 to 7 days without filling.
- They’re Earth-friendly. Ollas are organic, made from clay. They leave no plastic residue in the earth for the next generation to worry about. Ollas are great neighbors to the environment and earthworms alike!
For more information on ollas, visit the Dripping Springs Ollas web site.
Mary Kathryn Dunston
Mary Kathryn Dunston has been an avid gardener for decades, as well as a health advocate. She currently works for Dripping Springs Ollas, a company dedicated to helping others help themselves, by supporting community and school gardens with water conservation. You can contact her at [email protected].
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Mary Kathryn Dunston#molongui-disabled-link
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Mary Kathryn Dunston#molongui-disabled-link
I am using unglazed terracotta pots. I plug up the bottom hole with painters putty which works well. I cover it with a plastic lid However, when I bury it, the water level never goes down, even after a couple days. Am i doing something wrong?
There may be a few reasons for this. One could be that your soil is adequately hydrated, and so it has no need to pull from your ollas. Another could be that your terracotta is actually a mix of materials and some may not be conducive to passing the moisture through the barrier. One recommendation I would make is to use a terracotta saucer as the lid. It may not be of benefit, but I have had success with that set up. Best of luck to you!
What about winter? Do you pull the ollas out? Drain them but leave them in the ground?
they break, used several of these, water drained completely out in a couple of hours, threw them away
Did you make them or buy them? Did they break because they froze over the winter?
They are fragile and will crack when the ground freezes. Youll need to dig them up and store them over the winter.
I made my own, cost about $5 in clay and firing services.
Have you used large ones for an entire bed as told above? Have you used terra cotta pots, I don’t have access to to throwing my own.
The biggest difference between the ollas in the article and the clay gardening pots in the Big Box store is the clay itself. Olla clay is chosen for its contents that will burn off in the kiln, creating thousands of tiny holes which allow water to flow through the olla wall, watering the plants around it. Big Box store clay pots want the water to stay IN the pot to water the plants, so as little water as possible goes through he walls.
The ollas in the article have been tested in Ontario, Canada for years. They didn’t break through the winter, in the ground. The key is to have the olla DRY before the first frost or freeze. However, if your area is prone to sudden rains and then a sudden freeze, then no terra cotta product can with stand that weather. An olla works by having holes in the wall of the olla, allowing the water to pass through the wall of the olla. So obviously, if there is water in the holes, and they expand during the freeze, then you know what happens, the frozen water wins.