The first time we spotted an olla (pronounced oh-ya) watering vessel, we were immediately intrigued. An ancient method of irrigation, watering via an olla involves burying an unglazed clay vessel (the olla) in the earth in your garden and filling it with water. The water slowly seeps out of the porous clay into the surrounding soil, providing continuous moisture to the nearby plants. 

Olla irrigation is making a comeback as summers get hotter, and also as more gardeners have taken an interest in growing their own food, says Josh McWilliams the co-founder of GrowOya, a 10-year-old company that makes modern-day ollas. McWilliams read about olla irrigation when researching ways to water his vegetable beds while working as a chef and raising two young kids. “I wasn’t looking for a solution for my 30-acre field, I was looking to support gardening as part of a busy lifestyle,” he says. “I wanted to be able to go away for a weekend, but drip irrigation didn’t make sense for one or two beds.” At the time, McWilliams couldn’t find any ollas to buy, so he found a partner and started making them and selling them at farmers markets in Vancouver. GrowOya has sold hundreds of thousands of them since.

A raised bed is an ideal place to use ollas. McWilliams notes that they work best with plants with creeping vs. tap roots. You can still use them, but you’ll need to be strategic where you place your carrots and parsnips.

If you’re intrigued by this low-fi, eco-friendly method of watering read on for five reasons to love this ancient practice, and six ollas you can buy:

1. Olla watering is low-tech.

If you can dig a hole, you can install this irrigation. Olla watering is the epitome of low-tech, which is especially appealing to anyone with a small garden bed for whom drip irrigation would be overly ambitious. And being low-tech, it is also relatively affordable.

2. It’s also super-efficient.

Not only are ollas a low-effort style of watering, they are a very efficient one: Watering below the soil reduces evaporation. The non-profit organization Ecology Action tested five 5-gallon ollas in a 100-square-foot garden plot and found that 1.25 gallons of water per olla seeped into the soil every four days. Olla watering can also encourage roots to grow deeper, making for more drought-resilient plants. 

3. Ollas are inherently plastic-free.

Almost all modern irrigation systems, including water-saving drip irrigation systems, rely on PVC pipe and drip lines that do not biodegrade but must be replaced with some regularity as they wear out.

4. You can DIY an olla.

Monica Chavez, the content creator behind House of Esperanza, made her DIY ollas out of two simple terracotta pots, which she sealed together with a non-toxic water-based glue.  

5. An olla can babysit your plants.

Perhaps best of all, watering via ollas gives you a free pass for a weekend (or even a week away) without having to beg your neighbors to water your plants. Fill them up before you go and your plants will stay hydrated; larger ollas can go up to 7 days without filling.

Olla Vessels to Buy

See also:

• 5 Old-Fashioned Tools for the Modern-Day Gardener
• 10 Easy Pieces: Terracotta Plant Nannies
• 10 Things Nobody Tells You About Watering Your Garden