Brandee Gruener is a writer in Durham, N.C.

This article applies to:



Using the Olla to Beat the Summer Heat
by Brandee Gruener       #How to   #Irrigation   #Sustainability and Self-Sufficiency

You can make an olla out of an unglazed clay pot, a matching saucer and a tube of silicone caulk.

Keeping the vegetable garden hydrated during the heat of the summer is a challenge when the sun beats down for weeks, the rain barrels run dry and even heat-loving crops wilt under summer’s fiery breath. Water restrictions have even become commonplace in many parts of the country, making watering the garden even more difficult.

Water-efficient systems such as drip-line irrigation can make a big difference. But gardener Scott Belan found a cheaper and simpler solution by building an olla out of a humble clay pot. This watering solution satisfied Belan’s personal philosophy in gardening: Look to the cultures and climates that make the most sense for your surroundings.

Ancient Mediterranean people buried ollas, or unglazed clay vessels, to slowly seep water into crop soils. Spanish settlers first introduced the idea of irrigating with ollas (pronounced oy-yahs) to the Americas. The concept is regaining popularity among environmentally minded gardeners.

Every gardener frets over keeping summer crops irrigated, but Belan, a member of The Nature Conservancy’s international climate change team, probably spends more time thinking about it than most.

“I think water is probably the biggest issue related to climate change that we’re going to deal with in the next 10 to 15 years,” Belan said.

He is constantly experimenting with ways to conserve every drop of water he can. Belan has five rain barrels that hold 300 gallons of water, a downspout that irrigates a backyard bog garden and now the ollas.


Making and Installing an Olla

Belan keeps pests out of his ollas with old brass finials he found around the house.

Ollas can be purchased from suppliers like Urban Homestead Supply (, or you can make your own with an unglazed clay pot, a matching saucer and silicone caulk. Shorter pots work well for plants with a shallow root zone, while taller ones are more beneficial for deep-rooted plants. A narrower vessel takes up less space in the garden.

Place a saucer on the top opening of each pot like a lid. Use silicone caulk to seal the vessels. After the caulk has cured, bury the pots upside down in the garden, leaving the drainage hole exposed. Keep the pot filled with water, and because the clay is unglazed, the water will seep out slowly, keeping nearby plants well watered.

Belan uses whatever is handy to keep pests out of his ollas, including brass finials, wine corks and rocks.


The Results

Red okra in Belan’s garden grew significantly taller due to irrigation by the olla.

The first year, Belan planted cayenne peppers, rainbow Swiss chard and red okra in two raised beds irrigated by ollas. As a test, he irrigated only one side of his okra bed. Plants directly surrounding the ollas gained the most benefit and grew significantly taller.

During hot spells, the water would sweat out every two or three days. That’s less frequent than the daily watering that many vegetables require in summer. Water is often wasted while hand-watering large areas, with even more water lost through evaporation at the soil surface. As an additional benefit, ollas don’t get foliage wet, which can attract disease.

Since discovering that his ollas have a limited range, Belan has decided to use them this summer for vegetables that are traditionally planted closely together in a hill. “I'll be planting a small cucumber called ‘Silor Mini’ in one olla bed this year, and basic heirloom patty pan squash in the other,” Belan said.

Belan also believes strongly in using plants that adapt well to the climate. Because of that and his culinary interests, he plants a variety of Asian greens he can cook up in stir-fries through the summer.

Being immersed in the science of climate change has led him to think about gardening in different ways. Ollas have helped him survive the hardest part about gardening in the South – the summer.


Tips for Using an Olla:

-Use unglazed clay vessels so that water can wick into the soil. Clay pots work well, but a jug with a narrow neck will take up less of your valuable planting space.

-Seal the open end of each clay pot with a saucer and silicone caulk. Once you install the olla, almost anything can serve as a cap – a handy stone or even brass finials and wine corks.

-The olla benefits plants growing directly around it. Plant seeds in a circle around the vessel.

-Vegetables traditionally planted in a hill, such as squash, melons or cucumbers, lend themselves to this type of irrigation.


A version of this article appeared in a July 2011 State-by-State eNewsletter.
Photography courtesy of Brandee Gruener.


Posted: 06/20/18   RSS | Print


Share this story on:
Facebook       Twitter            

Other People Are Reading



mickmick6 - 07/05/2011

I have used 2 liter soft drink bottles put the tops on tight and drill a hole, cut off just enough of the bottom to fill with water and bury it leaving about an inch above gound, when filled with water it seeps in to the soil slowly.
{screen_name}'s avatar