How to use a terracotta olla for easy, water-wise gardening

What Is a Terracotta Olla?

An olla (pronounced oy-yah) is an unglazed terracotta pot that’s buried in the soil and filled with water. Because the clay is porous, moisture seeps slowly through the walls and goes straight to plant roots. It’s a sustainable and ancient technique used for thousands of years in dry climates and it can still outperform many modern irrigation systems.

All you need to get started is your olla, a trowel and a watering can or hose. 

Why Use a Terracotta Olla

Terracotta ollas are perfect in Australia's climate. Our long, dry summers and unpredictable rainfall make water efficiency crucial. Ollas release water directly to your plant's roots which means there's almost no evaporation, unlike surface watering or a sprinkler. This means less water wastage, strong root systems and a more cost effective method of keeping your plants happy.

If you're a gardener that's away a lot or one that forgets to water, they're the perfect addition to your tool kit. In addition, using an olla really couldn't be simpler. It only takes a few minutes to set one up and once it's in place, it can be used over and over with almost no maintenance. 

• Saves water, money and time: minimal evaporation or run-off
• Low maintenance: fill once or twice a week
• Healthier plants: steady moisture at root level
• Perfect for Australian gardens: ideal for raised beds, veggie patches and natives that dislike constant surface watering
• Versatile: an olla can be used in many locations, from outdoor garden beds and herb planters to indoor plant pots
• Cost effective: an olla needs little maintenance and can be used repeatedly

How to use a terracotta olla - step by step instructions

Choose the spot for your olla

Select your spot indoors or out; this could be a bed or large pot where you’d like even moisture distribution. An olla covers roughly a 20–30 cm radius but this can vary depending on location and soil type as well as the size of your olla. 

Dig a hole a little smaller than the height of your olla

Make it deep enough that the olla’s neck sits level with the soil surface. The goal is to bury the body while leaving the opening visible.

Place and backfill your olla

Set the olla in the hole and backfill soil firmly around it so there are no air gaps. This ensures good contact for moisture transfer. Avoid pushing any soil into the top of the olla. 

Fill your olla with water

Pour water in your olla until full. You’ll notice the clay darken slightly as it begins to absorb.

Cap the opening of your olla

Use the terracotta lid to close off the top of your olla. It reduces evaporation and keeps out insects or debris.

Plant around it if the bed isn't already established

Position seedlings or established plants near the olla, giving a clearance around it. The roots of your plants will naturally seek out the moisture wicking from the olla.

How Often to Refill your Olla

Check the water level every few days at first. In hot or windy weather you may top up twice a week; in cooler or shaded spots, once a week is usually enough. The soil should stay evenly damp — not soggy.

Caring for Your Olla

• Empty and dry over winter if frost is expected.
• Avoid sudden temperature changes or dropping it — terracotta can crack.
• If algae forms, scrub gently with a soft brush and rinse.
• When planting new beds, simply dig the olla out, rinse and reuse.

Where to Find One

You can find the same terracotta bottle olla I used in this guide here — simple, functional and beautiful in any Australian garden.

Final Thoughts

Sometimes the best gardening tools are the simplest ones. A terracotta olla requires almost nothing and gives your plants exactly what they need — slow, steady water and less stress for you. Bury it once, keep it filled and let it do the work while you enjoy your garden. 

Click here for more water-wise techniques.