How to Make DIY Ollas for Free Garden Irrigation
Growing your own vegetables is deeply satisfying. Like many gardeners, I’ve gradually increased the number of plants I grow and tried to make the most of every bit of space.
But setting up a productive garden isn’t cheap. Soil usually needs compost and fertilizer, and raised beds — while convenient — can be costly. If space is limited, containers become necessary, which also adds to the expense.
And in summer, many plants thrive in the heat but need regular watering. Especially when growing in pots, you may find yourself watering daily. Leaving the garden unattended for more than a few days becomes tricky.
One way to reduce watering needs is to use ollas.
Why Ollas?
Ollas are unglazed clay pots buried in the soil that slowly release water to plant roots. They’re a sustainable, low-tech irrigation method that saves time, water, and money.
They’re especially useful in pots or smaller garden beds. Watering a large, raised bed would require quite a few ollas, so their best use is in container gardens or small patches.
They’re not just practical — they also look beautiful nestled among plants. But like most gardening tools, they can be expensive to buy in quantity.
This post is about how I made my own ollas for free, using local clay and firing them in a basic fire pit. It’s not a quick fix, but it’s a satisfying winter project to prepare for next season.
Can You Make Ollas at Home for Free?
Yes, but it takes time and patience. Collecting and processing local clay is completely free. You’ll need to fire the clay, and while it’s not the same as using a kiln, it works surprisingly well for earthenware pottery. Temperatures in a homemade firepit will not get as high resulting in porous earthenware, exactly what you want from your ollas.
The process of making your own pottery depends on what you have around you. You will have to find a clay rich area and collect soil, process it, and fire it at home. It involves some experimenting and because the clay can vary in its texture and composition.
From my own experimenting and researching this is how I was able to make my own ollas. A valuable resource I found here.
Step by step: How I made my DYI Ollas
Follow along the steps I took to make my own free ollas.
1. Collecting Clay
Not far from where I live, the soil is clay rich, deep red. Along riverbeds, in dams and after rain it is easier to spot, especially for inexperienced potterers like me. I dug up a bucket full of wet clay and brought it home. Since it was from the edge of a dam, there was a good amount of visible debris in it that needed to be filtered out.
2. Processing clay
Filtering clay
There are two ways of processing clay, dry or wet. If the collected sample is dry (and ‘clean’) it can be ground either with a stone or a corn mill into a powder and then mixed with water to the desired consistency. Because my sample was wet, I went with the wet processing method.
The clay is mixed in a bucket with water to make a slurry and then poured through a fine mesh into another bucket to remove stones and debris. This step should clear most of the dirt from the clay. I then let it settle in the bucket. The clay will separate from the water and settle to the bottom of the bucket. This separation of the water from the clay should only take a few hours, but in my case took several days. Adding vinegar could help the process along. Eventually, the clear water on top, can just be poured off. A thick but still very liquid clay remains behind.
Drying clay
After cleaning the clay, it is too wet to use for pottery even after pouring off a lot of the water. To dry the clay to the right consistency it can be poured into an old cotton pillowcase and hung outside. The clay will stay in the pillowcase while the water will drip out. I found that it should not be left for too long in the pillowcase because the edges start to dry too quickly making the clay clumpy. To finish the drying process, I scooped everything into a shallow plastic tray and stirred it regularly for consistent drying. When I was happy with the texture, I kneaded it smooth.
3. Adding temper
Before the clay can be used to make pottery, a material called temper needs to be mixed in. Because clay is a plastic material it cracks when it dries. This means a non-plastic material needs to be added to prevent cracks and shrinking during the drying and firing process. Without this addition the risk of the pottery breaking during firing is high.
What materials can be used as temper? The only readily available option for me was sand. But there are other tempers, like grog. This is a powder made from already fired pottery and then added back to clay.
How much temper must be added?
About 20% should be temper. The amount to add is more difficult to determine when wet processing clay. When using dry clay, the temper is added before the water. The amount of temper is relative to the amount of dry clay. I just estimated the amount. With wet clay the temper needs to be kneaded in, which may take a bit of strength and effort.
In my first try, I made two samples of pottery with different amounts of temper. The one with less temper added, broke during the firing. Although not a scientific experiment, it led me to be rather heavy handed with the amount of temper added.
4. Shaping the Ollas
I’m not a potter by any means. I shaped my ollas by hand into a vase shape. You can get creative here, but I kept mine small and straightforward to suit my pots. There is no need to use a wheel to form pottery. To start out, I tried some basic small trays and cups and vases using the coil method.
5. Drying the pottery
This might take longer than you think, up to a week or two. A cloth can be draped over it to help with an even and slow drying. If they dry too quickly, cracks can from. In a humid environment like mine, the concern is rather to make sure the pottery is completely dry before firing.
6. Firing the pottery without a kiln
To ensure everything was completely dry before firing, I put it in the oven for about an hour at around 90C.
There are different ways to make an outdoor fire. Because I have an outdoor fireplace I chose to use that. Ideally the pottery is warmed up (either in the oven or around the fire) then it is placed onto the coals. I used broken pottery from previous firings to put them on.
Firewood is stacked around it in the shape of a teepee and burnt down. The firing itself should not take too long and once it is burned down, I let the pottery cool off before taking out.
The pottery turned out with a beautiful earthy tone. Some cracked (especially the thicker ones), but others held together well. With each batch, I’ve been learning more. I found the smaller and thinner pottery fired easier.
Reduction and oxidation
There are different environments of firing pottery which affect how the clay is burned. If oxygen is reduced (by smothering the fire after it burned down) it will change how the pots look because of the reaction/non-reaction with carbon. I have not experimented with this yet and don’t know enough to go into this topic.
Tips and Lessons I learned from making my own Ollas
- Let the clay dry completely before firing, no shortcuts.
- Thinner walls are less likely to crack (because they dry faster)
- If using a fire pit, expect breakage at first. Trial and error.
- Research different ways of firing pottery terms (oxidation and reduction firing) to experiment with the outcome.
This project isn’t fast, but it’s incredibly satisfying. If you have access to clay-rich soil and some patience, you can make beautiful, functional ollas without spending any money.
And they really do help reduce watering needs, especially during hot summers or short absences. For small containers or balcony gardens, they’re perfect.
If you found this interesting...
…you might enjoy this simple DIY seed starter box project I put together using recycled materials. It’s an easy way to give your seedlings a strong start — and pairs well with these DIY garden overalls.
