How did primitive potters harvest clay? People have been making pottery for millennia, and convenient hobby shops have only been a thing for a few decades at best.
Before that, people harvested their own clay right from the soil.
Clay is present just about everywhere, and even soils described as “sandy loam” can contain as much as 20% clay. To the naked eye, it may look like sandy soil, but with a 20% clay content, every 10 pounds of soil is hiding 2 pounds of clay ready for harvest.
With a little effort, you can harvest your own clay for craft projects or even something as advanced as a backyard bread oven.
Though most soil has some clay content, the yield will obviously be higher if you find high clay soils. Look for areas where the water tends to sit after a heavy rain.
Our soils are very shallow, and there’s usually somewhere between 8 and 18 inches of topsoil before a layer of dense clay. We’ve been working to slow the water runoff from our land, and the clay harvest happens more or less by accident while in the process of digging small slowing ponds.
If you’re curious how much clay your soil contains, try doing a test jar. Fill the jar about halfway with soil, add water and stir to completely break up soil particles. After a few minutes, any sand and silt will settle to the bottom. Anything that’s still left suspended in the water is the clay content.
This jar started at half full, and it’s now 1/4 full with silt, sand, and rock. I’d estimate that my soil sample is roughly 50% clay.
Testing the soil’s clay content in a jar.
There are two traditional methods for harvesting clay: dry and wet.
Dry Clay Harvest Method
The dry method involves completely drying out the soil, sifting it repeatedly and pounding the clay globs until it’s completely uniform and flour-like. This sifting is followed by a few rounds of winnowing the clay onto a collection surface.
The dried clay powder is then rehydrated and kneaded into workable potting clay.
This method is a great option in water-limited areas, but it requires a lot of time and energy. If you have baking hot sun and very little rain, it’s practical to completely dry earth.
None the less, the process of sifting, pounding and winnowing will take hours for just a few pounds of clay.
Wet Clay Harvest Method
The wet harvest method involves adding both water and soil to a bucket. The soil is then stirred into the water, and allowed to sit for a brief period to allow the rock, sand, and silt to settle out. The clay stays suspended in the water for longer.
The clay and water mixture is then filtered through a fine cloth or sheet. What’s left is a ball of smooth clay.
The wet harvest method is much more efficient and allows gravity to do most of the work. If you have access to plenty of water this is the way to go.
Up here in Vermont, we’re never short on water, and it’d be hard to find enough hot rain-free days in a row to completely dry the soil out for the dry extraction method anyway.
The wet extraction method is also a lot more fun, and allows kids to join in on clay processing. My 18-month-old was a huge help loading soil into the bucket and stir it up, and I couldn’t have asked for a more enthusiastic helper.
Processing Clay for Pottery
To use the wet extraction method, start by filling a bucket about 1/3 of the way with soil. Add water and use your hands to break up the soil particles as finely as you can get them.
Allow the soil to hydrate for a few minutes, or preferably a few hours. Then use your hands to break up the soil pieces again.
Give the whole bucket a good stir. A shovel works well for this, or a boat oar, or just an arm.
Our soil has so much clay suspended in the water that an arm in the bucket comes out completely covered in the clay slurry.
Clay and water slurry sticking to my arm as I process the clay using the wet extraction method.
Once the soil is fully suspended in the water, give the bucket a few minutes to settle. The rocks fell out of suspension almost immediately, followed by the sand.
The silt will take 2-5 minutes to settle down, leaving only the smallest clay particles suspended in the water.
While you’re waiting, get a sheet ready inside a bucket or colander. Anything with a fine weave will do, I’m using an old bedsheet.
The sheet has a relatively loose weave, so I’ve folded it into quarters.
The water moved through the sheet quite slowly, and I think next time I’ll just double it instead so I don’t have to wait 24 hours for the water to completely drain.
I’ve read in rural India, women who filter water through 7 layers of sari cloth actually filter out cholera. With 4 layers of bed sheet, I was able to filter a clay slurry to completely clear water.
I wouldn’t imagine that I removed bacteria, but it’s good to know that I can take scummy water and make it clear enough to boil for fresh drinking water.
My daughter has been drinking from our pond all summer using a life straw, mostly for novelty value. She gets a kick out of being able to drink right from the pond, but filtering the water to remove dirt first seems like a much more sustainable long-term solution for water.
With 4 layers of bed sheet, it took about 24 hours for the water to completely drain. As I said, 4 layers is definitely overkill.
Next time I’ll cut this sheet in half and make two clay extractors, each with two layers of a bedsheet.
To speed up the process, I gathered the corners of the sheet and hung it from a tree.
In the end, the top inch of clay was still pretty wet and slimy.
After 24 hours, I pulled all the clay out of the sheet, kneaded it together and let it dry in the sun for a few hours. At that point, the texture was just right.
Since it’s not commercial clay, it’ll take a bit of effort to learn how to fire it correctly. The right firing temperature may be hard to achieve, but our next step is to make a primitive kiln in the backyard.
I’m really inspired by the maker of the primitive technology videos on youtube, and he has a beautiful homemade rocket stove kiln. Temperatures in that won’t be exact either way, so it’ll be a learning curve regardless of the type of clay used.
I’ve read that inconsistencies in homemade clay can make it liable to crack during firing and that some potters actually mix in stones to their pottery vessels to help stabilize them. Soon enough I’ll find out when we go to make primitive pottery.
I can pull an unlimited amount of clay out of our soil without much trouble, so even if it takes a while to get the pottery process down it doesn’t much matter. It’s all part of the journey.
We worked our first lumps of clay into very primitive bowls, and thus far I’ve found that it’s much easier to make clay than it is to make attractive pottery.
It’ll take a lot more practice to make something worth firing, but in the meantime, we’ll try firing these practice bowls to refine our technique.
Overall, the process was almost effortless. Though I haven’t tried the dry method, there’s no way it could be this easy.
By description, it’s pretty grueling and it seems like you’d be inhaling a lot of clay dust in the process.
I’ll stick with the wet method and mud splashing with the kids.
Toni
I absolutely love this post, and I’m going to try your wet method for harvesting clay as soon as I can get a bucket filled with some of our clay-y soil and some water. I’ll let you know how it turns out.
Sasha
This sounds like the perfect project to do with my kids. I thought clay extraction would be difficult but this sounds so easy!
Quinn
I just have to say how much I LOVE your site! I always learn something new and unique! We’re building a home right now so there’s LOTS of almost solid clay laying around… time to get busy 😀
Ashley Adamant
Thanks Quinn =) You write one of my very favorite blogs, and I see you’re just getting another site off the ground too. Congrats!!!
John Jacob
That is an awesome blog note. I spend a summer in Kenai Alaska back in the 80’s, and a then young art student named Brian Bolden showed me that the silt at the mouth of the Kenai River going into Cooks inlet was pure enough clay and had a low enough firing temperature that it could go through a minor quartz inversion in a hot campfire. If I recall (and understood correctly), it had to do with the sulfur content in the clay due to the amount of coal in the area that caused it to do this. We built a kiln on the beach with rocks, clay and a scrap piece of culvert, then used low grade coal that was in the hill side to fire it. What a memory.
melissa
This is fascinating! My last garden had almost solid clay soil, I’m regretful that I didn’t try this! There are also spots along the coast of CA where there are ‘veins’ of straight clay.
I recently attended a women’s retreat and we did primitive pottery, but from store-bought clay, and fired them in a trash can. It was packed with sawdust, woodchips and the pottery bits, and then lit and slowly burned.
Charlotte Anderson
This is awesome. I cant wait to give it a try!
jane byrd
I love this blog, well done, i too am an off-grid homesteader, mother in the middle of nowhere in Portugal…. I too love primitive tech, i watch all his video’s, i hope to aspire to be primitive one day, love your work, keep posting, hope to see more.. one love <3
Nad
Thanks for a fantastic post! I was looking into this the other day, since I now live in an area where the soil pretty much is only clay! Do you have any insight intousing self-made clay that could – I have no idea whether this is even possible – somehow airdry, i.e. eliminating the need for a kiln? I’d love to give it a go and see if I like it before the incurring the costs associated with buying or building one. We have no such resources close-by so firing up in someone else’s sadly isn’t an option.
Ashley Adamant
We tried air drying ours and it looked great…then I handed it to my 1-year-old and he snapped it in half with his hands in under 3 seconds. It would have been nice if that worked, but at least for ours, it didn’t. I have seen primitive techniques that just bury them in a fire pit, which might be an option if you have a charcoal bbq grill.
Lisa Wilhelmi
Wow! You are most refreshing and informative. I appreciate your good works. Sincerely Yours – Lisa, Choctaw Nation of Oklahoma residing in California
Ashley Adamant
Thanks Lisa!
lindsey
can you also use this to make clay to make sculptures with?
Ashley Adamant
Yup! Or at least my little ones did. I couldn’t speak to high-quality art though…since I’m not super familiar with that type of clay and how it may differ from what we pulled out of the ground.
Brian
Years ago I read a book about people who recreated an iron Age village in England. They were lucky: before the year-long project started, they had a pickup truck load of commercial clay dumped for their use, so they did not have to use natural clay. But they found their pots kept on bursting asunder when fired, or they would fire well but then burst during use.
Turned out, the clay was actually TOO pure. Their pots improved when they added bits of stone or gravel. But either way it took a lot of practice and experience to get the firing process right.
I have long wanted to play around with clay, but it never occurred to me you could make your own from non-clay soil, until I saw the process described on the web!
Mady
I come from people who love outdoors but sadly imwent into fister care and my dad who took me into the forest is now dead and the people who are going to adopt me hate outdoors and finding this gives me something to do.
Ashley Adamant
Hi Mady, I’m sorry to hear that but happy you’ll have a new project. I hope you find the outdoor time you need, best wishes. -Ashley
Yusuf
I came from a google search and the article was so fun to read. I never expected it to be this good. Thanks for the effort.
Dragme
Im going to give you a protip: If you want to mix and match the “drying method” vs wet method then you can dig up a long, thin section of earth. Use what you dug up to process ina bucket of water. Swirl and separate clay from soil. Wait 5 minutes, then pour the water out into that same trench. Hold a few fingers in the water as you slowly pour it out from the side of the bucket. When you start feeling thicker, muddy consistency through your fingers, stop, fill the bucket some more with earth, and repeat this process. Once the bucket is half full of silt and sand, flip it over and pound the bottom so it drops out. Then do this again. Since the clay is in the ground, and since it is an open, long pit, it will dry within 1 to 2 days depending on heat, sunlight, etc.
Ashley Adamant
Really great idea, and saves needing a cloth to filter. Excellent!
Martin le Maitre
This post is PERFECT for my needs, THANK YOU!
I’m not actually wanting to make pottery, I just want some natural (and cheap) clay for bonsai landscapes.
I’ve asked various people and websites, and here at last is the answer!
Very impressed with your project, good luck with it! I see the post is over a year old, how are things progressing?
Blessings, regards. Martin – Joburg, South Africa.
Teresa Antosyn
I have some red rock from Utah canyon lands. It has been sitting in my back yard for almost 20 years. It has been crumbling over the years as it is soft in nature. Is it possible to turn it into clay…? Thanks, Teresa Antosyn
Ashley Adamant
That’s a good question that I don’t have the answer to. I have no idea what that would be made out of. Limestone that we have out here crumbles too, but it wouldn’t make clay.