Meadow wanted clay for making cob. However, the yard soil produced a silty clay, rather than a pure clay. So she wondered if she could get more clay from the humus down in the swampy area of their woods (this area needs to be cleaned out to place a path through there, and there is more than can be used in the garden). So this was the experiment. She made a clay slip and is letting it dry.

Here is the humus she started with, in the bucket.

Black humus, ready for processing

Meadow added water to the bucket and mixed up the humus, then poured it through a sieve that was placed over a second 5-gallon bucket. A lot of organic material was removed from the clay slurry (slip), and was saved for the garden.

Water was added, then mixture poured through the sieve to remove the aggregate

After all the slurry was pushed through the sieve, and the organic matter removed, what was left in the bottom of the bucket was this weird ‘fluffy’ type of material, which was spongy and light.

The bottom was NOT more aggregate, but a fluffy mixture that was neither sand nor silt, but organic matter

Figuring that the clay was already in the suspension, Meadow removed this fluffy organic material from the bottom fo the bucket and did not add it to the rest of the mixture (utilized in a clay slip). Instead, she used the humus in a separate experiment. (will get to that later)

The Clay Slip

The bucket below the sieve was filled with slip (she hoped), so she poured it into the tarp (an old drawer was used with sides to hold it in from spilling everywhere).

Old drawer frame for trough/tray
Tarp placed in frame as a trough/tray for the slip
Clay slip in the trough/tray

The slip in the trough or tray was then covered over so it could evaporate slowly. If the clay dries too fast, then it can become too hard on the top and still mushy on the inside. Slow evaporation produces less cracking, and a better quality (more evenly made) clay for using in projects.

Whether this clay-from-humus experiment works or not will remain to be seen… keep watch for updates!

Follow up article: “Making Clay or Insulation… Out of Humus?”