“Where do you get your clay from?” is a question I am asked a lot. There are two options: Option 1. I buy it in clean 12.5 kg bags mixed in Stoke-on-Trent or option 2: I forage wild clay. While buying clay is reliable and convenient, foraging for wild clay is unpredictable and exciting. Wild clay or marl (there are a lot of places with marl making up the name) can be found near fields (Marlfield), streams or along the shoreline.
When you come across and think you have found wild clay (which can be dry or wet) you can test it by making it into a ball and then forming it into a pinch pot. If the clay is very elastic it will hold its shape, if it’s “short” it will start to form cracks and fall apart.
A while back I found wild clay near Fethard-on-Sea and the clay was an amazing greenish colour, very exciting! I made a pinch pot, but it started to lose its shape. I brought home a handful of this clay, removed bits of stones, shells and organic matter and mixed it 50:50 with the white earthenware I have in the studio. It kept its shape and I was able to throw with this mix. The resulting vase was bisque fired and instead of the normal white, it came out of the kiln (intact, yay!) in a pale beige colour.
A good start into your journey of foraging for wild clay would be to train your eye to find it and then to bring a small amount home and experiment with it. Wild clay also makes lovely slips. It needs to be tested for compatibility with the clay you are normally using (small test tiles are ideal).
What is important though is to label your finds. Cleaning your foraged wild clay (by sieving which will remove shells, stones and other alien components) is necessary in order to prevent blow outs or explosions during the firing. Although in their raw state these wild clays can vary greatly in colour from green black or brown, after bisque firing they normally generate a large palette of beiges, oranges and browns. Happy wild clay foraging!