Horse Tails and Ash Glazes

In her new book, Natural Glazes: Collecting and Making, Scottish potter Miranda Forrest sings the praises of the common horsetail. Not horsehairs, which are popular with potters who burnish and pit fire porcelain pots thus creating delicately beautiful surface lines, but horsetails, Equisetaceae, the flowerless plant found throughout most of the world these last one hundred million years.

High in silica content, Equisetacae have been used as scrub brushes in several cultures including that of colonial America. They are poisonous to livestock and, in many regions, considered invasive. They grow in the heavy clay beneath my pink Meidiland roses and, though a weed that I battle every summer, I do think they are pretty. I like the jointed, bamboo-like stems and the scratchy green bristles. Now there is a reason to love them.

Forrest writes, “The first test with horsetail ash alone produced a melted, creamy, greenish glaze with an optical blue in the centre, perhaps the most interesting single land-vegetation result to date. It also mixes well with other ashes and rock dusts. One of the other interesting effects associated with horsetail is carbon trapping during the firing, which gives a dark smoky colour to the glaze in places.”

Forrest, who lives in the windswept Outer Hebrides along the west coast of Scotland, has spent years collecting and testing local materials for glazes. She gathers land vegetation such as stinging nettles, Japanese knotweed, lawn grass, meadow flowers, and cereal straw, plus, from the beaches, sea vegetation like kelp. She carefully burns her gatherings to make ash, taking care not to contaminate them. She also gathers and tests stone dust such as gneiss and feldspar, and animal ingredients such as shells and bones.

Forrest keeps meticulous records of her tests, trying each found ingredient singly, and then in mixtures, sometimes using commercial additions like Cornish Stone. Though her work is intensely local, Forrest’s methods can be used anywhere with one’s own indigenous materials. She does, of course, discuss the more often written about wood ash glazes, but happily for us, she does not live in a wooded area, so of necessity she had to turn to other vegetation, thus opening many exciting possibilities for all of us.

This spring, I not only look forward to the emergence of the daffodils in our fields, but, and this is a first, to the return of the stinging nettles and horsetails! Fortunately, Japanese Knotweed has not invaded my gardens yet, but I know where there’s a patch nearby.

Woody Guthrie On Adobe

When Woody Guthrie, the great American folk balladeer who gave us This Land is Your Land, the musician who influenced Bob Dylan, Pete Seeger and many others, discovered adobe during the troubled dust bowl years, he became an evangelist for building with mud. Huddled with his young wife and daughter in a Texas panhandle shack  made of wood lined with old newspapers against the wind, whipped by a blizzard of brown snow, he dreamed of building an adobe house so they would never feel the bitter cold again.

Guthrie first saw adobe while in New Mexico and was intrigued with the longevity of the thick walled mud buildings, the coolness inside in the summer and warmth in the winter. The US government at the time liked adobe too, and explained how to build your own adobe buildings in USDA Bulletin Number 1720. Guthrie obtained a copy of the bulletin (it was 5 cents) and when he read that anyone, with very little skill or money, could build with mud he got very excited. As he sang in Bling Blang:

I’ll grab some mud and you grab some clay

So when it rains it won’t wash away.

We’ll build a house that’ll be so strong,

The winds will sing my baby a song.

He also wrote a novel, House of Earth, in which the protagonist obtains a copy of USDA Bulletin Number 1720 and carries it with him every where, in hopes of one day building a mud house for his family. Though Guthrie wrote and published several books in addition to more than three thousand songs, this was his only novel and it was not published. He hoped it would be made into a movie but that didn’t happen either, and the manuscript languished.

Now, thankfully, with Douglas Brinkley and Johnny Depp (!) as champions, House of Earth is at last available Brinkley and Depp have written a wonderful introduction, putting the book in context. The novel itself stands up well, written in Guthrie’s folksy, passionate style. It’s a love story, a protest against banks and greed and agribusiness. But most of all, at the center, is the promise of adobe. Who would have thought that the iconic Woody Guthrie was a mud man!

A PDF scan of the bulletin is available online for download (warning: the download is slow that I could not even put the link on this page). It is fun and useful to read. The intent seems to be to not only show how to make and use adobe, but to convince the readers of its superiority. Clearly, it convinced Guthrie and through him, Tike Hamlin his character.

I love stuff like this. Don’t you?