Whether you garden for food, beauty or the connection with the wider world that you get from ripping out weeds and conspiring to bring about the early demise of tiny creatures, it’s not just about plants, is it? Perhaps you also long for a few essential things — structures large and small — that can make your garden a more beautiful, more pleasant, more useful place.
You need somewhere to trail clematis or runner beans; a comfortable seat to rest on while admiring the garden’s evolving drama; a place to gather friends and family amid the lush exuberance of this mountain paradise. Or maybe a 12-foot-high, handcrafted replica of mad King Ludwig’s hallucinatory castle (or not).
Sure, you can buy most of these things ready-made (except, perhaps, the castle), but the pleasure of using mostly free, readily available natural materials to create structures that fit your garden perfectly is hard to beat.
I’m talking about mud and sticks and a bit of straw. I mean trellises and fences and arches and even sculpture made from rhododendron, bamboo and all manner of twigs and saplings that someone was cutting down anyway. I mean frog houses (castles, if you like), benches, walls, bread ovens, grills, gazebos, chicken houses and greenhouses fashioned out of mud and a few other ingredients.
Yes, mud! As a gardener, you may not always feel blessed by our region’s beautiful red-clay subsoil, but as a natural builder, I really appreciate it. You know those quaint old cob buildings in Devon, England? Stone foundations, thatched roofs — you know the ones. Well, guess what: The walls are made of mud! And they’ve lasted hundreds of years in a humid, temperate climate that’s much like ours.
That’s right. If care is taken to protect them from the elements (i.e. good foundations, roofs, etc.) cob, adobe and other natural building materials can be appropriate even in our dripping climate. And your yard is a great place to try your hand at something manageable while you learn the ins and outs of building with materials that haven’t traveled the highways and byways of industrial “resource extraction” and “product development.”
The great thing about cob is that it’s easily sculptable. You can make any shape you want, by hand — no need for forms. You can shape it as you build with it wet, or carve it out later when it’s partly (or even completely) dry. It’s a very forgiving material that will set your creativity free. Several books on cob will give you ideas — especially check out Kiko Denzer’s Make Your Own Earthen Oven (Hand Print Press, 2001) and The Hand-Sculpted House by Ianto Evans, et al. (Chelsea Green Publishing, 2002). Becky Bee’s Cob Builder’s Handbook (Groundworks, 1997) has easy-to-to follow instructions and is very woman-friendly.
Cob is a lot like concrete, only not as hard and less rain-resistant — to last outdoors, it needs protection from the weather. In concrete, Portland cement is the binder that holds it all together; but in cob, clay acts as the “glue.” It’s sticky when wet and hard when dry. Both concrete and cob use sand and gravel as aggregates, which give the mixture compressive strength and keep the clay from cracking when it dries out. The addition of wire mesh, rebar and sometimes fiberglass or other fibers gives concrete tensile strength. In cob, we use lots of long strong straw for the same purpose.
You probably have clayey subsoil — one of the major materials used to make cob — right in your own back yard. You could dig out that pond or root cellar you’ve always wanted and get enough clay to build a nice little bench (or barbecue pit, or whatever it was you were dreaming of).
Of course, subsoils vary widely in how much clay, silt and sand they contain. Sometimes what we call “red clay” actually consists of very little clay and a whole lot of silt (which is somewhat slippery but not as sticky as clay). A little silt is OK, but a lot just gets in the way and makes for weak cob.
How do you know if your subsoil has the right stuff? Just do some simple tests (described in any of those books), then make test bricks and see if they crack, or are shedding sand, or break really easily — and adjust your mix accordingly. You will probably have to add either sand or clay (or both if you have lots of silt in your subsoil). But since every subsoil is different, tests are part of the game. And life is just one big experiment, after all, so go ahead and take the plunge — it’s really great fun if you don’t get too stressed out about doing it perfectly the first time. The good news is that lots of mixes will work well — there are many right ways to do this!
If we were in a laboratory situation, dealing with known quantities of pure clay and sand with no pesky silt to interfere, you would aim for 10 to 25 percent clay and 90 to 75 percent sand, adding water and straw “to taste.” Gravel is optional, but you want as much straw as you can get into the mix without it making it too hard to apply. The wetter the batch, the easier it is to both mix and apply; but if the cob is too wet, it will slump. The consistency you’re aiming for falls between very firm bread dough and a somewhat loose cookie dough. (Making cob is a lot like cooking, actually.)
Once you know how, you’ll find it easy to make batch after batch of cob by stomping the ingredients together on a tarp. After the other ingredients are mixed, sprinkle on the straw while stomping it in so it doesn’t clump up. It helps to keep rolling the lump over on the tarp (so the bottom becomes the top) throughout the mixing process. You might want to find someone who’s done it before to show you the process the first time, but playing around with it in a state of “beginner’s mind” is great too. Taking a class is another useful avenue for learning.
When you build with cob, you work each layer into the one below, so it’s all tied together into a monolithic mass. This makes it stronger than structures made of modular units (such as adobe bricks or concrete block), which can crack along the many mortar joints. Adobe is made from the same ingredients as cob and can be used similarly in a lot of situations. And once the bricks are made and dried out in the sun, adobe structures go up more quickly than cob.
Right now, I’m dreaming of a cob bench flanked by two trellises with fragrant, rambling roses climbing over the arched roof — a bench that fits my body, my land and the world at large harmoniously, without causing undue harm. A place where I can lie back and watch the birds and the bees and the wild, green wave that’s threatening to engulf my blueberries. Whoa!
Or maybe I should get back to pulling weeds instead and limit my building ambitions to something even smaller, like a frog house. Maybe one just like King Ludwig’s castle, but only 2 feet high. The foundation could be one big rock…
[Mollie Curry lives and teaches at Earthaven Ecovillage outside Black Mountain. To contact her about natural-building classes, projects or consultations, call 669-7007 or visit the www.earthavenlearningcenter.org.]