Well, first we had to transition the soil from grass and scrub land to agricultural soil. Having already learned how vulnerable this soil is to compaction after tillage, (and having this bent anyway) we opted for hand tool work. That is more or less as arduous as it sounds. After hacking grooves among the roots, rocks, and grass clumps to receive our potato chunks, we then had only to dislodge the rest of the turf and cut through more roots to get enough loose material for hilling once the sprouts emerged. At every stage we hauled out as many rocks as we had time for. I am convinced that we harvested more calories each year than we expended…but not by a whole lot! After four years of this, we had converted four 12 foot by 100 foot areas to what might pass for agricultural soil, and we then could ascertain what kind of condition it was in for growing potatoes once every four years (we selected a four-year crop rotation scheme for that system).
The answer is that it kind of stinks. Sometimes literally, because water does not drain out of some of the soil very readily, it turns out, rendering conditions anaerobic (lacking oxygen). Microbes that operate in anaerobic conditions tend to produce compounds humans find obnoxious. Think drain pipes, the bottom of your compost pail after it’s sat for a week, water from a vase with an old bouquet of daisies in it…you get the picture.
Plant roots generally don’t fare well in anaerobic conditions, with the exception of species adapted for swamps. Many tubers are especially sensitive to this, since their high energy content make them likely targets for fungal and bacterial invaders anyway, and when anaerobia stresses them further they are very likely to succumb. So our potatoes tended to set their tubers near the soil surface in our hilled rows, because that’s the only place the roots weren’t getting too soggy. Yields were mediocre, many tubers were greened by the sunlight because of that crowding to the surface. Not to mention rocks. Lots and lots of rocks. Bleh.
But I have a stubborn streak, we are committed to providing our food needs from this land (and we like potatoes), we had gotten this far, there was no guarantee we’d find better soil elsewhere (much of our soil is undergirded by naturally compacted layers), and for the aforementioned reasons it was still the right place. So the point was not to put up with mediocre results, nor was it to throw up our hands; it was to transform the soil from crummy potato ground to excellent potato ground.
My first idea was that the soil just needed time to get organic matter deeper into its strata. We’d work with cover crops, compost, and mulches and assume some physical mixing of soil to incorporate the residues of these materials despite our minimum-tillage approach because you can’t dig potatoes without some soil mixing. But I noticed that some areas were worse than others. I realized after a heavy rain when I looked at the puddling patterns that my rows were not uniformly just-barely-off-contour as I had intended because of topographic variation. Never one to shrink from the heavy work when it comes to establishing a long-term food production system, I gamely excavated soil from between the rows in the worst of the patches, checking soil levels and slope to ensure adequate surface drainage. In some areas I had to remove almost 8 inches of soil!
And that is when I first found it. Clay. Dense, yellowish clay, down about 6 inches from the surface, nearly free of large rocks, smelling mildly anaerobic. It was so dense it almost squeaked when I plunged in the mattock, and it came out in hunks that refused to crumble. It could be wadded and molded at will, and had few roots in it. This was profoundly different from any other place I had dug on our farm, and struck me as unusual for the Shenandoah Valley in general, which usually has orange or red clay (and plenty of it…our flinty chert-based soils are an oddity in the area and no one seems jealous). I stuck some in a Ziploc and took it show my neighbor Samuel (now deceased), who had lived here over thirty years and knows more geology than I. He was not terribly impressed, so I didn’t do anything more with it, but I kept wondering.
Then this winter we installed a new garden fence, which implied fence posts, which implied holes in the ground. The fence’s path took me near that same area, and—sure enough—up out of those holes came wads of that dense, yellowish-tan clay—smooth and relatively pure. Tamping the soil around those posts, my tamper slapped and smacked and smooshed, leaving neat impressions of itself in the surface, as if I were in some avant-guarde (sp?) ceramics studio discovering new techniques. Yes, pottery was on my mind.
I’ve had interest and some limited experience in pottery/ceramics in my past, and never did get enough of it. One of my recurring fantasies has been to discover a good clay dig on our place and find we could make pots from it. Could there be a more fitting cottage industry for folks who endeavor to grow their life from the soil? But as I was installing the fence I didn’t save aside any more hunks, I just tamped it back in place around the posts. However, I often took notice of those yellowish clods of soil remaining on the surface, and I kept wondering.
This spring I finally got a trellis installed for the new row of Triple Crown blackberries that bisects two of the root patch sections. More posts, and more clay than ever. This time I was impressed that I couldn’t even chunk it up in the hole to extract it; I had to plunge with the post spade all around the perimeter of the next layer I wanted to remove, then pry it loose en masse, such that when I lifted the results I had relatively neat pucks of clay six inches across, three inches thick, and just as heavy as you could want. This time I couldn’t resist. I pulled six of the cleanest ones aside, bagging four in Ziplocs to stash with the old pottery stuff in the garage. Two I brought down to the work room. I had an idea.
Mondays are home school days, sort of. We practice Unschooling, so education happens all the time for us, but when we have a special project or just as way of making time for the workbooks or whatever, Mondays are a good excuse to concentrate or “waste time” on something not obviously productive. I thought the girls might like to help me explore this clay a little.
We processed the two hunks two different ways. One of them we chunked up and kneaded water into, picking out the few stones, aiming for a moldable clay. It got wetter than we meant, because it was too hard to mix by hand until we’d added that much. So we got out the old plaster bowls from the pottery stuff and let the sticky mass sit in one to wick out moisture.
While waiting, we cut up the other one that had been soaking in water into small pieces, then added enough water to make a slurry. We mixed and mixed and mixed this one with our hands until it was smooth. Then we forced the slurry through a canning sieve, which netted us a small handful of sharp little stones and some organic debris in the sieve, and a beautiful mass of “slip” (very wet clay gel). The slip we deposited in another of the plaster bowls for drying, sliding it up around the sides to coat then plaster and take advantage of the larger surface area, then recoating every time it got to looking dry enough.
By evening the first batch was dry enough to work with, so while Janelle took a little time to herself upstairs (much needed), the girls and I set up a table in the work room and went at it, rolling out snakes and molding figures. I made a coil jar that I liked well enough to set out to dry. We found the clay smooth and workable at the studio level, and I thought it resembled the stoneware clays I’ve worked with in the past, though I don’t know whether clay can be judged by feel.
The older two girls and I came up with things we wanted to keep around for the time being, but now we had the puzzle to figure out: Will it fire? We have no idea what temperature it would require to vitrify or if it ever could. Would it be a low grade terra cotta or a high-fire stoneware suitable for water-tight vessels or even wood firing?
That’s our next step. We must know. We’ve got a little crafter’s kiln in the garage that would be perfectly suitable for testing it out, and I think I get the idea of the method. We just need to find and buy a missing part, pick up some indicator cones of various temperatures, and we’re in business.
Or, rather, we have one more piece of information to tell us whether there is any kind of chance that we’re in business.
Of course we still would not have dealt with the fact that most of the clay is probably under our potato patch.
P.S. I think we’ve figured out the how to grow good potatoes in that soil, but that’s a story for another day.