But in the spring, small boulders appear as if by magic in the middle of the fields. It looks as if a bear has come along and pried chunks of granite from the ground. Maybe cranky from the long sleep? Perhaps searching for grubs? What if it's a mysterious ursine ritual feat of strength? And, not for nothing, they've got a problem with you people!
But no, this is "frost heave" at work. A prosaic name for the kind of amazing thing that happens with sub-zero temperatures, wet clay soil, and rocks.
In clay soil, water tends to pool. A small bit water pooling between a rock and the soil around it will expand and widen the gap between rock and dirt. A cycle of thawing and freezing allows more water in, which widens the gap farther and farther until there is enough volume for ice to pop the rock (this one pictured about 45 pounds of lower-back discomfort) clean out of the ground.
The field doesn't care where the stone lands. Grass grows up –– and the next thing you know, you're clanking into the chunk of granite with some surprisingly delicate part of a large and expensive piece of mowing machinery.
Smart money says to relocate the thing before the grass hides it.
Call it rock safari and make it yearly event (along with the annual Burning of the Burdock and Spot the Porcupine) and you have yourself a new neural pathway.
Ironically, this activity strongly resembles what we called "rock picking" when some of us were young farming types. Everything old is new again!
But there's a limit. Seems like frost heaving tops out at around 50 pounds. Or perhaps that's just around the same point where human effort runs into a wall. It's simply hard to hoist anything heavier and stagger it to a better spot by hand.
Only a couple of frost-heaved (frost-hove?) rocks appeared over this past winter, but the rockiness of the Farm seems nearly endless. At least four outcroppings of pink granite lurk around Base Camp, just waiting to catch a blade on the weed-whacker or trip a distracted walker.
After attending to the thrilling culvert and ditch issues, we still had a few days custody of the equipment. Rock safari went into a higher gear: we cleared the rocky path to both old orchards, we dug up inconvenient boulders, we nudged large stones into more desirable spots.