Friday, December 28, 2012

Something there is that doesn't love a wall

Do you remember that Robert Frost poem about the stone wall. Mending Wall, I think it is.  I remember that one line.  'Something there is that doesn't love a wall'.

Out here on the farm there are a lot of things that don’t like stone walls but the biggest culprit is water.

Freezing water.

Over the years I’ve lost track of exactly when the greens die in the witner but I’m guessing it’s a lot like the stone walls.

And for pretty much the same reason.

What’s that?

Walls, buildings, greens.  Freezing water can do them all in.

For buildings, like houses or barns, you need to put its feet (footers) below the frost line  (that’s the depth where the ground freezes) so a frost doesn’t pick up the building and move it.

I think the building code here in Northern Virginia is something like 2.5 feet.  You have to put the footers down at least 2.5 feet so the frost can’t get below the building.

There’s all sorts of charts giving the deepest frost line for different  parts of the country but basically you want to put the footers or crawl space or basement so it goes down below the deepest frost during the coldest part of the winter.

That way the building isn’t lifted up when the ground freezes. (when the water in the soil freezes it expands, gets larger, and lifts everything on top of it (including houses) up.

If a building isn’t built with footers that go below the frost line the dirt under the house freezes and the house is lifted. 

I don’t think Robert Frost’s walls were built with footers  (we did, though, put a footer  under the one we built around our house).  Therefore, every year the wall between Mr. Frost’s land and his neighbors was lifted up and dropped down, causing the stones to move up and fall down.

Imagine what happens to a building if its lifted up in the air, even only a little bit. (walls cracking, pipes breaking, and a lot, lot worse).

However,  if the footers go below the frost line, the freezing water in the soil doesn’t have the ability to lift.

With a plant its sort of similar.  The frost might not lift the lettuce greens but if the roots freeze the water in the roots expands, rupturing the cells in the roots, killing the plant.

If you’ve been out to our farm this winter and looked over where we’ve planted next season’s garlic you’ll see that its covered with straw.

We do that for a similar reason.

The straw helps prevent the soil underneath from freezing solid.  If it doesn’t freeze solid it can’t heave the garlic out of the soil  (just like with a house).

We have a problem this year in that some of our garlic isn’t covered with straw.  Our neighbor, who we get the straw from, ran out and I haven’t been able to find another source.

Hopefully it won’t get that cold until I do.
In the foreground is the garlic covered with hay.  In the back is the garlic without.  You can see how the closer garlic is poking up through the hay.  Because the ground is so wet I haven't been over to the garlic in the back to see if the frost has damaged it  ('heaved' it out of the ground, breaking the roots.

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