Mud Season

In my south-central Pennsylvania garden, winter transitions into a long, gentle spring that is the most delightful of seasons. But in my Maine garden, the only way to get from winter to spring is to pass through the least delightful of seasons – mud season.

Mud season is created when moisture from snow melt (often accompanied by spring rains) cannot drain away because the ground is still frozen. At first, all this moisture forms large puddles. Then, as the ground begins to thaw, it absorbs moisture, softens and turns to mud. As my neighbors and I drive in and out on our dirt road, the soft ground forms muddy ruts.

Because the ground thaws from the top down, the mud and ruts keep getting deeper and deeper as the thaw continues. I’ve seen a number of estimates of how deep the ground freezes in my part of Maine. One published frost map puts the average frost depth for my area at 36-40”; local building codes (which are designed to deal with worst case conditions) put it at about 4-5’. Once the mud gets deeper than the clearance between the car’s undercarriage and the ground, my road is no longer passable. In the worst mud season I can remember, I couldn’t drive in and out for two weeks; I parked my car on the paved road a quarter mile from my house and slogged through the mud wearing tall rubber boots and a backpack for carrying things. In the best years, while the road may get a bit dicey, it’s never completely impassable.

How bad the mud gets depends on a number of factors.  First is how severe and how prolonged the cold has been in the winter; the colder the winter, the deeper the frost. A second factor is how deep the snow pack is.  In the garden, a deep snow pack provides insulation that lessens the freezing. But the dirt road is kept plowed, so it doesn’t benefit from that protection; here a deep snow pack just means more moisture that has to go somewhere during the thaw. A third important factor is the amount of spring rain; if snow melt is accompanied by heavy rains, the mud will be worse. A final factor is how warm it gets and how quickly the thaw occurs; a faster thaw means fewer days of severe mud. The worst mud seasons are characterized by cold, snowy winters, with heavy rains during the spring thaw, and weeks of temperatures in the forties and low fifties.

Despite our yearly struggles with mud, though, my neighbors and I are lucky because the geology of our area is characterized by glacial sand that is the ultimate “well draining soil.” Once the deepest frost thaws, the moisture drains away and the mud disappears remarkably quickly. For those who live in areas with clay soils, mud can hang on for a long time. But for us mud vanishes in a small miracle each spring. I can slog out through the mud in the morning and return before lunch to a smooth, sandy road that shows no sign of the muddy ruts that were such a problem just hours earlier.

Snow and rain are important to the ecology of Maine, but I’ve never met a Mainer who had anything good to say about mud season. This year, I hope to miss the whole thing. When I was in Maine last week, mud season was just beginning, with much of the moisture still bound up in the snow pack and the ruts in the dirt road only inches deep. I’m hoping that by the time I return in a few weeks, the miracle thaw will have already occurred and mud season will be over.