I did another test of soil temperature, this one while the “Summer in March” heatwave had just ended. The pitchfork is an inch-and-a-half deeper into the soil than last time, showing that the earth continues to “defrost.”

As you can see, the soil temperature is five degrees cooler than it was the last time I measured it.

I’m guessing the seeming paradox of lower frost line and lower soil temperature is resolved when I consider that (a) a temperature above freezing will cause the earth to defrost, and (b) soil temperature, at least at the depth of a squash mound, probably fluctuates a lot more than I imagined. Maybe I should do some readings at different times of the same day to prove this to myself.

Meanwhile, it’s fascinating to think of the frost line sinking deeper and deeper into the earth, finally disappearing at the depth that the winter cold could never penetrate. Then, whatever’s under there wakes up, and starts heading to the surface….

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