Soil Temperatures Are Increasing
I know it may be hard to believe with as cold as it has been this winter but soil temperatures have increased in the last month. At the beginning of February soil temperatures at the 2, 4 and 8 inch depts. were 25 to 26 degrees at the Southern Research and Outreach Center at Waseca (SROC.) Late last week the soil temperatures had increased to 29 to 30 degrees. In addition the frost depth is at 18 inches where the beginning of February the frost depth was 19 inches.
How is that possible when one week ago the temperature at the SROC was 29 degrees below zero, the coldest ever recorded in March? This winter we are seeing just how good snow is as an insulator. The deep snow is preventing the really cold air from penetrating the soil. In addition the soil temperatures are warmer at lower depths. In the last month the frozen soil thawed from the bottom of the frost layer. Typically we assume the soil thaws in the spring from the top after the snow melts!