Typically walk-behind trench diggers do not have the horsepower or torque for trenching frozen ground. Ride-on trenchers are the standard for frost-covered ground. If it is a light frost and the soil underneath is soft, a walk-behind trencher with a pointed carbide blade will be able to break up the frost. However, a walk-behind trencher may take a long time and be insufficient. See the operator’s manual and manufacturer specifications for digging depth limits.