A compost aerator and monitor which has a cylindrical helical screw, preferably with a sharpened first end. The diameter of the cylindrical helix and the tightness of the windings are selected so as, when the screw is inserted into a compost pile, to create a core of compost material that is sufficiently large to be cohesive and representative but not so large that the weight of the core will cause the core to fall from the screw when such screw is withdrawn from the compost pile. Attached to the second end of the screw is a handle with sufficient leverage to enable the screw to be turned rapidly and, consequently, rapidly introduced into a compost pile and to preclude the screw from rotating as the screw is withdrawn from the pile, thereby retaining the core of compost material. Optionally, either a traditional brace or a traditional power drill can replace the simple handle; and a shaft can be inserted between the screw and the handle or the brace. The handle or brace may be either permanently or removably attached to the screw or the shaft, while the power drill is removably connected to the screw or the shaft.