Comparisons (of the first harmonic) between exact and two approximate analytical solutions to the one-dimensional heat conduction equation for an inhomogeneous soil show that the approximate analytical solutions are potentially more useful for profiles of soil thermal properties that exhibit positive or zero concavity than for those that exhibit negative concavity. Comparisons between the two approximate analytical solutions also suggest that one solution provides a much easier method for estimating profiles of soil thermal properties from soil temperature profiles than does the other. A brief summary of three analytical solutions to the one-dimensional heat conduction equation is also given. Furthermore, some of these extent analytical solutions are unique to the present study and employ relatively simple and easily implemented algorithms for their evaluation. For many applications involving periodic variations in soil temperature, these algorithms are likely to provide more realistic results than can be obtained by assuming homogeneous soil properties with their associated “exponentially decaying” solution for soil temperatures. It is further suggested that the solutions presented in this work could be used to verify more complex numerical models of soil heat flow.