No single sensor modality will solve the problem of detecting small, buried objects in soil in the presence of typical clutter. Techniques involving fusion of data from multiple sensors can improve detection statistics. At the next level of complexity is multi-modal sensing in which an excitation with one modality is detected by another. Here we consider one such example, microwave heating of the soil followed by infrared imaging. The technique promises to produce signatures of buried objects which have contrast with respect to the surrounding soil in (1) absorption at the microwave frequency resulting in a change in the amount of energy absorbed, (2) dielectric constant resulting in alteration of the field distribution in the soil, or (3) thermal properties resulting in changes in the heat distribution. Indirect detection may be possible, through changes in the microwave or thermal properties of the soil caused by disturbance during placement of the object, or caused by changes in the soil properties resulting from alterations in water content caused by the object. We discuss wavelength selection, expected sensitivity, and techniques for enhancement of the signal, as well as overall system requirements, and will show some preliminary results.