The efficient design and construction of solar-energy air-heating collectors are critical to the overall performance of the distributed (indirect mode) and mixed-mode designs of either active or passive solar-energy crop dryers. A review of the various designs and the performance evaluation technique of flat-plate solar-energy air-heating collectors for low temperature (i.e. temperature elevations between 10 degrees C-35 degrees C above ambient) solar-energy crop drying applications are presented. The appropriateness of each design and the component materials selection guidelines are highlighted.