Boron application to potato in southern Idaho is often made to sandy soils as "insurance" with little evidence for a critical soil value. These haphazard applications could result in either deficiencies or toxicities under current practices. A site with sandy soil was selected near Blackfoot Idaho to which 0, 2.2 and 4.4 kg/ha B were applied to the soil at two times, emergence and just before bulking. In addition, foliar application just before bulking was made at 0.22 kg/ha B as a separate treatment. Boron concentrations in petiole and tuber were assessed as well as total and graded yields measured. There was an economically significant improvement in yield from the midseason foliar application. We will report petiole and tuber concentrations of boron from these field treatments. Further testing of the midseason application at more intermediate application rates are currently underway.