Fresh market tomato production has a high demand for potassium (K) and may be responsive to the micronutrient boron (B). An excellent Iowa yield of 1,000 cwt/acre will remove 240 lb of K20/acre in the fruit alone. Thus, growers apply high rates of K20 fertilizer to achieve top yields and quality. Iowa research and soil surveys over the years have shown no need for B additions for corn,soybean, and alfalfa production (Dr. Randy Killorn, personal communication). However, our vegetable K research trials have shown low B leaf levels early in the growing season, 27 to 42 ppm. Tomato leaf sufficiency ranges vary from 20 to 75 ppm, depending on the region where the research was conducted and the crop stage of growth at the time of sampling.