Analysis of soil and plant tissue for boron (B) is routine, but more information is needed to clarify the interpretations of test results as a basis for B fertilization of potato (Solarium tuberosumL.). Experiments were conducted in nutrient cultures and in the field to relate the utilization of B by potato plants to visual symptoms of deficiency and toxicity. Without added B the nutrient cultures produced B‐deficient potato plants, but the field plots with 0.3 to 0.4 mg of hot water soluble B/kg of soil did not. Plant shoots from nutrient cultures had a minimum of 13 mg B/kg as compared with plants in field plots with 30 mg B/kg in vines. Concentrations to 50 mg B/kg of dry matter were obtained in plant shoots from nutrient cultures with 1 mg B/L added and in field‐grown plants fertilized with 2.2 kg B/ha. Toxicity to B appeared or was eminent from either adding 3 mg B/L or more to nutrient solutions or 4.5 kg B/ha or more to the field plots. These results suggest the feasibility of developing critical nutrient (sufficiency) ranges for B in plant shoots and vines.