Field experiments were conducted in summer 1992 on the Central Experimental Farm, Ottawa (45°22'N, 75°43'W) to determine whether a stem infusion technique developed for maize under controlled conditions was applicable to field‐grown maize and to evaluate whether providing sucrose in solution at silking via stem infusion altered plant source‐sink relationships sufficiently to increase kernel set. The higher and more variable evaporative demand and more difficult installation under field conditions dictated modifications to the stem infusion apparatus to prevent leakage and to facilitate assembly prior to field set‐up. A range of several field parameters were tested to identify conditions that would maximize infusion of sucrose solution: raising the syringe barrel height increased the volume of solution uptake; the largest amount of sucrose was taken up using a concentration of 150 g sucrose L‐1, and consecutive multiple infusions of the same plant increased solution uptake. Solution uptake was found to be greatest in the first 24 h of infusion. Leaf soluble carbohydrate and starch concentrations and ear leaf photosynthesis were not changed by sucrose infusion. Sucrose solution infused at silking appeared to increase kernel set in one of the experimental hybrids.