A mass balance nutrient management approach was used in controlled environment studies, to determine an appropriate nutrient solution replenishment regime for the growth of sweetpotato in nutrient film technique (NFT). Four stem cuttings (15-cm long) were planted into each of three gray PVC-1 (0.15×0.15×1.2 m) troughs in a walk-in growth chamber under a 14/10 h photoperiod, 28/22°C and 70% relative humidity. Photosynthetic photon flux at canopy level averaged 450-μmol m−2 s−1. Plants were grown with a modified half-Hoagland starter solution with an extra 3 mM of N for the first 4–6 weeks to accelerate vegetative growth, after which three refill solutions containing 1.5 (A), 4.5 (B), 0.75 (C), or 3 (A), 4.5 (B), and 6 (C) mM NO3−1-N and K, respectively, were used once per week until harvest. The level of N and K in the refill solutions did not significantly influence the number of storage roots produced. Total fresh and dry biomass was significantly greater among plants replenished with the refill solution containing 4.5 mM N and K, respectively. Edible fresh and dry biomass was also greater for plants receiving the refill solution containing 4.5 mM N and K than that for plants replenished with the refill solution containing 0.75/6.0 mM N/K, and similar to that of plants receiving the refill solution containing 1.5/3.0 mM N/K. Harvest index was significantly lower among plants replenished with the refill solution containing 4.5 mM N and K, respectively. Leaf analyses data indicated that sufficiency levels of N, P and K were maintained in plants replenished the refill solution containing 4.5 mM N and K, respectively, but was reduced among plants replenished with the refill solution containing 0.75/6.0 mM N/K. Thus in terms of biomass production and maintaining nutrient levels within the plant, either the refill solution containing 4.5 mM N and K, respectively, or the refill solution containing 1.5/3.0 mM N/K can be used for replenishment.