This study was carried out to investigate the effect of potassium concentrations in fertigation solution on growth and development of nutrient deficiency symptoms of leaf perilla (Perilla frutesens). The nutrient concentrations in above ground plant tissue, petiole sap and soil solution of root media were also determined. Potassium deficiency symptoms developed in older leaves with marginal necrosis. The brown areas on the lower leaves enlarged rapidly and the margins became scorched. Elevation of K concentrations in the fertigation solution up to 8 mM increased the crop growth in leaf length, stem thickness, and fresh and dry matter production of above ground plant tissue. However, that decreased the chlorophyll contents. The 8.0 mM K treatment which showed the greatest growth had 5.01 g in dry weight and 2.76% in K content of above ground plant tissue, suggesting that maintaining K content higher than 1.7% is necessary for good growth of Perilla frutesens. The K concentrations in petiole sap and soil solution of 8.0 mM treatment were $12,289mg{cdot}kg^{-1};and;11.65mg{cdot}L^{-1}$, respectively. These indicated that K fertilization to maintain higher than $8,700mg{cdot}kg^{-1}$ in petiole sap and $4.5mg{cdot}L^{-1}$ in soil solution are necessary to ensure good crop growth.