Carnations planted in November, 1965, were watered when soil moisture suction reached 0.04 bar, 0.6 bar and 10K ohms resistance (ca 20—50 bars), the latter measured with gypsum blocks. Yield was found to be highest for the 0.04 bar treatment. Mean grade was consistently higher for this treatment than the other 2 treatments throughout the flowering period. The results were mainly due to increased side shoots and longer internode lengths of cut flowers grown at suctions below 0.04 bar. Keeping life was reduced, but dye uptake was enhanced by growing carnations with frequent irrigations. Consumptive water use increased from 120.9 cm for the 10K ohm treatment to 184.7 cm for the 0.04 bar treatment, exceeding the water equivalent of solar radiation outside the greenhouse. However, there was no significant effect on water required per cut flower or on efficiency, whether the latter was based on total yield or dry weight. It was concluded that maximum production would occur where soil moisture stress is zero and internal plant stress is as close to zero as possible, provided other factors were favorable.