This experiment was carried out to study on the effect of different NO₃ ¯:NH₄ ⁺ ratios on macronutrient content and growth of two cut gerbera (Gerbera jamesonii Bolus ex Hooker f.) cultivars in an open hydroponic system. The plants were nourished with different NO₃¯:NH₄⁺ ratios as 100:0, 80:20, 60:40, and 40:60. The application of NO₃^- and NH₄ ⁺ at ratio 40:60 caused a reduction in flower height, stem and disk diameter, number of flowers, inflorescence fresh and dry weight, and vase life. Results indicated that N, P and NH₄ ⁺ concentrations were enhanced in leaves of gerbera cultivars by increase of NH₄ ⁺ ratio, whereas K, Ca, Mg, and nitrate were decreased. As compared to ‘Double Dutch’, the ‘Stanza’ cultivar could uptake more of N, P, and Mg. Inversely, ‘Double Dutch’ was able to uptake more of K and Ca than ‘Stanza’. Defined optimal ratio of NO₃¯:NH₄ ⁺ 80:20 could be used for gerbera production in vegetative and reproductive stages.