| Abstract Phalaenopsis and Dendrobium do not grow and flower well with 100% ammonium (NH4-N); and there are detailed studies on the effects of nitrate (NO3-N) and ammonium ratios on the flowering, but no information about accumulation of other nutrients and the effects of ammonium toxicity on orchids. For this reason, two experiments were carried out with orchids: Phalaenopsis ‘Golden Peoker’ and Dendrobium ‘Valentine’. Six months after acclimatization the plants were transplanted to individual plastic vessels and the treatments consisted of five ratios (%) of nitrate / ammonium (0/100, 25/75, 50/50, 75/25, 100/0). The sources of NO3-N and NH4-N were calcium nitrate and ammonium sulfate, respectively. After 12 months treatment, when the plants were... |
