Evaluation of the effect of nitrate to ammonium ratio and substrate on the quality of ‎Phalaenopsis orchid ‎

The experiment was performed as a completely randomized factorial with three replications. Experimental treatments included Kobe and Memphis cultivars, four levels of nitrogen and three types of substrates. Nitrogen sources in the ratio of calcium nitrate to ammonium nitrate were 90:10, 75:25, 50:50 and 25:75, respectively. Culture media include; 1- Compost of coniferous bark (mainly pine) in the ratio of 2 parts of bark and one part of perlite, 2- Two parts of plantain leaf compost and one part of perlite, 3-  Peat moss with a ratio of 2 parts peat and one part perlite (as a control). The results showed that in the ratio of 75:25 calcium nitrate to ammonium nitrate, the highest amount of calcium, fresh and dry weight of aerial and underground organs and also, the longest post harvesting was obtained for 12.62 days. In the substrate with a combination of two parts of peat and one part of perlite, the highest wet and dry weight of shoots were obtained that it was statistically flush with the plane leaf. Overall, the results showed that the ratio of ammonium for feeding orchids in both cultivars should not be more than 25%. Two parts plane leaf compost to one part of a mixture with an aeration material such as perlite can be a good substrate for orchid production.