The Effect of Different Concentrations of Nitrogen and Potting Media Composition on the Growth and Quality of Poinsettia (Euphorbia pulcherrima) cv. ‘Noel Red’

Poinsettia (Euphorbia pulcherrima) is one of the most important ornamental pot plants that form colored bracts in short days. The present research carried out to evaluate the effect of different concentrations of nitrogen in nutrient solution (180, 230, 280 and 330 mg L-1) and culture media composition (peat moss and perlite (2:1 v/v ratio) and cocopeat and perlite (2:1 v/v ratio) on some morphological and physiological indices of poinsettia. The experimental was factorial based on a completely randomized design with eight treatments and three replications. Results showed that the nitrogen concentration of 230 mg L-1 with cocopeat and perlite media increased plant height, canopy diameter and nitrogen content of leaf tissue. The concentration of 230 mg L-1 nitrogen also increased fresh weight of stem and root more than other treatments whereas highest stem dry weight resulted with the concentration of 280 mg L-1 nitrogen and cocopeat and perlite media. Using peat moss and perlite mixture with 330 mg L-1 of nitrogen increased chlorophyll a and bract anthocyanin content. Generally, results showed that the application of 230 and 280 mg L-1 nitrogen and cocopeat and perlite (2:1 v/v ratio) medium mixture improve growth indices and quality properties of poinsettia.