Effect of planting density and nitrogen levels on growth and flower production of calendula (Calendula officinalis L.).

The present investigation was undertaken with the object to standardise the optimum spacing and nitrogen application rate of Calendula officinalis L. The field trial was conducted with four planting densities viz., 30 cm × 20 cm, 30 cm × 30 cm, 45 cm × 30 cm and 45 cm × 45 cm and four levels of nitrogen viz., 0 kg N/ha, 60 kg N/ha, 100 kg N/ha and 140 kg N/ha. The experimental findings revealed that growth parameters like number of leaves, number of branches and leaf area per plant were maximum at lowest planting density (45 cm × 45 cm) and 100 kg N/ha, whereas the height of the plant was maximum at 30 cm × 30 cm and 100 kg N/ha. Early flower bud initiation was observed at a spacing of 30 cm × 20 cm and when nitrogen was not applied. Maximum flower diameter and average weight of individual cut flower were obtained at a planting density 45 × 45 cm with 100 kg N/ha. Cut flower and loose flower yield per plant were maximum when plants were spaced at 45 cm × 45 cm and supplied with 100 kg N/ha, whereas yield per unit area was more at highest planting density (30 cm × 20 cm) along with 100 kg/ha nitrogen.