Abstract
With the rising costs and the declining availability of peat, it is necessary to look for alternative materials to be used as growth media. Clay soil and composted rice straw are cheap and readily available candidates once there pH is adjusted. In the current study, growth of Gardenia jasminoides Ellis was compared in different growth substrates (peat moss, clay and composted rice straw) treated with ferrous sulfate (200 ml/pot) at various time intervals (0, 10, 20 and 30 days). Peat moss produced the best vegetative and flowering growth characteristics along with the highest leaf content of chlorophylls a & b, N, K and Mn in both seasons. Rice straw-grown plants showed moderate growth proving superior to clay-grown ones in terms of plant height, branch number, internode number and length, shoot fresh and dry weights, flower diameter, leaf content of carotenoids, P and Cu. Using of ferrous sulfate enhanced the performance of both rice straw and clay. This effect was clear as the frequency of the application was increased and the most frequent application (10-day interval) produced generally the best results. Composted rice straw and clay soil treated with ferrous sulphate at 10-day interval were comparable to peat moss regarding their effect on growth and flowering of gardenia plants.