Effect of particle size distribution of perlite and organic media on cucumber in hydroponic system.

The selection of a growing medium is one of the most important decisions in the culture of hydroponic crops. In order to select suitable media for hydroponic cucumber (Cucumis sativus L. cv. Negin), experiments were carried out on growing media containing different particle sizes of perlite and organic substrates in a run-to-waste system in greenhouse experiments. Fourteen different growing media were tested in complete randomized block design with four replications. The results showed that addition of cereal straw to sawdust (50:50) resulted in a significant (P0.01) decrease in the mean fruit weight (39%), plant height (30%), and leaf area (79%) of cucumber. The incorporation of poplar chip (75:25) and wheat straw (50:50) into very course grade perlite brought about 65 and 35% decrease in the mean fruit weight of cucumber, respectively. Media containing fine gradeperlite led to a significant (P0.001) increase in mean fruit weight (50%), plant height (25%), and leaf area (70%) of cucumber as compared with media consisting very course-grade perlite.