COCONUT COIR SYNERGISM WITH PLANT RESIDUES AUGMENTS THE POTTING MEDIA QUALITY AND LETTUCE GROWTH

Abstract

Commercial potting mixes often contain coconut coir as an alternative of peat. With the aim to find an economical and efficient potting medium, some plant residues, viz., coconut coir (CNC), date palm coir (DPC), rice hulls (RH), saw-dust (SD) and corn cobs (CC) alone as well as combined with CNC (1:1), were evaluated for the growth and nutrient accumulation of lettuce. Morphological plant parameters indicated that CNC+RH and CNC+CC performed better than all the sole and other combined potting media. Potting mix containing CNC had higher nitrogen content and rendered greater leaf area index of lettuce plants. Regarding chemical parameters, pH of all potting mixes was almost neutral; CNC+RH potting mix rendered the highest nutrient contents in lettuce leaves if compared with rest of the substrates. These results reflect that largely available and cheaper plant residues could be exploited to prepare alter- native potting media in combination with expensive coconut coir substrate.