The yield and quality of lettuce crop, grown in different growing media

Abstract

In this study four different growing media were used to grow lettuce and the difference in yield was assessed. The growing media studied were coco coir, peat potting substrate mixted with soil, peat potting substrate premixed with perlite, and soil. The possible leaching of nitrates from the growing media was also assessed, to determine the difference in the nitrates leached between the different growing media. The lettuce sap nitrate and heavy metal content, were also assessed so as to determine any health and safety implications. It was shown that lettuce crops grown in coco coir have the highest yield in terms of mass (294.2 g/plant). Lettuce grown in a peat potting substrate mixed with perlite, and a peat potting substrate mixed with soil, showed a lower mass than when grown in coco coir. The lettuce grown in soil has shown the lowest mass (108.8g/plant) of all the growing media. Lettuce grown in coco coir had the greatest yield in terms of growth. Lettuce grown in peat potting substrate mixed with perlite, and peat potting substrate mixed with soil, showed lower growth than when grown in coco coir. The lowest growth was seen in lettuce grown in soil. With regards to nitrate leaching, the lowest amount of nitrates leached were found when grown in the peat potting substrate mixed with soil. Regarding the lettuce sap nitrate, lettuce grown in peat potting substrate mixed with soil had the lowest sap nitrate (2552.8 mg/kg). Heavy metal content for all the growing media, were found to be below the safe threshold for Cu, Mn, Fe and Zn, however the level of Pb was found to be above the safe threshold.