Bio-Organic Hydroponic Cultivation of Curly Greens Leaf Lettuce ( <i>Lactuca Sativa</i> var. <i>Crispa</i> ‘Grand Rapids’)

Abstract Hydroponic cultivation, a climate-smart technology that complements conventional agriculture, is increasingly recognised as a key strategy for enhancing food security, optimising resource efficiency and reducing environmental impacts. Over the years, several high-value crops, such as leafy vegetables and herbs, have been successfully grown in hydroponic systems on a commercial level, with limited exploration of their potential for healthier organic cultivation. This study has effectively described the effects of indigenous bio-organic nutrient solutions on the growth and development of curly green leaf lettuce ( Lactuca sativa var. crispa ‘Grand Rapids’) grown under hydroponic cultivation. Five nutrient solution treatments using combinations of inorganic and bio-organic fertilisers namely, pure inorganic nutrient solution, pure vermitea, inorganic-vermitea, indigenous microorganisms (IMO)-vermitea, and fish amino acid (FAA)-vermitea were used. The pure vermitea nutrient solution showed the greatest improvements in plant growth, including plant height, number of leaves, leaf width, leaf length, shoot fresh weight, shoot dry weight, and root dry weight at harvest. The combination of vermitea with inorganic nutrient solution exhibited higher plant growth parameters compared to those grown using combinations of IMO and FAA, indicating the possible stunted growth of lettuce due to several factors, including the inhibitory effects of the abundant presence of microorganisms in a static solution culture. Our data revealed that pure vermitea organic nutrient solution promoted strong lettuce growth, comparable to plants grown with commercially available inorganic nutrient solution. This indicates that locally available organic nutrients can serve as a potentially effective nutrient solution for organic hydroponics, promoting healthier crop cultivation while being less harmful to the environment.