Small-scale greenhouse growers commonly use perlite as substrate in the Dutch bucket hydroponic production of vine crops such as tomatoes. However, perlite is prone to an excessive nutrient solution leaching primarily due to its free-draining and low water holding capacity properties. Alternative organic substrate to perlite is needed for a sustainable hydroponic production of these fruiting vegetables in the Dutch bucket system. This study thus evaluated the growth and yield performance of two tomato cultivars (BHN 589 and Geronimo) in five substrates (clay pebbles, loose rockwool, perlite, coco coir, and Lensli) in a randomized complete block design with three replications inside a polyethylene film greenhouse from February to July 2024. Results showed no significant effects of the interaction of substrates and cultivars on all the measured growth and yield traits. Averaged over the two cultivars, the substrates tested significantly influenced the total yield ranging from 338 to 464 Mg/ha and marketable yield ranging from 328 to 445 Mg/ha. More specifically, Lensli increased marketable yields by 15, 31, and 36% than those of coco coir, perlite, and clay pebbles, respectively. These increases are primarily due to a significant increase in the number of marketable fruit per plant (19%) and average marketable fruit weight (10%). Lensli also increased leaf area index by 44 and 60% than those of perlite and clay pebbles, respectively. Based on these results, Lensli, a blend of fine Baltic and superfine black peat, is proving to be a promising organic alternative substrate for tomato production in the Dutch bucket hydroponic system.
