This study investigates the influence of various fertilizers and substrates on the leaf development of Lactuca sativa (lettuce) grown under hydroponic conditions. A comparative analysis was conducted using four substrates (vermiculite, perlite, coco coir, and rockwool) and six fertilizer treatments: mineral salts, humic acid, humic acid + mineral salts, microalgae, microalgae + mineral salts. The results indicate significant variations in leaf number depending on the combination of substrate and fertilizer, with rockwool and microalgae + mineral salts showing the highest efficacy.