Sustainable hydroponics: Boosting red lettuce growth with photosynthetic bacteria and optimal transplanting

Abstract

Red lettuce growth under hydroponic conditions was significantly influenced by transplanting age, whereas the application of photosynthetic bacteria (PSB) showed no notable effects. Transplanting at 16 days after sowing produced the tallest plants, with an average height of 10.59 cm, significantly higher than those transplanted at 10 and 13 days. In contrast, the highest number of leaves was recorded in plants transplanted at 10 days, averaging 12.08 leaves, which was significantly greater than those transplanted at 13 and 16 days. Leaf width did not differ significantly across transplanting ages, although 10-day transplants showed slightly wider leaves. PSB application at different times (0, 3, 7, and 10 days after planting) did not significantly impact any measured growth parameters, including plant height, leaf width, or number of leaves. Similarly, no significant interaction effects were found between transplanting age and PSB application timing, suggesting that transplanting age alone independently determined red lettuce performance. These findings highlight that optimal transplanting age is a critical factor for enhancing either plant height or leaf production in hydroponic red lettuce, while PSB application under the tested conditions did not contribute to measurable improvements. The results suggest prioritizing transplanting schedule over microbial enhancement for efficient and sustainable hydroponic cultivation of red lettuce.