Effects of biochar in the seedling growth of lamb’s lettuce

Biochar, used as a soil conditioner, is carbon-rich solid material that emerges by subjecting raw materials to high heat in an oxygen-limited or oxygen-free environment. Building upon the positive effects of biochar on soil fertility and plant development, this study aimed to determine the effects of adding biochar to the seedling growing medium on the quality of lamb’s lettuce seedlings. Biochar (BC) was mixed with peat (P) in volumetric ratios of 0% (0%BC+100%P, control), 5% (5%BC+95%P), 10% (10%BC+90%P), and 20% (20%BC+80%P), and the prepared mixture was moistened and filled into 45-cell foam trays. One lamb’s lettuce seed was manually sown in each cell. The trays were kept in a dark germination chamber at 18±2°C and 85% humidity for 3 days, and then transferred to the greenhouse. Until reaching transplant size (32 days), only watering was applied as needed to the seedlings in the greenhouse. Some agromorphological and physiological measurements were measured on seedlings with 4-6 true leaves and ready for transplanting. The data obtained showed that as the proportion of biochar added to the seedling growing medium increased, the morphology and quality of the seedlings improved. The application with 20% biochar (20%BC+80%P) provided better results compared to other biochar-added applications and yielded nearly the same results as the control with peat, which is a commercial seedling production medium. In conclusion, the addition of biochar to the seedling growing medium improved the seedling growth and quality of lamb’s lettuce seedlings, and it was suggested that different mixing ratios should be explored. © 2025 Elsevier B.V., All rights reserved.