Bio-available Fertilizer for Hydroponic Lettuce (Lactuca sativa L. var. longifolia)from byproducts of Chlorella vulgaris

The byproducts of Chlorella vulgaris contain biochemical components, essential nutrients, and biomass, making them viable as bio-available fertilizers for hydroponically grown lettuce (Lactuca sativa L. var. Longifolia) using the Deep-Water Culture (DWC) system. This study aimed to offer an environmentally friendly alternative to chemical fertilizers, particularly for dry season farming in the Philippines, where chemical inputs contribute to environmental degradation and rising production costs. Exploring alternatives like C. vulgaris promotes sustainability, resource efficiency, and supports the UN Sustainable Development Goals. The bio-available fertilizer derived from C. vulgaris significantly improved lettuce growth and survival compared to chemical fertilizer and control groups, demonstrating its potential as a sustainable hydroponic input. A six-week experiment using two-way repeated measures ANOVA and descriptive statistics showed that the bio-available fertilizer led to significantly greater shoot length, root length, plant height, leaf area, and number of leaves than the control. It also outperformed chemical fertilizer in shoot and leaf growth. Survival rates were highest in the biofertilizer group, confirming its adaptability under dry-season stress. However, overall growth was still lower than in greenhouse-based studies, such as that of Frasetya et al. (2019), where lettuce reached a height of 22.73 cm under controlled conditions. In contrast, the highest shoot length recorded in this study was 8.6 cm under biofertilizer treatment, highlighting the influence of environmental factors like temperature and humidity. The study concludes that Chlorella vulgaris byproducts can serve as an effective and sustainable alternative to chemical fertilizers for hydroponically grown lettuce.