<![CDATA[Background: Red onions are an important agricultural commodity, particularly as a key ingredient in traditional Indonesian cuisine. However, their cultivation faces several challenges that affect plant growth and yield, such as declining soil quality and disease outbreaks. Objectives: This study aims to test the effectiveness of using liquid organic fertilizer (LOF) made from gamal leaves (Gliricidia sepium) in enhancing the growth and yield of red onions, as well as to evaluate its potential as an alternative to chemical fertilizers. Methods: This study employed a completely randomized design (CRD) with varying concentrations of gamal leaf OF-100 mL/L, 200 mL/L, and 300 mL/L-and a positive control using NPK fertilizer. The research stages included the production of gamal leaf POC through a fermentation process, analysis of the NPK nutrient content in the gamal leaf POC, application of the POC and the positive control to red onion plants during the vegetative and generative phases, and finally, data collection through observations of vegetative growth parameters and generative yields of red onion plants according to the treatments. The data obtained were analyzed using one-way ANOVA at a significance level of α = 5% with the aid of IBM SPSS software, Version 22, and Duncan’s multiple range test to determine the best treatment. Results and Discussion: The results of the study showed that gamal leaf POC contained nitrogen (0.84%), phosphorus (0.68%), and potassium (1.6%). During the vegetative phase, the application of gamal leaf POC at a concentration of 300 mL/L yielded the best results in terms of plant height, number of leaves, stem diameter, and number of suckers. During the generative phase, a concentration of 100 mL/L showed a significant increase in the number of bulbs; however, no significant differences were found in the fresh and dry weights of the bulbs. Conclusion: Gamal leaf POC at a concentration of 300 mL/L is most effective at enhancing the vegetative growth of red onions, whereas a concentration of 100 mL/L is more optimal during the generative phase-particularly for bulb count-so the application rate should be adjusted according to cultivation objectives. These findings indicate that gamal leaf POC has the potential to serve as an environmentally friendly, economical fertilizer that supports sustainable shallot farming.]]>
