The Effect of Onion Soaking Water Concentration (Allium spp.) on the Growth of Pakcoy Mustard (Brassica rapa L.) Using a Hydroponic Planting Medium

Abstract

This study aims to analyze the effect of various concentrations of liquid organic fertilizer (POC) made from shallots (Allium spp.), garlic (Allium sativum), and onions (Allium cepa) on the growth of pak choi (Brassica rapa L.) in a hydroponic system. The parameters observed included the number of leaves and leaf area during four weeks of growth. The results showed that shallot POC with a concentration of 15% provided the most significant increase in the number of leaves, from 6 leaves in the first week to 10 leaves in the fourth week, and leaf area from 5.00 cm² to 10.20 cm². However, the results of the one-way ANOVA test on the number of leaves showed a significance value of 0.075 (p> 0.05), which means the difference is not statistically significant. On the other hand, the increasing trend indicates a potential positive effect that requires further testing.Garlic POC showed unstable growth results, especially at concentrations of 5% and 10%. Although the 15% concentration showed a slight increase in leaf area (up to 8.91 cm²), the ANOVA test showed a significance value of 0.001 (p < 0.05), indicating no significant effect on the number or area of ​​leaves. Meanwhile, onion POC at a concentration of 15% showed more consistent growth, with an increase in the number of leaves up to 8 leaves and leaf area up to 9.37 cm². The ANOVA test on leaf area showed a significance value of 0.128 (p > 0.05), indicating that although the increase occurred, it was not statistically significant.Water parameters such as pH and temperature did not show significant differences between treatments, while ppm values ​​tended to increase at higher POC concentrations, indicating an increase in nutrient content. Overall, although not all results were statistically significant, these findings indicate that onion POC, especially at a concentration of 15%, has the potential to be an effective alternative source of natural nutrients to increase the vegetative growth of pak choi plants in hydroponic systems.