The organic waste treatment process using Black Soldier Larvae (BSF) produces liquid biofertilizer (LB) that contains functional microbes and macro and micronutrients that potentially can stimulate plant growth. The study aimed to determine the effectiveness of liquid biofertilizer from waste bioconversion by BSF on the growth of arabica coffee seedlings. The experiment used a randomized block design with 7 treatments, which consisted of: no treatment (control), 1.5% LB spraying, 3% LB spraying, 6% LB spraying, 3% LB watering, 6% LB watering, and 12% LB watering, with 4 replications and each replication containing 10 plants. All treatments were given once a month, to the 1-month-old seedlings. The test results showed that the application of LB significantly increased stem diameter and the number of leaves of Arabica coffee seedlings 4 months after application (MAA). In seedlings aged 4 MAA, spraying 6% LB resulted in the highest increase in stem diameter, while the highest number of leaves was obtained from watering 3% LB. Additionally, in 12 months old seedlings, Arabica coffee's highest fresh shoot weight was obtained by spraying 1.5% LB compared to other treatments.