Purpose <p>This study investigated the effect of biochar amended-discarded pig bedding upcycled into compost pellets, and use of bio-fermented liquid for chitosan coating of these pellets on nutrient release behavior, soil microbial communities, and plant growth. Methods: Dried pig bedding (P_i) of 3–5&#xa0;mm was mixed with coconut biochar (B) at 0–25% (w/w), pelletized using corn flour as a binder and labelled P_{i, p}, P_iB1, P_iB5, P_iB10, P_iB15, P_iB20 and P_iB25. All pellets were analyzed for organic carbon, organic matter and seed gemination index. Nutrient release of nitrogen (N), phosphorus (P), and potassium (K) was evaluated by shaking 1&#xa0;g of pellets in 100 mL deionized water and fitted to the Korsmeyer–Peppas model. Selected pellets (P_{i, p} and P_iB20) were coated with chitosan mixed with bio-fermented liquid (P_{i, p}-CB_{F, coat} and P_iB20-CB_{F, coat}), then applied on topsoil at the dosage of 3 and 5% for cultivation of Pakchoy (<i>Brassica rapa chinensis</i>) in a laboratory-scale greenhouse. Results: Biochar amendment can promote the N, P, K contents and improve nutrient retention with P_iB20 exhibited maximum nutrient content (0.95–1.13% N, 0.50–0.97% P and 0.95–1.28% K). Chitosan coated pellets could reduce the rate of nutrient release. The release mechanism of N and P was an erosion-controlled process, whereas K was by diffusion. Application of 5% P_{i, p}-CB_{F, coat} on topsoil enhanced the biomass yield which was related to beneficial changes in soil microbial community. Conclusion: Overall, biochar amendment and chitosan coating improved compost pellet nutrient efficiency and promoted sustained nutrient release and plant growth.</p>