Biodegradable Nursery Pot from Paper Labeling Waste Enriched with Coffee Grounds and Soybean Meal

Abstract

This research aimed to develop biodegradable nursery pots from labeling waste (LW) enriched with nutrients by incorporating coffee grounds (CG) and soybean meal (SM), molded with cassava starch glue. The results revealed that the suitable material ratios for pot formation were LW:CG at 50:50, LW:CG at 75:25, and LW:SM at 75:25. Both the quantity and type of raw materials influenced the physical properties of the pots. All formulations demonstrated structural stability with a friability index of 0.99–1.00. However, LW:SM at 75:25 exhibited the highest water absorption, leading to the lowest stability and the fastest biodegradation. Both CG and SM contributed additional nutrients to plants, while LW:SM at 75:25 provided superior nutrient enrichment compared to LW:CG, as soybean meal supplied a higher nitrogen content. When tested with chili seedlings (Capsicum frutescens L.), the LW:SM (75:25) pots supported the greatest growth performance, yielding a fresh weight of 4.45 ± 1.76 g, dry weight of 0.44 ± 0.17 g, stem length of 2.12 ± 3.26 cm, and root length of 4.42 ± 0.84 cm, which were significantly higher than other formulations (p < 0.05). Visual observations further confirmed that plants grown in LW:SM (75:25) pots had the highest leaf number and largest leaf size. These effects were attributed to the favorable physical properties of soybean meal, which enhanced porosity after biodegradation and directly promoted root development, as well as its chemical composition, containing ammonium-nitrogen and nitrate-nitrogen (2%), urea-nitrogen (15%), phosphorus (5%), and potassium (16%). In conclusion, nursery pots produced from LW:SM at 75:25 not only degraded efficiently but also enhanced nutrient availability and plant growth, offering a sustainable alternative for cultivation and environment.