This study was conducted to evaluate the growth and flowering of Begonia boliviensis A. DC. 'Bonfire' when grown in the growing medium mixed with pellets from biobased plastic resins containing chicken feather fibers, and analyze macro-and micro-elements in soil and leaf tissues during different developmental stages of begonia. Growth, flowering, and foliar analysis of plants grown in 10 cm pots containing 95 grams medium mixed with 6 grams each of pellet 29 (P 29), 32 (P 32), 37 (P 37), or 40 (P 40), 3 grams of Na (P NaS), or 9 grams of 45 (P 45) were similar to the control plants. Extra nitrogen was available from P 32 and P 37 based on the growing medium and foliar analysis of plants grown in P 32 (P 32 plant) and P 37 plant during the first 59 days after planting (DAP). Slow growth, low flowering percentage, or even the death of B. boliviensis 'Bonefire' grown in P NaS medium is attributed to high pH and high sulfur concentration. Based on the pH, soluble salts level, and the concentrations of macro-and micro-elements in the medium and leaves, P 45 pellet is the suitable source, if nitrogen is supplied constantly to the optimum level. Pellets prepared following mixing > 30 feather fibers without using glycerol should be further tested.Additional key words: availability of nitrogen, chicken feather pots, foliar analysis, growing medium Hort. Environ. Biotechnol. 53(1):81-91. 2012.