Ash content ranged from 5.90% to 7.10% of mushroomPO and 6.30% to 7.57% of mushroom PC. In comparison tocontrol substrate formula, only substrate formula 100% CCgave a significant difference in ash content of mushroomPO. Other substrates gave the same result in ash content,whereas the highest value of ash content of mushroom PCwas observed from substrate containing 100% CC, 50% CC,100% SB, and 50% SB and it was significantly higher thanthat of mushroom PC grown on control substrate formula.The ash content in this experiment was in accordance withthe value reported by Bonatti-Chaves et al. [49] when POand P. sajor-caju were grown on different lignocellulosicwastes.