The IIHRPF-1 strain of oyster mushroom (Pleurotus florida Mont. Singer) is gaining popularity in India due to its distinctive flavour, high nutritional value and increasing consumer preference, often surpassing the commonly cultivated button mushroom (Agaricus bisporus). Optimisation of cultivation parameters, particularly substrate type and spawn rate, is essential for improving growth, fruiting and yield. This study evaluated the growth performance and yield of P. florida on three different substrates rice straw, powdered rice straw and sawdust using three spawn rates (40, 50 and 60 g kg-1 of dry substrate). Cultivation was carried out under controlled conditions with relative humidity maintained at 57–70 % through a sprinkler system to ensure favourable conditions for pinhead initiation and fruiting body development. Among the tested combinations, rice straw at a spawn rate of 50 g kg-1 produced the highest yield of 193.33 g kg-1 dry substrate and the highest biological efficiency of 50.09 %. This treatment also resulted in the earliest pinhead initiation, the most rapid fruiting body formation and the shortest interval between successive flushes. The findings indicate that rice straw combined with a moderate spawn rate not only optimises growth and yield but also ensures efficient and sustainable mushroom production. Furthermore, this approach promotes the utilisation of agricultural residues, providing an environmentally friendly strategy for mushroom cultivation. These results offer practical insights for small and large-scale farmers aiming to improve the productivity and profitability of P. florida cultivation.
