How much does it cost and how much space to start button mushroom farming?

Button mushroom is the most grown mushroom in India but it is also the most demanding because it needs cool temperature and proper compost. To start small you can begin in a single room of about 200 to 400 square feet with shelves or racks in layers, which lets you keep around 100 to 200 compost bags or trays. A small seasonal setup in a room you already own can often be started in the rough range of 50,000 to 1,50,000 rupees if you buy ready compost and just run one crop, but a controlled environment room with cooling and racks runs much higher. Button mushroom fruits best at about 14 to 18 degrees C, so in most of the plains you can only grow it in the winter months without a cooling system. The single biggest mistake beginners make is underestimating temperature control. Please treat these figures as a rough range and get exact costs and a local crop calendar from your nearest KVK or the ICAR Directorate of Mushroom Research (DMR) at Solan before you invest.