Growing mushrooms on sawdust | Mushroom cultivation | Biobritte mushroom farming Growing mushrooms on sawdust. Choosing a substrate for growing mushrooms is one of the most crucial aspects of mushroom growing.  Wood is considered nitrogen-poor, so grain rich in nitrogen is combined with the sawdust to provide food for newly forming mushrooms.  What is sawdust? Sawdust:   sawdust can be used as a basal substrate with success, not all sawdust can be used to grow mushrooms, softwoods can be used but its best to use sawdust from hardwoods, it's important to talk to whoever will be gathering the sawdust for you at the factory or sawmill to collect the right sawdust.  One of the most important things to note is that sawdust alone can not give rise to commercially viable crops, it is recommended that some nutritional supplements be added, supplements as wheat bran, cotton cake, soya cake, and many other supplements.                                                     How to use sawdust