Growing mushrooms requires both the right spores or spawn, as well as an ideal substrate, in order to ensure success. Mushroom substrate is essential because it serves as the canvas on which mycelium grows – this ultimately becomes your crop! There are countless substrate options for mushroom growers from logs and stumps to coffee grounds and tea leaves; alternatively there are kits which offer all necessary supplies at an economical price. With some creative thinking you could use any item as an effective mushroom substrate!

Hardwood sawdust is one of the most widely-used substrates for mushroom growing, found at home and garden stores. This material offers many advantages – being both inexpensive, easily available, and rich in nutrients. Often pasteurised or sterilized prior to being used as mushroom substrate (removing any harmful microorganisms), although this may not always be necessary if using low nutrient substrates such as straw which contain few contaminants in its original state.

Manure is another popular mushroom substrate, though its preparation can take more effort. Mixing manure with straw and composting it (heating it to 72degC for several hours to kill off “bad” microorganisms while simultaneously benefitting healthy ones) are all effective approaches; however, for most growers this process may not be practical and it would be prudent to purchase pre-packaged bags of pasteurised and sterilized manure and straw instead.

Vermiculite is another excellent substrate choice that’s easily available both online and through gardening centers. Packed full of humus-rich soil particles and excellent moisture retention properties, vermiculite should be pasteurised or sterilized before mixing it with other materials; or you could mix vermiculite with hardwood sawdust to boost colonisation ability and nutritional content.

Researchers recently conducted an experiment utilizing different ratios of waste tea leaves (WTL) and rice straw (RS) in oyster mushroom substrate formulations for Pleurotus ostreatus mushrooms, concluding that adding WTL significantly enhanced yield and biological efficiency of both strains of mushrooms.

Cotton fiber, an organic and biodegradable option, as well as coconut fiber (coco coir), provide ideal moisture levels and prevent the substrate from compacting too quickly for easier cultivation. Coco coir can also be recycled by using agricultural byproducts in its production. Spent shiitake blocks may also be added as they contain pathogens that inhibit growth – for this reason it should first be subjected to either hot water pasteurisation or hydrated lime soak treatment before being introduced into a substrate.