Sterilized and prepared mushroom grain spawn substrate (1 lb.) in a gusseted autoclave bag with filter patch and self-healing injection port. Shroom Supply grain spawn is composed of 100% USDA certified organic rye berries which is widely regarded as the highest quality grain for spawn production and is the industry standard for mushroom cultivation. The substrate is free of any additives or chemicals and is recommended for use with pre-pasteurized mushroom compost.
Once colonized with mushroom mycelium, we recommend using the colonized grain spawn to inoculate a bulk substrate, like premium pre-pasteurized mushroom compost. We recommend spawning two pounds of our grain spawn to five pounds of our compost. Alternatively, the colonized grain spawn can be transferred to more sterilized grains to promote further propagation of the mushroom mycelium (also known as a grain to grain transfer).
We prepare our organic rye berry grain spawn by thoroughly rinsing the grains, then soaking them for 18 hours in a gypsum-fortified water bath to ensure optimal moisture and mineral levels. Immediately after the soak, the rye is simmered for 10 minutes in distilled water. The rye berries are then sterilized at 15 PSI in a lab-grade autoclave for a complete 120 minutes.
Our grain spawn comes heat-sealed in a sterile, filter-patch mycobag with injection port and can be stored at room temperature for up to 14 days before use. If longer than 14 days is needed, the grain can be stored in a clean container in the refrigerator for up to six weeks. Do not freeze.
All sterilized grain spawn will come packaged in individual 1 lb. bags, regardless of quantity ordered.