This video outlines the fourth step in the process of mushroom cultivation, making a "fruiting tray". This step combines colonized grain with Vermiculite and Coconut Coir (pressure sterilized) to form a substrate with enough nutrients for mushrooms to grow. The tray is then placed in a dark environment for 7-10 days to allow the mycelium to colonize the entire substrate, then moved into a lit area to trigger the fruiting period of the mushroom life cycle.
We use locally sourced Vermiculite and Coco Coir (50/50mix). All of this tray-building work is done after extensive cleaning, and in front of a flow hood continually blowing filtered air. It is highly recommended that any mycological work is done in front of a flow hood to reduce the chances of contamination later in the mycological life cycle.
Once you have completed the steps shown in this video your fruiting medium will be ready in 7-10 days (when the top becomes white with mycelial growth). At this point it can be removed from the darkroom and placed on a 12/12 light cycle. Approximately one week after the tray is removed from the darkroom it will begin to "pin" or sprout tiny mushrooms.