A grow bag is a plastic bag filled with a substrate mixture of organic materials that provide nutrients for mushroom mycelium to develop. The bags are sterilized, then inoculated with mushroom spores or mycelium and placed inside a fruiting chamber to mature into mushrooms that can be harvested.

There are a few different types of grow bags available on the market. Most are made of plastic and have a filter patch for air exchange. Some are gusseted and some have a self-healing injection port. These bags are commonly used for making spawn blocks or sawdust fruiting blocks and for growing mushrooms inside of a fruiting chamber.

The best grow bags are autoclavable, meaning they can be subjected to high temperatures like those found in an industrial sterilizer. The sterilizer operates at pressure levels up to 15PSI, subjecting the contents of the bag to a temperature of 250 degrees Fahrenheit for hours at a time. Bags that are not designed for this will melt, destroying the contents of the bag.

Another great feature of these bags is the 5 micron filter patch. This prevents contaminants from passing through to the substrate during the cool down phase after sterilization. The filtration system also allows the bags to be sanitized and handled without contaminating the spawn inside of them.

A good trick to know when using these bags is to slip a tyvek filter in between the gussets, just above the substrate. This prevents contamination during the post-sterilization cool down by ensuring that any room air that enters the bag is first filtered. Psilocybin grow bags