BRF Jars Brown Rice Flour Mushroom Substrate (12 Pack)Enjoy 12 X half pint jars of nutrient fortified brown rice flour and vermiculite mushroom substrate. This is the same mushroom substrate recipe that Out Grow has used the last 10 years! Each half pint jar of mushroom substrate is fully sterilized, hydrated and ready for inoculation rite out of the box! Out Grows brown rice flour and vermiculite mushroom substrate fully sterilized in easy to inoculate half pint jars. BRF jars are the perfect growing