Brown Rice Flour&vermiculite Mushroom Substrate 6 Jars (1/4 Pint Jar) Growing Kit Mushroom Substrate Jars. Brown Rice Flour & Vermiculite Mushroom Substrate Jars 1/4 Pint Jar *6 Jars. PH Balanced BROWN RICE Flour and Vermiculite mushroom substrate (small size for fast colonization) We use best quality porduct to get best result: Horticultural grade vermiculite Organic Brown Rice Flour Hand Milled Organic Rye Grain Flour Non-Chlorinated water The substrate are already Pressure Sterilized and ready for inoculation on arrival. Jars are MADE AS ORDERED to ensure freshness and are good up to 2 month refrigerated. Each Jar has a tyvek filter disc under the pre-drilled lid ( 4 point holes for inoculation) and covered by foil top and wrapped by shrink plastic wrap and foil wrap for protection. Jars are wrapped again with plastic wrap Directly form the pressure cooker to guarantee sterility. 100% contamination free Guarantee . 100% sterile and ready to inoculate!