Many people don't realize that you can store fully colonized spawn bags and grain jars for 2-3 months after they are colonized. If you need to wait or delay a bulk growing project, keep reading! This doesn't work with the standard half pint BRF jars, but works with any whole grain substrate — see half-pint jars vs grain jars for why the two behave differently.
Place the fully white (colonized) spawn bags or grain jars in a cool dark spot. Ideally 50-65 degrees. The mycelium will enter a dormancy phase and will not die. We recommend a cool basement or root cellar. When you are ready to start your bulk growing project, warm them up to room temp and use! We have seen spawn bags sit up to 4 months and still produce full harvests when broken up and mixed with casing.
Always start your project and add your spores as soon as possible and you can always delay the fruiting if needed! Not sure how long your bags will take to get there? Our guide to spawn bag colonization times covers what to expect. When you're ready to go to bulk, pair your spawn with a bulk substrate and follow our step-by-step monotub guide.