What is the best way to store grain spawn? A What is the best way to store grain spawn? Category: General Growing Grain spawn should be kept in a cool, dark place, ideally in the refrigerator, and used within 3-4 weeks for the best results. If you need to store it longer, consider freezing it in an airtight container. Post navigationPrevious post: How can I tell if my liquid culture is healthy?Next post: Can I grow mushrooms from store-bought mushrooms? Leave a Reply Cancel replyYour email address will not be published. Required fields are marked *Comment * Name * Email * Website Save my name, email, and website in this browser for the next time I comment. Δ