Buy Organic Shiitake Mushroom Grow Kit Fruiting Block. As long as the ambient humidity in the growth area is constant, shiitake are a dependable producer. Shiitake blocks are prone to drying out since they are completely removed from the bag once they are ready to fruit. If you have been looking for the best place to order this strain, Mandy’s psychedelics got you covered. If you have any question about this strain, just contact our customer service and you will get answers. This fast-growing strain of Shiitake is our favorite mushroom here on the farm. Once you activate your Shiitake mushroom grow kit, the first harvest will begin growing and will form big beautiful mushrooms over 10 to 14 days.  Our Shiitake blocks produce 1-2 crops. Experience the joy and wonder of watching beautiful mushrooms grow before your eyes and then eating them.