Fungi grow where mild falls and very little penetration resistance prevails. Since mild also falls on the perimeters on the cake, fungi can grow there in addition. This is hard to avoid. We usually discourage darkening the edges of your grow box, as it's additional destructive consequences than favourable types. https://golden-teacher-mushroom-g99764.dailyblogzz.com/26978692/the-best-side-of-golden-teacher-mushroom-growing