Inoculating Stumps with Sawdust Spawn Posted on June 14, 2017 by MycognosticSeptember 11, 2017 Cardboard on the forest floor. Covered with Blue Oyster Spawn. A stump is placed on top. Sawdust/woodchip spawn is crumbled around the sapwood. The second piece of the stump is stacked upon the first, sandwiching the spawn Keep on stacking and sandwiching layers of spawn. In a few days the mycelium has jumped of the spawn and started to colonize the wood. Three weeks later with regular rain and watering, a little flush of one mushroom was a good sign that the spawn is happy.