This means the humidity on the sides or bottom is better than on top of the substrate.
How to improve it:
- Mist the inside of the bag (not the cake directly) to increase surface humidity.
- Make sure the bag isn't pressed flat against the cake, leave some air space.
To harvest side mushrooms: take the cake out of the plastic container carefully after your main harvest. Pick off the side mushrooms gently, making sure nothing is left behind. Work clean.