The mold form you use will determine the final shape of your grown mycelium. Here are some general tips about forms and the growth process before we get into ideas for making/using forms:
- As it dries out the mycelium will shrink in size by about 10% so keep that in mind when deciding the size of your mold.
- The mold material has to be something that the mycelium won't stick to, such as plastic, glass, or tape. If you use cardboard or wood you have to cover it with tape or saran wrap. The mycelium will grow into any organic material and really bind itself to it and you won't be able to get it out. I had a student make a mold out of Legos and it managed to adhere to the tiny cracks between bricks and was really hard to remove.
- The design of the mold will need to allow for removal of a potentially fragile shape, so consider how you will be able to get it out without too much pulling and squeezing. It won't just fall out.
- Parts of the mycelium that are not covered will grow thicker with white fluffy material while parts that are against the mold will have exposed substrate that the mycelium can't cover, but the latter will get covered when the mold is removed for the second growth phase. So, for example, if you want a container to have a smooth even surface on the inside, you have to add an inside form it will grow against. Without an inside surface the inside of your container will be bumpy.