Bulk substrates cannot be inoculated using liquid culture or spore solution, and so one of the first steps in a bulk grow is creating grain spawn in order to inoculate the bulk substrate.

Can you inoculate substrate?

As soon as the substrate is fully colonised by the mushroom, you can set up the bag for fruiting. To avoid invasion of any contamination during inoculation, we recommend to disinfect the surface (the place you want to put the needle in). ... Inoculation: Shake the syringe to dispense the spores equally.

How long does it take for bulk substrate to colonize?

It will take approximately 5-10 days for the substrate to completely colonize with mycelium (you will be able to tell if it has completed colonization when the substrate has turned completely white).