Inoculation is the process of introducing spores or mycelium culture to a substrate.
Inoculation of spawn substrates
Most successful cultivators are diligent to maintain sterile conditions when performing any type of inoculation that doesn't involve the mass introduction of a fully colonized spawn substrate into a bulk substrate. When spores or small portions of mycelium are introduced to a highly nutritious substrate, other microscopic contaminants are just as likely to take control of the substrate if given the chance. In order to limit the introduction of competition during inoculation, spores and liquid culture are usually injected through a filtered lid with a flame sterilized needle. It is also very common to use a glove box or laminar flow hood in order to further limit the likelihood of contamination.
Spore syringe A spore syringe is a scientific syringe filled with sterilized distilled water and mushroom spores. Syringes are a common method of inoculation by beginners and adept alike due to ease and resilience to less than sterile conditions. Pre-filled syringes are commonly available from many online vendors for cultivation use (in the case of edible species) and for microscopy use (in the case of psychedelic species).
Liquid culture syringe Liquid culture can be moved to a syringe to be used for substrate inoculation in the same way that a spore syringe is used. Liquid culture consists of a distilled mixture of water and nutrients. Commonly used nutrient sources include Karo and honey. Nutrients and water allow spores to germinate and begin mycellial growth before inoculation. Many online vendors will only sell edibles inoculate in culture syringes or slants.
Agar wedge When cloning mushroom tissue or isolating a strain, the work is usually done on agar plates. From these plates, the tissue can either be dropped into a liquid culture, or more commonly, directly into a spawn substrate jar.
Grain-to-grain transfer (G2G) In order to quickly increase the amount colonized spawn substrate, a colonized grain jar can be shaken and transferred to other, un-colonized jars. Since a small amount of kernels can effectively inoculate h a whole new jar of grain, grain-to-grain transferring can dramatically increase the amount of available spawn substrate. Online retailers may carry grain spawn or "plugs," inoculated wooden dowels used to colonize solid wood substrates.
Inoculation of bulk substrates
Bulk substrates are rarely directly inoculated with spores or tissue culture. They are almost always inoculated with a spawn substrate in a process commonly referred to as "spawning". During this process, the bulk substrate is hydrated to field capacity and pasteurized before a spawn substrate is broken up and mixed with the material.
When moving a large amount of fully colonized spawn substrate to a mildly nutritious bulk substrate, the mycelium has a great advantage over any other contaminants due to its full colonization of the highly nutritious substrate and its many points of inoculation throughout the bulk substrate. Because of this resistance to contamination, many cultivators perform bulk inoculation in open air environments that have merely been cleaned carefully beforehand.