Mushrooms are not plants but are fungi. Yep they are related to that green mold that grows on your bread when it gets old or the mildew that may grow around your tub. They do not reproduce by seeds but instead produce spores that are released from the mushroom when it's mature. Most mushrooms do not require light to grow like plants do, since they do not have chlorophyll to carryout photosynthesis. So you want to learn how to grow mushrooms? Well let's start with some basic terminology.
Spores-Mushroom spores are produced on the gill of the cap of the mushroom. There are microscopic and similar to seeds of higher plant life. Spores are used to spawn mushroom compost.
Spawn-Rye, wheat, millet etc. are cook with water and sometime gypsum is added then it is all steam sterilized. Mycelium is added to whatever grain you used and are allowed to grow for 10-17 days. The mycelium will completely colonize (grow) on the grain and this is called spawn.
Mycelium-The vegetative part of a fungus, consist of many fine white filaments called Hyphae.
Hyphae-Single strands of mushroom mycelium.
Primordia (pins or pinheads)-tiny fruiting mushrooms that are roughly 1/8 to 1/4 of inch in diameter.
Inoculation-The process of introducing spores or mycelium culture to a substrate.
Substrate-its the material the mushrooms live on and grow. Depending on the mushroom the substrate maybe different. Some examples are compost, wood, sawdust, hay etc.
Incubation-The time after inoculation and before the mycelium has fully colonized its substrate. This step is done in a sterile environment to prevent/reduce contamination.
Casing Layer-The top dressing that is required to induce fruiting and cease mycelium production.
Basic Mushroom Anatomy
Gills- spores are released from the gills of mature mushrooms
Stipe or stem-supports the cap of the mushroom
Mycelium (hyphae)-similar to roots. This is where a fungus absorbs its nutrients.
Basic Mushroom Reproduction
Mushrooms reproduce by releasing spores. If these spores fall on the correct substrate for them to grow they germinate (begin to grow). They start by developing mycelium. The mycelium keep branching out until there a trigger to tell them that they need to start forming fruit bodies. This trigger can be a number of things like: changes in CO2 levels, reaching the surface of the substrate they are in, coming into contact with the casing layer (which I will discuss later) or a decrease in nutrients. At this point the mycelium begin to produce pinheads (small immature mushrooms). The pinheads grow and if not harvest will reach maturity and start the process all over again.