Since mushrooms do not contain chlorophyll or photosynthesize, their tolerance for low light in extremely high. Light itself seems only to play a part in fungi life as a photosensitive cue for fruiting. Mushrooms are made of chitin instead of cellulose, the building block of most herbaceous plants. Chitin forms long, thread-like filaments that branch off in all directions called hyphae. They look very much like the branches of a tree or a system of roots. A collection of hyphae is called a mycelium. A mycelium could be said to be the true body of a fungus.A mushroom that we see above ground is actually the sex organ, or fruiting body, of the mycelium. It carries the spores necessary for reproduction in its gills on the underside of its mushroom cap. Making mushrooms requires two hyphae to fuse together, which for the at-home grower means the inoculation of hundreds of mycelium into a growing medium.
Just like in regular hydroponics, mushroom spores need a growing substrate. Once this growing medium is inoculated with spores, mycelium will soon develop, fuse, and colonize the substrate. In order for this to happen, the growing medium must contain nutrients in some form. Once again, this is because mushrooms, unlike plants, do not make their own food. Nutrients given to fungi are consumed as their only form of energy, much in the same way that animal life is sustained. This means that mushrooms must be energized with some form of sugar or carbohydrate in order to thrive. A mushroom hydroponics system generally consists of a small tank filled with expanded clay aggregate pebbles, a water heater, humidity gauge, light, and air pump with an air stone attachment.