Mushrooms Popping up Everywhere
The topsoil in the greenhouse was removed 25 years ago in preparation for the hydroponic system. Then the sub-soil floor was covered with 6 mil 'panda' poly film which is black on one side and white on the other. The black side cuts out light so weeds don't grow and the white side up reflects light and keeps the environment cooler.
When I started reclaiming the soil for planting fruit trees in the greenhouse I purchased sterile and well composted amendments in an effort to restrict the introduction of weed seed and unwanted insects. I added Myke mycorrhizae in each hole dug for the trees and now, with the help of airborne spores I've got mycelium and mycorrhizae throughout the greenhouse.
Teresa, an amateur mycologist, visited the greenhouse in August and identified the genus Lepiota, a saprophytic fungus. This is good news because they actively feed on dead plant and animal material turning it into humus, minerals and nutrients. Another good reason to leave the fallen leaves on the ground!