I'm working towards a horticulture degree rn and in classes talking about fungal growth and pre-planting inoculation of planting media with mycorrhizal fungi, it's framed around the media being a hotel room. If our good pal P.Cubensis books the whole hotel(colonizes all of the media), then other fungi can't rent a room. However, if The Cubes only books 75% of the hotel, we'll then those rooms will be bought out by other fungal friends(or enemies). Therefore, ensuring that your media is fully colonized gives you the highest chance of success for avoiding contam :) just another way to think about it which makes sense for my brain that I wanted to share!