I remember my MS Thesis, experimenting with Aspergillus niger for the extraction of Pectinase. One aspect that I learn was that unlike bacteria, most fungus prefers acidic pH. Furthermore, if you observe your soil with having a bit more moisture, humidity and nutrients... ...You can observe some mushrooms growing. Typically, soil is of slightly acidic pH. However, some fungus would prefer extreme pH for their survival... ...But depends what you want to achieve from them. Is it specific enzymes, metabolites, or maybe, its biomass? pH is among other important factors to consider. .... ... .. .