There are a lot of companies putting out microbes. I was down visiting Agrobest at Nerang who put out an extensive range of products including fertilisers, trace minerals, soil conditioners, crop protection & nutrition etc. and I asked them what conditions were needed for microbes to work successfully. There are 3 components: moisture, temperature and composted soil. The warmer the soil temperature, the faster the microbial population will expand with growth being very slow under 12ºC. Ideally apply in spring or later. To achieve optimum growth, a readily available food source for the microbes is required. This may be plant material in the form of humus on the top of the ground or incorporated and organic carbon in the soil. It is suggested that if the soil has very low organic carbon levels below 0.9% and lack of humus, that a good food source is added when applied. Molasses or fish emulsion is suitable for this. Another point that is relevant is that some microbes will eat other microbes!
Richard Poli our last guest speaker says that some microbes require dry conditions to populate; some require warmer temps and some like it cool, some like it dry and cool but must have morning dews to enable increases.
Row crops need bacterial microbes but tree crops need fungal microbes in the form of kelp, fish, and humates.