Methods of propagating Arbuscular Mycorrhizal Fungi (AMF) are described that do not require the addition of, or presence of, any detectable live host plant material or live plant root material. The method comprises addition of water and optionally exposure to sunlight. It was surprisingly found that soil devoid of any detectable live host plant material, including host plant roots, is capable of supporting AMF reproduction, though it is widely believed that AMF are obligate symbionts requiring live plant roots for colonization to reproduce. Described methods optionally include active removal of living host plant material from the soil prior to AMF inoculation. Optionally, phosphorous compounds are added to the soil prior to inoculation. It was found that addition of phosphorous compounds, such as phosphite, to the soil enhances the growth of AMF spores by as much as three-fold over controls having no added phosphorous compounds.