How hardy are mycorrhizae?
Shelf life of our standard products are 2 years with a 10% decrease in viability in year 3. Cold temperature, even freezing, does not affect the viability of mycorrhizal propagules that are most commonly used as inoculum. High temperatures, above 140 degrees F, damage mycorrhizal propagules and should be avoided. Once the propagules are mixed with the soil, they remain in a dormant state until there is root activity. Mycorrhizal propagules germinate in the presence of certain root exudates. Once the spores germinate and attach to the root system, the mycorrhiza will remain with the plant for the life-cycle of the plant. Plants growing on stressed sites or frequently disturbed sites may require several inoculations.
