Mycorrhizae can be applied in different ways that work best for your day to day operations. However, one basic principle should always be respected to ensure the best results: close proximity or physical contact to the plant roots or seeds. The reason is that when the mycorrhizae spores or propagules germinate, they need to be in close vicinity to the roots to establish contact so they can form the beneficial connection to further create the mycorrhizal network. For example, drench application in the field is not recommended as spores will be spread to the surface and not close enough to the seeds to establish early contact.
Follow the instructions on the package for the application that best suits your needs.