The word mycorrhiza literally means “fungus root,” and there are several thousand different species of mycorrhizal fungi that have been around for hundreds of millions of years.
Think of mycorrhizae as underground mushrooms that appear as fibrous white strands (much thinner than human hair). In the soil, these strands naturally infect the roots of their host plant, thereby forming a mutually beneficial (symbiotic) relationship.
How it works: The fungi pull up water and nutrients that would otherwise be unavailable to your plants, and in turn, your plants provide the fungi with needed sugars and carbon that are produced through photosynthesis.
You see, some plant nutrients move verrrrry slowly in the soil. This sluggish movement shows up as a deficiency in the plant—for example, phosphorus, which is mostly insoluble. This makes it unavailable to plant roots, and that’s where mycorrhizae come in.
The fungi can convert soil nutrients into a more soluble form and deliver them to the plants’ root system, causing more branching and improving the roots’ ability to store water and nutrients.