Elaine Levine

You can't see it. It's hard to pronounce, but mycorrhizal fungi are important to home gardeners because they affect most of the plants we grow.

In short, mycorrhizae provide plants with nutrients, particularly nitrogen and phosphorus, and plants in turn give mycorrhizae the sugars produced through photosynthesis. "Basically, 90 percent of the world's vascular plants belong to families that have symbiotic associations with mycorrhizal fungi," says Michael Miller, senior soil scientist at the U.S. Department of Energy's Argonne National Laboratory, Argonne, Illinois.

Inoculations of commercially produced mycorrhizal fungi for food crops are on the rise, but there is controversy about its use by the home gardener. So far, say the researchers in the field, if you already have healthy soil, you probably don't need inoculants.

Besides farmers, the most likely beneficiaries of inoculants are people who live in new developments where the topsoil was removed.

To encourage your own mycorrhizae:

• Avoid soil disturbance such as annual tilling.Avoid use of synthetic pesticides, especially fungicides.
  
• Avoid soil compaction.
  
• Avoid use of leaf blowers which remove organic material.
  
• Mulch with partially composted leaves and other organic material.
  
• Encourage birds and other beneficial wildlife to visit your garden.
  
• When planting native trees and shrubs, add a handful of organic duff from woodland near your home to the planting hole. This likely contains spores of locally occurring mycorrhizae.

If you decide to use mycorrhizal inoculants, look for a company that produces the inoculant in your geographic region. The nearest company to us is Bio/Organics in Santa Maria, CA.