Over the past several decades, a strong interest has developed in the identification and culture of beneficial soil organisms. It is documented that many bacteria and fungi can help plants in combating diseases, locate nutrients and acquire water when in short supply. Within the beneficial organisms exists a complex group of fungi called mycorrhizae (Figure 3, page 20). These fungi grow in association with most plants and have been investigated as growth and quality enhancers for agriculture and horticulture crops.

Most mineral soils contain mycorrhizal fungi, but often at levels that are too low for adequate colonization, especially in disturbed soils (tilled fields, gardens, landscapes, new housing, etc.). Mycorrhizae are host specific and will only colonize certain plants; so in some soils, there are no native mycorrhizae that will benefit these plants. Therefore, most plants would benefit from mycorrhizae addition to the soil.

Greenhouse crops are grown mostly in soilless media which consists of a base of peat moss, bark and/or coir. These organic components along with the growing medium they compose do not have mycorrhizal fungi strains that would benefit the crops grown in them, so they must be incorporated.

What are Mychorrhizae?