Mycorrhizae Inoculants: Do They Actually Help Trees?

Mycorrhizae are beneficial fungi that partner with plant roots, exchanging nutrients for carbohydrates. While the symbiosis is vital in nature, commercial inoculants show inconsistent results.

Research highlights:

• Many products fail to establish viable colonization.
• Native mycorrhizae often already saturate the soil.
• Benefits claimed by manufacturers are rarely replicated in independent trials.
• Non-native fungal strains may not function in local conditions.
• Often, added fertilizer in the product—not the fungi—causes any observed growth boost.

Dr. Jim Downer's analysis concludes: don't rely on mycorrhizal products as a magic bullet. Proper planting, mulching, and fertilization are more reliable.