Stephanie Garcia
Photo courtesy of Mycorrhizal Applications
Amy Schroeder
Photo courtesy of Mycorrhizal Applications

Many growers are looking for a way to strengthen plants’ roots and improve plant growth. Below, associate research scientist Stephanie Garcia and sales account manager Amy Schroeder from Mycorrhizal Applications explain how mycorrhizal fungi can help growers.

Greenhouse Management: What should growers know about adding mycorrhizae to their growing practices?

Stephanie Garcia: Mycorrhizal fungi connect with plant roots to form a mutually beneficial symbiotic relationship. Because this association occurs within and around the plant roots, applying mycorrhizal products as close to the growing roots as possible will achieve maximum efficiency of the inoculum. Adding mycorrhizae to a growing protocol takes relatively little effort in exchange for the long-term results that are achieved. These fungi are small but powerful tools to achieve optimum growth in 95 percent of plant species on the planet. (A list of Mycorrhizal Plant Species and Genera is available at

Amy Schroeder: There are a variety of mycorrhizal application methods that can easily be integrated into a professional grower’s current practices. The mycorrhizae can be applied as a soil drench, plug or plug tray dip, incorporated in growing media, or applied via various irrigation methods. We recommend applying the mycorrhizae as soon as possible in the growing process to maximize the impact and cost efficiency.

GM: What production issues can the utilization of mycorrhizae help growers solve?

AS: Mycorrhizae can increase drought tolerance, shelf life, and transplant success. These impacts can ensure the success of the plants when they are purchased by the customer, resulting in happy, returning customers. These impacts can also ensure the plants hold up well during shipping and retail conditions. This results in visually appealing plants that are quickly purchased by customers.

SG: Mycorrhizae are extremely beneficial to growers who experience drought stress and/or saline conditions. These fungi help reduce wilting by maintaining water uptake and maximizing water efficiency throughout the growing cycle. This is helpful during water shortages or gaps in maintenance. Saline soils and/or saline water are harmful to plants, and these beneficial fungi also help balance ion uptake to protect the plants from excess salts. A balance in ion uptake directly influences the plants’ ability to uptake other nutrients, as well.

GM: How can mycorrhizae impact a grower’s use of fertilizer?

AS: Mycorrhizae increase root surface area, which allows the roots to more efficiently capture and utilize more of the fertilizer growers apply. This ensures that the grower is getting the full value from their fertilizer and reducing their environmental impact due to nutrient run-off. This increased fertilizer utilization efficiency also gives a grower the ability to reduce their fertilizer rate, which can balance out the costs of the addition of mycorrhizal inoculants.

SG: Not only can mycorrhizae allow reduction in fertilizer application rates by efficient uptake, they can also help mitigate the uptake of toxic minerals. If there happens to be heavy metals or other toxins in the growing environment, these fungi will quarantine these minerals that can cause nutrient lockout (which renders fertilizers ineffective) and harm the plant. Whether these toxic minerals are present during the production process, or later on, when the plants have been transplanted in a landscape or home garden, this benefit of mycorrhizae will lead to long-term sustainability and hardiness of the plants. — Interviewed by Chris Manning