Maximum Yield USA November 2018 | Page 50

Even inert substrates such as stonewool are colonized by rhizosphere microbes. Studies have shown that inoculating hydroponic systems and different plant species with these bacteria led to increased root growth and enhanced formation of lateral roots and root hairs, which may be at least partially attributed to bacterial IAA. This results in an enhanced tolerance to plant stress and improved ability to take up water and nutrients. While a large number of proven beneficial bacteria exist, fungi also contain some highly effective species that have been proven in both soil and hydroponic systems. One of the most significant of these is Trichoderma. Others are arbuscular mycorrhizal fungi such as Gliocladium virens, non pathogenic F. oxysporum, Paecilomyces lilacinus, Penicillium chrysogenum, and a number of others identified in studies as having an antagonistic effect on pathogenic fungi. In many of these studies it has been discovered that combinations of synergistic fungi species often have a greater effect on disease control than when used singly. 50 Maximum Yield Coconut fiber substrates are easily inoculated with beneficial fungi and bacteria inoculant sources. INOCULATION OF MICROBES While naturally occurring, beneficial microbes do typically self-inoculate into new hydroponic systems, however, this can be a slow process and species diversity may be limited. Well-established hydroponic systems, where microbial life is not being continually killed with the use of sterilant, biocide chemicals such as chlorine or hydrogen peroxide, ultraviolet or ozone treatment, or other methods, tend to have a greater diversity of beneficial microbial species than newer systems. Microbes can be introduced through several different methods. Commercial, packaged inoculant products designed for hydroponics are now widely available and since these contain species known to be beneficial, they are a good place to start. Ideally, since different microbial species carry out different roles and have varying effects on growth, disease control, and other factors, using a product that has a diverse mix of species as a general first inoculant is a good idea. Such inoculate products are often designed to be added directly to the nutrient solution, however, some are in more widespread use as substrate inoculant products incorporated into the growing medium before planting. If using inoculants such as Trichoderma, it’s often easier to establish beneficial microbes into a new substrate as little competition exists from microorganisms already present. But if the substrate is rela- tively inert, such as stonewool or other synthetic growing mediums, this is initially a difficult environ- ment for microbial life to take hold.