Using Mycorrhiza in Cultivation

In short: Mycorrhiza is a symbiosis in which a fungus supplies water and nutrients and the plant returns sugars. It occurs in roughly 95% of plants, with arbuscular mycorrhiza in 90%. Apply mycorrhizal products directly to roots at planting, then avoid fungicides for at least several weeks.

Mycorrhiza means a symbiotic relationship between a plant and a fungus. The fungus supplies water and nutrients, while the plant provides the fungus with sugary substances and hormones. It is therefore a mutually beneficial coexistence.

This relationship is completely normal in nature, mycorrhiza occurs in the vast majority (approximately 95%) of all plants. Nowadays, however, mycelia are often destroyed by the use of chemical preparations, mineral fertilizers, plowing and soil compaction.

Fungi are very sensitive to these factors and cannot survive intensive cultivation. Without them, however, it is much more difficult to grow anything - plants suffer more from drought and nutrient deficiency, which would otherwise be supplied by the beneficial fungus.

The Principle of Mycorrhiza

When the mycelium encounters the roots of the right plant species, an "infection" actually occurs - the fungus forcibly penetrates into the intercellular spaces or directly into the cells of the outer part of the root. Subsequently, a balanced relationship is established from which both sides benefit.

The mycelium is a dense network of fine filaments that multiply the surface area of the root several times and thus enable more efficient transport of water and dissolved substances.

In turn, fungi obtain products of photosynthesis from the plant, which they themselves are unable to produce because they lack chlorophyll. They can also receive growth-promoting substances. In some cases, the symbiosis may turn into parasitism if one of the organisms gains too much dominance.

Types of Mycorrhiza

According to how the symbiosis arises, we can distinguish several different categories:

Endomycorrhiza

This is the more common form of symbiosis. In this type of mycorrhiza, fungal filaments penetrate inside the root cells. The fungi that participate in this relationship are mostly unable to survive independently.

Types of endomycorrhiza include:

• Orchidoid mycorrhiza - many orchids are completely dependent on the fungus during germination because the seeds contain virtually no nutrients

• Arbuscular mycorrhiza - the most common type of mycorrhiza overall, occurring in 90% of plants. The hyphae branch inside the cells.

• Ericoid mycorrhiza - typical for acid-loving plants (blueberries, azaleas, heathers...)

Ectomycorrhiza

A less common type of mycorrhiza. The fungus forms a mantle on the root surface and replaces the root hairs. The hyphae do not penetrate inside the root cells, only into the intercellular spaces.

Plants with this type of mycorrhiza tend to have reduced roots with missing root hairs, often dichotomously branched. They include some conifers and forest deciduous trees - birch, oak, beech, spruce, larch, pine.

The fungi that form this symbiosis are well known to every mushroom forager - these are often species that produce large, sometimes even edible fruiting bodies (ascomycetes and basidiomycetes). Most edible mushroom species form ectomycorrhiza.

How to Obtain and Maintain Symbiotic Fungi

Mycorrhizal fungi occur abundantly in nature. However, in cultivated areas or in purchased substrate in pots, they usually don't get a chance.

One way to obtain these fungi is to transfer some soil from a plant in nature to one in your garden. However, the success rate is not very high, and you may also bring some harmful organisms along with the beneficial fungi.

A similar approach is placing sawdust near a plant where we expect mycorrhiza - the mycelium should grow into the sawdust and we can then transfer it to the garden. However, the pitfalls are the same as in the previous method.

It's always important to find the same tree or plant, because mycorrhizal fungi are often very highly specialized - one species of fungus may be able to establish symbiosis with perhaps only one plant species.

Much simpler and more reliable is purchasing mycorrhizal products. These contain the correct fungal species according to what the product is intended for, and moreover in sufficient quantity.

They can be applied by watering or in gel form or as a solution during planting directly onto plant roots. Application during planting is most effective.

Furthermore, once you use the product and the mycelium establishes properly, the fungi will remain in the soil if you grow the same crop every year and don't use many fungicides.

It's important to remember that mycorrhiza is also a fungus, even though it's beneficial. Therefore, after applying the products, don't use fungicides on the plant for at least several weeks, preferably avoid them completely.

If you want to enable rapid mycorrhizal development, it's better to avoid applications of artificial fertilizers and use organic and organomineral fertilizers instead.

Mycorrhiza is not suitable for all environments. If your garden is waterlogged or very rich in all nutrients, applying mycorrhiza won't have much significance.

Fungi need soil oxygen, just like plant roots, so they won't survive long in waterlogged soil.

When plants have sufficient water and nutrient supply, the fungus has little significance for the plant; on the contrary, it may take away some substances that the plant could use for its own growth.

However, few soils are so rich that the fungus doesn't benefit the plant - microelements are particularly important, which often lie at greater depths or are bound in minerals, from where the fungus can obtain them.

Mycorrhiza is particularly beneficial in conditions with lower micronutrient levels (you can usually observe leaf paling and yellowing on plants, or spots and marginal leaf necrosis), in drying soil or in places where there is a risk of disease attack.

Mycorrhiza enables the supply of even less available elements and water to the plant, thereby reducing plant stress associated with moisture deficiency. Thanks to this nutrition, water supply and certain substances, the plant with symbiotic fungus is more vital and resistant to stress and diseases.

Mycorrhizal products help plants grow quickly and yield abundantly. Try them yourself, you'll notice the difference!

Written by Eliška Kadlecová