Microorganisms in the soil – what do they do and why are they important?

If someone tells you that the soil is alive, they are not speaking in poetic hyperbole. A single handful of healthy garden soil contains more microorganisms than there are people living on Earth. These tiny creatures – bacteria, fungi, actinomycetes – perform the work without which no plant could thrive.

What do microorganisms do?

Soil microorganisms perform three fundamental tasks. Firstly, they decompose: fallen leaves, dead roots, and organic residues are transformed into tiny molecules. Secondly, they transform: nitrogen, phosphorus, and other elements are converted into forms that plant roots can absorb. Thirdly, they create connections: mycorrhizal fungi, for example, physically connect roots to nutrient sources, even at distances of several meters.

This triple function – decomposition, transformation, and connection – is what makes soil a living system. Without them, the soil would merely be mineral dust, with nutrients locked away in inaccessible forms.

Why are they important in your garden?

When you add nutrient solution or fertilizer to the soil, it does not go directly into the plant. It is the microorganisms that process, transform, and present the nutrients to the roots. If this processing system is not working, even the highest quality nutrient solution will not yield the desired results.

Therefore, it is not enough to feed the plant – the soil must also be fed. More precisely, the microorganisms living within it. If they are active, the cycle works: the soil provides nutrients, the plant returns organic matter, and the cycle continues.

How to keep your soil microbiology active?

The three most important factors are pH, oxygen, and nutrients. In acidic soil, most beneficial bacteria and fungi cannot function – so adjusting the pH is fundamental. In compacted soil, there is not enough oxygen, so loosening and maintaining proper structure are also crucial. Finally, regular, balanced nutrient supply ensures that the microorganisms also have their fuel.

The soil is alive not because of what is in it – but because of what is working within it. And this is the difference between a good garden and a struggling garden.