Did you know that there are millions of soil microorganisms in just a handful of healthy garden soil? Soil microorganisms exist in large numbers in the soil as long as there is a carbon source for energy.

The microorganisms living in your soil – including protozoa, fungi, bacteria, arthropods, and beneficial nematodes – are essential to keeping soil fertile so that plants can grow. Though too small to be seen by the naked eye, they work together to power the nutrient cycle that plants need to grow.


Courtesy of Ecoplexity.org

Plants can’t feed on soil organic matter (dead leaves, plants and animals) directly, as animals do. They need this material to be broken down and bio-chemically converted into simple forms that are microscopic and water soluble so the plants can take them up through their roots.

These are just some of the tasks that microorganisms perform:

  • Decompose soil organic matter, such as leaves and minerals.
  • Extract and convert nutrients from the decomposed material.
  • Provide the plant with nutrients, such as nitrogen and phosphorus, in a converted and plant usable form.

Chemical fertilizers are not an effective substitute for a thriving microorganism population. While chemical fertilizers are already synthetically converted to a plant usable form, they do not supply bio-chemical compounds, metabolites and exudates which are part of the healthy interaction between plant roots and microorganisms.

Carbon is the preferred food of microorganisms. To boost the population and activity of microorganisms try adding a little carbon, especially in or near the root zone. The carbon to nitrogen ratio, C:N, is important to the conversion and availability of nitrogen in the plant root zone. Also be aware that soil microorganisms are mostly dormant when soil temperatures are below 55⁰ F.

Fortunately, it’s not hard to attract microorganisms. They somehow manage to find their way into soil naturally, and then it’s up to you to care for them. Nourish these tiny creatures with the basics: food, water, and air. Feed them soil organic matter by adding Great Big Plants Natural Compost Extract and/or compost, ensure that the soil stays moist, and keep it aerated, and they will keep doing their jobs.

Just remember that healthy soil is teeming with little creatures who simply need basic care to do what they’re genetically programmed to do: to power the nutrient cycle. If you keep these microorganisms alive and help replenish their population, in turn, they’ll help your plants thrive.

Contributed by Tom Thomas