How Compost Tea works

Compost Tea explained by our Staff

What is Compost Tea?

Compost Tea is a aerated liquid product that is brewed. Start with compost or vermicompost, add key ingredients including a variety of microbes like bacteria and fungi, brew in oxygenated environment for 24-48 hours to create a mix of beneficial microbes, this is Compost Tea. Add to soil by broadcast spraying, soil drenching, soil injections or spray on aerial parts of trees to increase soil biology so that plants form relationships with the microbes so they can uptake nutrients from organic matter in the soil that is otherwise not attainable.

Beneficial microbes derived from compost, vermicompost, and organic bio-stimulants ultimately assist with the conversion of organic to inorganic compounds that then become readily available to plants for uptake through their roots and alters the pH level of the soil. Aerobic bacteria make alkaline glues that hold sand, silt, clay, and organic matter together creating the basic building blocks of soil.  Alkaline glues help to form aggregates by clumping together smaller particles of dirt. Compost tea also creates a microbial balance that is fuelled by beneficial bacteria and fungi to help combat and reduce the indidence of plant pathogens, infections, and diseases within root zones and on foliage.

Plants produce simple sugars through photosynthesis.  Plants also need minerals to grow, which include but are not limited to Nitrogen, Phosphorus, Potassium, Magnesium, Sulphur, Sodium, and Iron.  Most of these minerals are found naturally in soils but need to be converted to a soluble form that plants can absorb. Plants invest nearly half of their sugars into the soil by releasing them in the form of exudates.  The exudates can target and attract specific microorganisms that naturally consume organic matter and mineral particles, turning them into soluble nutrients. When the microorganisms die or when larger predators feed off of the bacteria or fungi, the soluble nutrients become available to plants for absorption.  

Synthetic fertilizers are a quick boost of soluble minerals.  Unfortunately, synthetic fertilizers are ionized nutrients (salts) that can dehydrate plants and form a crust on soil surfaces when applied incorrectly. Problems can occur with synthetic fertilizers in that any product that is not absorbed by the plants will be lost through run off into our waterways, and/or destroy soil structure through over saturation resulting in the death of the soil microbial life.

Compost tea can assist in the remediation of contaminated soils by the conversion of hydrocarbons into carbohydrates. Fungal colonies composed of mycelium absorb petroleum-based products while producing peroxidases that break the carbon-hydrogen bonds found in hydrocarbons, essentially forming carbohydrates.  Some bacteria also make enzymes to decompose organic matter or pull mineral nutrients from sand, silt, clay, and organic matter. Some of these enzymes can insert heavy metals into carbon structures and others can pull toxic chemicals apart.

Why use Compost Tea Canada™?

Compost contains a plethora of beneficial microorganisms including: bacteria, fungi, protozoa, and nematodes.  When the compost is exposed to water movement and aeration, the microorganisms that are attached to the compost compounds can be gently extracted.  With the help of several added ingredients acting as a food source, the microorganisms will multiply at a quick rate which ultimately, exponentially increases the population of microbial life in the solution in a very short amount of time.  The greater the microbial diversity in the compost, the greater the microbial diversity in the tea.  It is this microbial life and diversity within compost tea that increases the soil biology resulting in a healthier soil food web, optimizing the soil for plant growth.  

Compost Tea Canada™ has developed a range of customized soil amendment products formulated to promote a favourable biological environment within soils surrounding roots and/or on the foliage of plants including agricultural crops, ferns, flowers, herbaceous plants, mosses, shrubs, sod, and trees. 

Some helpful videos from Dr. Elaine’s Soil Food Web School

Why do we want a healthy soil food web?

Vegetation takes advantage of symbiotic relationships between specific bacteria and fungi that directly or indirectly convert organic minerals (like Nitrogen, Potassium, and Phosphorus + other minerals) into inorganic minerals in the soil solution which then becomes soluble for vegetation absorption. Bacteria and fungi benefit from the sugars released by the plant roots that attract microorganisms.  This will ultimately decrease or even terminate in some cases the use of synthetic fertilizers, herbicides, and fungicides. 

What do bacteria and fungi do?

Bacteria and fungi make up the base of the soil food web. Most aerobic bacteria are beneficial to plant growth.  Not only do they play a role in mineral conversion, but they also compete with disease organisms for food, space, and infection sites on plant surfaces as well as becoming food for macro-organisms like protozoa and nematodes (which in turn attract larger organisms like worms and beetles that help to aerate and continue the soil food web).  When bacteria die, they release soluble minerals and nutrients for vegetation uptake. Like bacteria, fungi compete well with disease organisms.  Different plants/trees will require either a more fungal based or bacterial based tea because the microbes control nutrient cycling in the form of the available nutrients.  Most trees do not do well with nitrate because nitrate and nitrite tend to promote disease conditions along their roots.  Fungi will produce metabolites that help lower pH and increase ammonium which is more of a requirement for trees.  Fungi are a major holder of calcium, retainer of nitrogen, phosphorus, sulphur, calcium, iron, etc.  Fungi help to build soil aggregate structure and improve water-retaining capacity.

How do we brew Compost Tea?

Depending on your needs, we concentrate on producing aerobic compost tea using our vermicompost (worm castings) or high fungal compost as the primary ingredient.  The compost, along with several added ingredients, will be steeped in an aerated compost tea brewer for between 24 to 48 hours.  Under an ideal aerobic environment, the complex set of organisms will feed off of the specific ingredients and multiply very quickly in this time. Since we control the ingredients for the tea, we can create recipes for targeting specific microorganisms and therefore target the requirements for specific plants, trees, and crops from both a foliar and root perspective.  We can also create teas to change soil structure, composition, and amend contaminated soils.

History

Compost tea has been in use since at least as far back as the ancient Roman Empire.  Evidence shows that during these times, teas were produced in large vats aerated by stirring the liquid occasionally.  Since then, compost teas have always been produced with extremely varying results including the loss of the vegetation that was meant to show an increase in health from using the compost tea.  This was most likely due to the compost tea going anaerobic causing an influx of harmful, disease causing bacteria to populate the compost tea which out-compete the beneficial bacteria in the soil. In the early 1990’s, the science behind compost tea began to advance.  Karl Rubenberger invented the first industrial scale bioreactor (brewer) for aerobic microorganisms called the Microb-Brewer.  Rubenberger brought his brewer to Dr. Elaine Ingham at Oregon State University in 1993.  She began to study the reasons why creating compost tea using this machine would yield better results. Since 1993, Dr. Ingham’s career has been involved with studying soil biology, compost, and compost tea.  Based on over four decades of research, Dr. Ingham created the Soil Food Web approach in repairing the fundamental biological processes in soil instead of using chemicals and fertilizers.