Compost Tea: What is it and Why Producers Should Care

Viewers of Episode 1 of Faces of Food Season 3 watched as Illinois corn and soybean producer Doug Martin emphasized the importance of “trying different things” to improve soil health and grain quality.

“We’re trying to make that soil healthier by introducing more beneficial fungi, bacteria, things like that,” he says.

In addition to using cover crops and other unconventional farming methods, Martin also mentions something that may have left a few viewers scratching their heads: compost tea.

Hopefully, the Q&A below can answer the basics about compost tea and give some ideas about how to figure out if it’s right for you.

What is compost tea?

Compost tea is a liquid that’s “brewed” by mixing fully composted organic matter (manure, stalks, etc.) with water. It harnesses the beneficial fungi and bacteria in compost and converts them to a liquid solution that’s easily applied to your farm and is aerated to keep the aerobic microbes alive until use.

It’s not a fertilizer in the traditional sense of the word. Rather it’s a biological that provides the food that these microbes need to multiply and grow. These microbes then help break down organic matter in the soil and make important nutrients like P and K easier for crops to absorb and utilize.

The resulting microbe-rich liquid can then be easily applied to fields through a number of methods. Using compost tea helps distribute microbes on the field more efficiently, allowing a modest amount of compost to cover more acres.

The Martins brew their own compost tea on-site, combining different ingredients with ready-made additives available on the market.

What are the benefits of compost tea?

There are a range of benefits that come from applying compost tea to your acres. For starters, beneficial fungi and bacteria in compost tea help break down the organic residue, resulting in plant-ready nutrients. The result is healthier soil and root systems, as well as improved water retention and fertility.

Compost tea also helps activate nutrients in the soil so they are accessible to the plant rather than having anaerobic bacteria or bad fungi break them down and gas off the beneficial components into the atmosphere.

To summarize, the benefits of compost tea include:

• Higher nutrient levels
• Improved root growth
• Higher microbe diversity
• Improved plant health
• Higher crop yields
• Better soil structure

According to the Martins, compost tea helps improve soil health, produce healthier crops, and reduce the need to use synthetic fertilizers.

How is it made?

Compost tea gets its name from the fact that compost is often held in a mesh or cloth bag that’s submerged in a container of water, similar to how tea is brewed.

You need compost, water, a bag or basket to hold the compost, a plastic container to fill with water, and an aerator. Once you’ve filled your container with water, submerge your compost bag and basket and then start aeration.

The brewing process can take anywhere from 24-36 hours. It’s best to apply compost tea within a few hours of completing the brewing process while microbes are still active.

The optimal mix of compost ingredients and additives can vary depending on the soil, crops, and other factors. The Martins are continually experimenting with different formulas to match current needs and conditions.

How does compost tea relate to regenerative agriculture?

The use of compost tea is another tool that allows producers to manage inputs responsibly, one of ADM’s five principles of regenerative agriculture, which are based on Indigenous ways of land management and are adaptive to local physical conditions and culture.

Using biologicals like compost tea can help decrease the amount of nitrogen and other chemical fertilizers producers need to add to their acres without having a negative impact on yield.

Compost tea can also help improve overall soil health. According to Derek Martin, it can take about three to five years to rebalance soil nutrients after years of conventional farming.

How can I introduce compost tea in my operation?

As a first step, do some research into different compost tea brewing techniques and explore what kind of ingredients and additives might be a good fit. The next step is to start brewing and test your own compost tea on a few acres. See how it affects soil fertility, plant health, yields, etc.

Once you find a mix and method that works, you can scale up your compost tea production and start applying it to more acres. As the Martins explain, it’s an ongoing process of testing and learning. For them, the effort has clearly paid off.

Where can I learn more about compost tea?

There are a number of useful resources available online that offer more in-depth information about compost tea, from different ingredients to brewing methods to detailed analysis of the impact on plant growth and soil health.

Here are a few to help you get started:

The Compost Tea Brewing Manual – 5th Edition (Dr. Elaine Ingram, Soil Food Web)
Compost Tea 101 (University of Arizona College of Agriculture & Life Sciences)
Compost tea: Boost microbes to build soil health (Nebraska Farmer)
No-Till, Cover Crops Improve Soil Health for Increased Profits (No-Till Farmer)
Compost Tea: A How-To Guide (Rodale Institute)

Of course, it’s always wise to consult with a trained agronomist who can provide professional guidance before making compost tea an integral part of your operation.