What is Compost Tea and How to Use It
The Short Answer: Compost tea is a liquid made by steeping finished compost in water to extract soluble nutrients and beneficial microorganisms. It works more like a biological soil amendment than a traditional fertilizer, introducing and supporting the beneficial microbes that break down organic matter and make nutrients available to plants. Apply it as a soil drench or foliar spray to support soil biology, nutrient uptake, and overall plant health.
Most gardeners are familiar with compost as a soil amendment. Compost tea takes that a step further by multiplying the living biology in finished organic matter into a liquid that can be applied directly to soil or plant leaves. When done right, it is one of the most effective tools for building a healthy soil ecosystem.
What Is Compost Tea?
A Liquid Biological Amendment
Compost tea is not a fertilizer in the traditional NPK sense. It does not deliver a concentrated hit of nitrogen, phosphorus, or potassium. Instead, it draws living microorganisms and nutrients out of compost and into water, creating a liquid that supports the soil food web. As the University of Connecticut Extension explains, compost tea is used to provide nutrients for foliar or soil application and as a supplement to help build beneficial microbial populations.
The goal is to support soil biology, not replace it. When beneficial microbes from compost tea are introduced to garden soil or sprayed on plant leaves, they help break down organic material, cycle nutrients, and create an environment where plants thrive. Think of it as a way to amplify what healthy compost already does, concentrating the microbial life into a liquid form that gets to work immediately.
How It Differs From Regular Compost
Regular compost improves soil structure and adds organic matter over time, while compost tea turns that biological activity into a liquid that can be applied directly to soil or leaves for faster results. Think of compost tea as an addition to your soil health routine, not a substitute for regular compost inputs.
Aerated vs. Non-Aerated Compost Tea
The Two Main Types
There are two main methods for making compost tea. Understanding the difference helps you choose the right approach for your setup, though for most home gardeners and growers, the non-aerated method is the more practical and accessible option.
Non-aerated compost tea is made by steeping compost or a biologically correct liquid amendment in water and stirring regularly without adding an oxygen source. It is simple to set up, requires no special equipment, and still produces a biologically active liquid that can be used as a soil drench or foliar spray. The Dr. JimZ compost tea method uses this approach, and when made with a high-quality base like Chicken Soup for the Soil®, it delivers impressive results without the complexity of an aerated system.
Aerated compost tea uses an aquarium pump or air bubbler to introduce oxygen into the water while the compost steeps. Aerobic conditions support certain beneficial bacteria and mycorrhizal fungi, but this method requires more equipment and closer attention to the brewing process. Results can also vary more depending on water quality, temperature, and timing.
Why Compost Quality Matters More Than Method
Regardless of which method you use, the quality of the inputs has a major impact on the finished tea. Compost made from a diverse range of organic materials or high-quality worm castings will produce a richer, more biologically active tea than low-quality compost. Start with the right ingredients, then choose the brewing method that makes the most sense for you.
How to Make Compost Tea
The Dr. JimZ Method
The simplest and most effective way to make compost tea is with Chicken Soup for the Soil®. It already contains everything needed to produce a biologically rich tea without additional additives like molasses, minerals, seaweed, humic acid, or soluble kelp.
Here is the process:
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Step 1: Fill a 5-gallon bucket with water. Add half a gallon of Chicken Soup for the Soil® to 4.5 gallons of water for a 1:9 ratio.
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Step 2: Add a handful of good quality soil or pure worm castings as a microbial starter.
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Step 3: Stir the mixture and place the bucket in a warm location. Warmth is the most important factor for microbial activity.
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Step 4: Stir daily, or more frequently if possible. As an alternative, add one cup of 3% hydrogen peroxide to the bucket.
Fermentation time depends on temperature. At 80 to 90 degrees the tea is ready in three days. At 70 to 80 degrees, plan for four to five days. Below 70 degrees, allow about a week. The tea can be used early but will be more effective once fully fermented.
Use It Fresh
Compost tea contains living microorganisms, so it is best used fresh once brewing is complete. The Dr. JimZ method focuses on multiplying good microbes during fermentation before applying the tea to soil or leaves. Once the tea is ready, apply it soon after brewing to get the most benefit from the active microbial population.
As a general compost tea brewing tip, avoid heavily chlorinated water because it can interfere with beneficial microbes. If using tap water, let it sit out before brewing so some chlorine can off-gas naturally.
How to Use Compost Tea
As a Soil Drench
Apply compost tea straight to the ground around the base of plants to introduce beneficial microorganisms directly to the root zone. This method supports the soil food web, improves nutrient cycling, and helps plant roots access nutrients already present in the soil. Use it in garden beds, around trees and shrubs, or anywhere you want to rebuild or support biological activity.
As a Foliar Spray
Compost tea can also be applied as a foliar spray directly to plant leaves. When used this way, dilute it at a ratio of 1 part tea to 10 parts water before spraying. The beneficial microorganisms in the tea occupy the leaf surface, creating what is known as biological exclusion. This may help make it harder for unwanted bacteria and disease-causing organisms, including common issues like powdery mildew, to develop.
Apply foliar sprays early in the morning or in the evening to avoid leaf burn from sun exposure and give the tea time to settle on the leaves. The University of Arizona Cooperative Extension notes that organic growers use compost tea to support plant health, deter pests, and reduce reliance on chemical additives.
Timing and Frequency
Compost tea can be applied throughout the growing season. Many growers apply it once or twice a month as a soil drench and as needed as a foliar spray when plants show signs of stress or disease. It works well alongside regular compost inputs and other organic matter applications as part of a broader soil health routine.
The Benefits of Compost Tea for Your Garden
Compost tea is one tool in a broader soil health system. When made with quality inputs and applied correctly, it can support:
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Increased biological activity in garden soil and the root zone
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Better nutrient uptake through a more active soil food web
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Improved soil structure over time as microbial populations grow
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A natural defense on plant leaves against disease pressure
The Dr. JimZ Approach
Dr. JimZ has spent over 50 years developing biologically correct fertilizers built on the same principle that makes compost tea effective: feed the microbes and the microbes feed the plant.
Chicken Soup for the Soil®
Chicken Soup for the Soil® is the foundation of the Dr. JimZ compost tea method. It is a biologically correct liquid soil amendment that already contains all the nutrients and trace minerals needed to produce the best compost tea without additional additives. Use it straight as a soil drench, diluted as a foliar spray, or brewed into compost tea for an even more concentrated biological boost. It works on all soil types and builds on itself with every application.
When you brew Chicken Soup Compost Tea™, you are multiplying the beneficial microorganisms before they go into the soil or onto the plant. The microbes ingest the nutrients in Chicken Soup for the Soil® as they multiply, and their biological output is what makes the tea so effective.
Shop Chicken Soup for the Soil® and find the full compost tea recipe at drjimz.com to get started.