All About Aerated Compost Tea / Aerated Worm Tea


I am sure you might have come across directions, suggestions, equipment, and warnings about compost tea and worm tea on the internet. I have composed this article with in-depth research on making this tea, its benefits, potential downsides, and the best practices to make maximum use of it. 

What is Compost Tea?

Compost tea is nothing new. Previously, it was made by suspending a bag full of compost or manure in a bucket filled with water. Then, it was left for a few days until the water became darkened. The dark color of water indicated that the tea was ready to be used as nutrient-rich water for plants. 

For instance, people collected chicken manure in wine casks and diluted it with water (usually rainwater). Once stirred up, the compost tea was ready to water a crop. However, today, this isn’t a recommended practice. 

The solution prepared with the above technique smells awful and is no longer known as tea. Instead, anaerobic leachate serves as a house of undesirable anaerobic bacteria with potential pathogens, including E.coli and Salmonella.

The recommended tea has been known as Actively Aerated Compost Tea or AACT in recent times. This tea is made using a brewing technique. A container and chlorine-free water are used with wholly decomposed compost and an aeration system such as a multi-outlet aquarium pump with a couple of air stones that keep the water highly aerated.

You might see the use of additives in some recipes to encourage the growth of desired fungus and bacteria.
Usually, the processing time is not more than two days. Moreover, it is recommended that the compost tea is used immediately before microorganisms thriving in the tea use up the available oxygen supply.

Is Compost Tea Useful?

Well, debatably, many supporters believe AACT is beneficial. It has, no doubt, a lot more than just compost. For example, you can treat your plants with four times more microbes than simple compost with a well-made AACT. Furthermore, in AACT, the nutrients are adequately dissolved, it becomes much easier for plants to absorb them.

You can use unfiltered AACT as a soil drench, and you can easily use filtered ACCT as a foliar spray. Sprayed plants with AACT can absorb the tea through their vegetation, and theoretically, good microbes help limit certain diseases by attacking harmful microorganisms. You can also use it to simulate decomposition in a compost heap. 

Benefits of ACCT

Some of the significant benefits you can enjoy by using Actively Aerated Compost Tea include:

  • Increased Nutrient Cycle. The nutrient cycle is a necessary process that makes the nutrients in the soil available for plants. When you use AACT, you are not directly feeding the plant. Instead, you are feeding microorganisms in the ground that will convert the available nutrients easily into usable form by plants.
  • Addition of Useful Microbes. A typical well-made batch of AACT contains a good population of nitrogen-fixing bacteria, phosphorous and nitrogen-solubilizing bacteria, and many other valuable bacteria that help in stabilizing soil health.
  • Creates Soil Structure. Archaea and bacteria help soil aeration, whereas fungal hyphae help create soil aggregates. With AACT, you increase the biomass of your soil, which allows it with the water holding capacity.
aerated compost tea2

What are the Limitations?

There are, however, some detractors. The significant point is that the nutrient value of a compost tea batch is only a fraction of the nutrients present in a small amount of compost used for tea preparation; however, it spreads across a larger area.

Furthermore, you can undoubtedly generate a large population of microbes; however, you have little to no control over the type of bacteria from batch to batch. Moreover, there is a risk of building up pathogenic bacteria as well.

Best Practices for a Successful AACT Application

There are several ways for AACT application. Here, I will discuss the best practices for the successful application of AACT to get the most of it:

  • Always use high-quality compost. It means that your compost should contain fully-decomposed material. Also, make sure it has been hot composted as it helps kill pathogens. This needs to be taken care of, especially when using animal manure as a source of compost.
  • Avoid using additives as they may help increase the population of harmful microorganisms. The compost alone can brew a perfect tea when the steps are done correctly.
  • Ensure excellent aeration of the tea and use it right after the process is completed. Pathogens like E.coil and Salmonella are anaerobic microbes and can’t thrive in aerobic conditions.
  • The visual signs of a well-made tea are bubbles on the top, a coffee-brown color, and a sweet earthy smell.
  • Avoid spraying the tea directly to edible parts of the plants.
  • Don’t forget to thoroughly clean and disinfect the brewing equipment right after the competition of each tea batch.

The Right Process of Making AACT

You will find many ready-made brewing kits for AACT. However, I prefer the following DIY approach as it is economical and practical for most home gardeners.

Here are the step-to-step instructions on how to brew the right AACT:

  • First, take a 5-gallon bucket and fill it with 4 gallons of chlorine-free water – rainwater is the ideal one; however, well water is good too. If you are using city water, make sure to aerate it properly for a few hours in an open container to eliminate chlorine.
  • Now, aerate this water in the bucket with a double outlet aquarium pump connected with plastic tubing to two air stones in the water.
  • At this step, you need to add 1 cup of compost per gallon of water to the bucket. As you have taken 4 gallons of water, you will add 4 cups of compost. Use a pillowcase or stocking to put compost. It will reduce the need to filter the tea, especially if you want to spray it on the plants. If you add loose compost, put it in the bucket before adding water. However, if you have put compost in a pillowcase or stocking, squeeze it a couple of times to help water infiltration after adding it to the water bucket.
  • You will find a nutrient source to increase microbial activity in some recipes. However, we will use two tablespoons of sugarcane, maple syrup, sulfured molasses, or fruit juice. It will encourage bacterial growth. If you want to produce a fungal-dominated tea, use a similar amount of humic acid, kelp, rock phosphate, or fulvic. However, you need to check your tea for pathogens to add nutrients to the compost suspension for organic growers.
  • Teas that are bacterial-dominant encourage nitrogen-fixation in the soil. It also helps in insect resistance and suppression of certain diseases. These are better for annuals and vegetables. On the other hand, fungal-dominant teas help in accelerating the decomposition process, especially for woodier and more rigid materials. Such teas also aid in fighting against downy and powdery mildew. These are recommended for trees, perennials, and shrubs.
  • The brewing time is 24 to 36 hours. The ready-to-use tea would have a sweet earthy smell, a coffee-brown color, and bubbles on the top. Ensure your tea is away from the sunlight as UV rays can cause damage to the microorganisms. Keep it as close to the room temperature as possible for the best results.
  • This is the most crucial part of getting the best results from your hard work. You need to use the tea within 4 hours once the process is completed. It is necessary to use it before the microbes use up the oxygen source in the tea. You can apply it directly to the soil without filtering at a rate of 5 gallons for every acre. If using filtered as a spray, use it 10 gallons per acre. You can quickly dilute the tea 4 to 5 times the original volume while the benefits remain intact.
  • If you previously used chemicals on your soil, AACT is an excellent way to regenerate your soil organisms. However, it will take multiple applications before you rebuild the solid population.
  • The best time to apply it is early in the morning or evening to avoid UV light killing the microbes.
  • Dissaemble your brewing kit and immediately clean it with either 3% hydrogen peroxide solution or 5% baking soda.
Nitrogen Fixation

The Last Words

Actively Aerated Compost Tea could effectively strengthen your solid microorganisms and help with diseases and insect resistance. Even if your soil is rich in organic nutrients, AACT boosts decomposition and makes the nutrients available for the plants. In addition, they are easy to apply than solid compost and an excellent way to stretch a limited compost quantity.