How to Make Compost Tea: 2 Methods

How to make compost tea

Once you’ve mastered starting a compost pile and applying compost to your garden, what’s next? If you’re itching to learn a new way to incorporate the benefits of compost into your garden, it’s the perfect time to learn how to make compost tea.

Compost tea is filled with a complex array of beneficial microorganisms and nutrients, and it’s quite simple to make at home.

What is Compost Tea?

Compost tea is a liquid that’s rich in nutrients and beneficial microbes. Just like other teas, compost tea is made by steeping a solid – finished compost – in water.

While herbal teas may calm your mind or energize your body, compost teas help enliven the soil and strengthen plants.

Quality Compost is Key to Quality Tea

Before we dive into the details of compost tea, let’s get an important fact out of the way. In order to end up with quality tea, you need to start with quality, finished compost!

Remember that compost relies on microorganisms to break down the input materials like food scraps, leaves, and straw. While there are some microbes naturally present in all environments, you can boost the number and diversity of organisms in your compost pile by applying an inoculant.

An inoculant delivers a dose of microbes to your compost pile. After application, these microbes multiply and start breaking down the material. Not only do inoculants speed the decomposition process, but they also add additional biology to the finished compost, and therefore to tea.

What are the Benefits?

Compost tea provides many of the same benefits as compost. When you add it to your plants, you provide them with a dose of nutrients as well as beneficial microbes such as bacteria and fungi.

When you apply tea, you’ll notice an improved soil structure and soil nutrient-holding capacity. Tea applications also increase the availability of nutrients in the soil. Therefore, plants can take up more nutrients, which leads to healthier plants.

Watering garden with compost tea

Additionally, tea helps protect plants against harmful pathogens. When you spray it onto plant leaves, the beneficial microorganisms compete with harmful organisms.

The result? Less pressure from diseases such as late blight and downy mildew.

One more benefit of using compost tea is an increased soil water holding capacity. When you apply tea, the soil holds more water, so you won’t need to irrigate as much. This can help you save water as well as time.

How to Make Compost Tea: Aerated and Non-Aerated Options

There are two main types of tea: aerated and non-aerated. If you want to make aerated tea, you must supply oxygen to your brew. On the other hand, non-aerated tea is made without oxygen.

Some microbiologists, such as Dr. Elaine Ingham, prefer aerated compost tea. This is because some harmful microbes only form in anaerobic environments.

No matter what type of system you use, make sure you use high-quality, finished compost. Remember, compost tea is not a way to get rid of low-quality compost, but rather a method to utilize the microbes and nutrients present in finished compost.

Important Notes When Brewing Tea

Unchlorinated water for compost tea

When making tea, use one quart of compost for every five gallons of water. It’s important to use unchlorinated water. You can use rainwater, or let tap water sit out for 24 hours to dechlorinate.

During the brewing process, aim to keep the temperature around 70ºF.

While you can make compost tea with only water and compost, you can also add additional amendments like seaweed extract and molasses.

Aerated Compost Tea Recipe

To make aerated tea, you’ll need the following equipment.

  • Air pump
  • Air stone (aquarium bubbler)
  • Plastic tubing
  • Bucket – five gallons or larger
  • Cheesecloth
  • Finished compost

After you’ve gathered your materials, follow these steps.

  1. Place one quart of compost in cheesecloth, and tie to secure.
  2. Place the air stone in the bucket and use tubing to connect it to the air pump.
  3. Fill the bucket with five gallons of water.
  4. Place the compost bundle into the water.
  5. Wait 24-36 hours, then remove the compost.

Non-Aerated Compost Tea Recipe

Unlike aerated tea, non-aerated tea is made in an environment without oxygen. To make non-aerated tea, you’ll need the following:

  • Finished compost
  • Cheesecloth
  • Bucket or tote – five gallons or larger

To make the tea, follow these simple steps.

  1. Place one quart of compost in cheesecloth, and tie to secure.
  2. Fill your bucket with five gallons of water.
  3. Place the compost bundle into the water.
  4. Wait three days, then remove the compost.

How to Apply 

Once you’ve made your tea, it’s time to apply it to your plants. Since compost tea is biologically active, aka full of life, it’s best to apply it within 24 hours of finishing brewing.

There are two main ways you apply tea: via foliar spray and as a soil drench.

Foliar Spray

To feed your plants via a foliar spray, simply place the tea in a sprayer and spray your plants until they are dripping.

Pro Tip: It’s best to do this during the evening or on a cloudy day, as plants are susceptible to sunburn after being sprayed.

By spraying tea onto your plants, you’re adding microbes directly to the foliage. This application method is particularly helpful in deterring foliar pathogens such as downy mildew and early blight.

Soil Drench

Another way to apply compost tea is to add it directly to your soil. You can do this by hand with a watering can, or via an automated fertigation system (essentially an irrigation system). 

When you apply the tea to the soil, you improve soil structure and provide the soil with a dose of beneficial microbes. These microbes, along with the nutrients in the tea, provide plants with a higher dose of necessary nutrients.

Other Types of Nutrient-Rich Tea

When you’re reading about compost tea, you might come across some other types of teas made for plants.

  • Plant tea: Made with recently cut plants such as comfrey and nettle.
  • Manure tea: Made with animal manure.
  • Worm casting tea: Made with worm castings.
  • Microbial tea: Made with specific formulations of microbes that are sold by a variety of manufacturers.

Get Brewing!

Now that you know the basics about compost tea, it’s time to try your hand at brewing some.

While you can get lost in all the studies about microbes and benefits of compost tea, the brewing process is quite simple. So, give it a try and let us know if you how it turns out!