What is Compost Tea-The Way to Healthy, Vibrant Plants

Compost tea

Many of us enjoy a good cup of tea from time to time but unless you are a serious organic farmer you may not know much about compost tea. Don’t worry it has little to do with your favorite cup of tea, instead this is beverage of choice for your rapidly growing gardens.  What you may not know is that compost tea is easy to make and use, no matter how serious of a gardener you are, and it has some major benefits for your carefully tended plants.

What is Compost Tea?

Compost tea is exactly what it sounds like. Just like you put water into a cup or container to brew tea, for this brew you are combining good quality organic compost with water and a small amount of molasses to make a tea. A fish aquarium pump is used to constantly aerate the tea until it is ready to use. This mixture is brewed for a few days, then strained. Once your tea is complete it is then sprayed directly on your plants and added into the ground.

Teas have been used on gardens for centuries, but not all of them have the same benefits as the aerated compost tea has and in some cases may cause harm to your plants or those who eat them.

Manure tea – Made from soaking manure placed in a piece of water permeable cloth, manure tea was used for many years and was at one time the standard for fertilizing crops. Concerns about E. coli being transferred to the plants have caused many farmers to steer away from the process.

Leachate – The liquid coming from your compost pile called leachate is not actually a tea and can be have harmful pathogens in it, making it not suitable as a compost tea.

Traditional Compost Tea – Made in a similar process to manure, tea compost is simply soaked in water without being aerated. Without oxygen for the microorganisms, the mixture can turn anaerobic. You will know this is the case if the mixture begins to smell bad. Anaerobic tea can actually harm rather than help your plants, so it is best avoided.

Aerated Compost Tea – Made from organic compost, a small amount of molasses and water which is aerated, this type of compost tea encourages the growth beneficial microbes. This type of tea has a number of benefits not only for your plants but also for your soil.

Compost Tea Benefits Your Entire Garden

One of the first questions that new gardeners ask is why not just put the compost directly on your garden? While this would seem to make a lot of sense, there are specific benefits that come from compost tea that make this method of feeding your plants a smart idea, especially for organic gardeners that do not use chemicals such as pesticides and fungicides.

Gardeners know that soil quality is essential for a healthy garden, especially if your goal is to garden organically. Compost tea, in addition to feeding your plants with a rich mix of nutrients also provides your plants and garden with beneficial microbes that can help fight disease.

When pesticides or other chemicals are used on a garden, not only are the pests killed off, but the beneficial organisms are killed off as well. Compost tea can help control disease and pathogenic organisms without chemicals by creating an environment that eliminates or crowds out the pests you don’t want in your garden. The tea contains good bacteria and fungi to help the decomposing process,and beneficial nematodes, which are predators that defend your garden from bad microorganisms that can harm your plants. When sprayed on the plant, the tea provides protective barrier of beneficial organisms that keep bad organisms away. Drenching the soil with compost tea improves soil structure, aids in decomposition, and creates a healthy environment where your plants that will grow more vigorously and be more resistant to disease and insect attack.

Getting Ready to Make Compost Tea

There are a lot of options available for gardeners who want to make their own compost tea. Whether you have a small farm, or a small backyard garden or even container gardening you can make your own easily at home.

In general, you will need:

  • A Good quality source of organic compost
  • A container to put your brew in (such as a 5-gallon bucket or for larger quantities a trash can).
  • Water
  • Molasses
  • Some sort of aerator, such as a fish tank pump.
  • Tubing and bubblers to connect between your pump and your container, (you may want a gang valve, 6 lengths tubes, and 3 bubblers depending on the size of a bucket you are using).
  • Something to stir with such as a stick.
  • Either some sort of cloth bag that will hold compost in but will let water circulate freely such as burlap or cheesecloth, OR a second bucket that you can strain your tea with a mesh strainer.

Alternatively, if you have a small garden or containers, you can also buy compost tea brewers that are all in one and allow you to brew smaller batches in a more contained setting. While completely not necessary, they are inexpensive and offer city gardeners a way to brew compost tea in smaller quantities and in smaller spaces.


– Compost is your most vital component of your tea and there are a few things you need to know before you go digging into your old compost pile in your backyard. Any compost that you use must be organic, the reason for this is that the same chemicals that kill off microbes in a garden can also kill off the microbes you are trying to cultivate in your tea.

In addition, compost must be mature, meaning that it is completely broken down and it has had time for the heat in the compost to kill off any pathogens or weed seeds that might be present. If you do not currently have any compost it is a good idea to read up more on how to create and manage a compost pile to ensure that you start with clean mature source for your tea.

If you do not have a compost pile, it is possible buy compost for this project, but you must be mindful of quality. Know your sources, for instance it is not advisable to buy it from another backyard gardener unless you are very clear about their gardening practices and the proper maintenance of their compost pile. Compost piles, not properly managed, can carry a host of diseases you will not want to introduce to your garden. Garden centers that have good quality organic compost in bags may be a good alternative if you are unable to have a compost pile and want to try to make compost tea for your small garden.

Water – Water should be free of chlorine, which means you can either use well water if you have access to it, or you can pour the water into the bucket and run the aerator with a bubbler for about an hour to rid tap water of chlorine.

Containers– The size of containers you use will depend on the amount of compost tea you wish to make. Keep in mind it brews in about 3 days and you must use it after it is done brewing. Choose a container that will accommodate the size of your garden.

Creating and Using Your Brew

Once you have collected your materials making compost tea is easy:

  1. Add compost until it reaches the halfway mark on your bucket or other container, making sure it is loosely packed. (You can also place it in a bag if you do not want to strain it at the end).
  2. Connect your aerator by connect tubes to pump, through the gang valve and into the bubblers and bury the bubblers into the compost all the way at the bottom of your container.
  3. Fill the bucket with your prepared water, within 3 inches of the rim.
  4. Start your pump
  5. Add an ounce of molasses and stir it in well (this is food for the organisms you are trying to cultivate).
  6. Continue to stir your tea during the 3 days it brews.
  7. Removed the compost (if in a bag) or strain the tea into another bucket using a mesh strainer.

You are now ready to use your compost tea. Be sure to use the tea as soon as it is finished brewing. You can either add your compost solids to your garden or put them back into the compost pile. Your tea can be used both as a spray for your plants and/or add it directly to the soil. For best results you might want to do both. Enjoy your strong healthy plants, it has been noted that not only do plants grow stronger and healthier with compost tea, they often produce higher yields and a healthier more flavorful produce!


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