How to Make Homemade Compost Tea

Compost tea is a natural fertilizer.

Compost tea is a natural fertilizer.

If you've been composting your scraps for at least a few months, you can use your compost to "brew" a nutritious and vitamin-rich fertilizer. Compost tea is organic and all natural, making it an effective and affordable alternative to commercial fertilizer blends. You can make your own compost bubbler using basic supplies from hardware and aquarium stores. If it's brewed correctly, compost tea is safe to use in your garden as often as every two weeks.

Items you will need

  • 2 5-gallon buckets, or one bucket and large watering can
  • 1 gallon mature compost
  • Aquarium pump
  • Gang valve to divide air supply into three streams
  • 4 or more feet aquarium hose
  • 1 oz. unsulfured molasses
  • 3.5 gallons water
  • Scissors
  • Cheesecloth or nylon stocking
  • 110-volt power source

Bubbler Setup

Cut three 12-inch lengths of aquarium hose. Attach one end of each hose to the gang valve.

Hook the gang valve over the edge of the bucket, with the hoses inside the bucket. Make sure the hoses are long enough to reach the bottom of the bucket.

Attach one end of the remaining aquarium hose to the pump. Attach the other end to the gang valve's inlet.

Fill the bucket with 3.5 gallons of water. If you are using city water, plug in the pump and let air bubble through the water for at least one hour before proceeding.

Add mature compost and molasses.

Brewing and Harvest

Let the mixture brew for two to three days. Stir vigorously a few times a day, to mix the compost and help microorganisms separate from compost particles.

Strain the brew through cheesecloth or a nylon stocking into the second bucket or watering can. Discard the remaining matter.

Sprinkle the foliage and soil around each plant in your garden with compost tea.

Wash your hands.


  • Use compost tea as soon as possible after brewing. Tea may lose its effectiveness as time passes.
  • If you brew your tea for longer than three days, add more molasses to boost bacteria populations.


  • Use only mature compost to brew tea. Mature compost is approximately 1/3 its original size, dark, crumbly, earthy smelling and has no strong odor.
  • If your compost tea smells strongly of ammonia, rotten eggs or anything other than earth, do not use it in your garden.
  • Commercial additives such as kelp, fish hydrolysates, humic acid, rock dust and nutrients may spur the growth of dangerous bacteria, including salmonella and E. coli (see References 4).

About the Author

An award-winning blogger, Jessica Blue has been promoting sustainability, natural health and a do-it-yourself attitude since graduating University of California, Berkeley in 2000. Her work, seen in a wide variety of publications, advocates an environmentally-responsible and healthy lifestyle.

Photo Credits

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