Make Your Own Aerobic Worm Tea Brewer

Plants love fresh aerobically brewed worm tea. Just soaking the vermicompost for 48 hours is not going to give you all the results possible from worm tea. You’re missing out on most of the good stuff with that method.

Aerobic worm tea is at it’s nutritional best within 6 hours after the brewing process finishes. The beneficial microogranisms only remain viable that long. Once all the oxygen escapes the tea it becomes anaerobic which means that harmful bacterias are present and growing.

The cost of a compost tea brewer can be anti-budget friendly. No problem. You can make your own for $20-$30 depending on prices in your area and the stores you have available. The only tools you’ll need once the materials are gathered is a utility knife, a drill and  a 1/4″ drill bit.

In addition to a bag of vermicompost (worm castings), you’ll also need a jug of liquid fish, water soluble seaweed and some unsulphered molasses. Why? Well, commercial worm growers feed their worm nothing but paper and cardboard because its cheap food. This gives you nothing but nitrogen as plant food from your worm castings. Adding liquid fish and seaweed boosts available nitrogen along with rounding out your nutritional soup with some potassium and potash. The molasses feeds all those lovely beneficial microbes.

Your list of materials:

  • 5 gallon bucket with lid ( sometimes free from bakeries & restaurants)
  • 1 gallon paint can strainer sock (come in packs of 2)
  • Several feet of small aquarium tubing
  • 2 aquarium line t-splitters
  • 2 small aquarium bubbler stones (2″)
  • 2 medium aquarium bubbler stones (4″)
  • dual line aquarium pump
  • a piece of plastic twine about 12″  long

You could run around town to gather this stuff, or you could just hit Walmart (or a similar big box store) and get it all in one stop.

The worm tea recipe:

  • 4-5 cups of vermicompost
  • 1/4 cup molasses
  • 1 tablespoon of seaweed
  • 2 tablespoons of liquid fish
  • 4 gallons of water

Do not use chlorinated tap water without letting the chlorine dissapate. Well water, rain water and pond water are great as they are. To get rid of the chlorine that is harmful to beneficial bacteria and microorganisms that worm tea can provide your plants, let the bucket of plain water sit in the sun for a minimum of 1 hour.

The worm compost and small bubbler rocks go into the paint strainer sack. Everything else you just dump in the water. Let the brewing process run for at least 24 hours, but up to 48 is fine too.

For more effective worm tea you need oxygen and motion. Active microbes die within 24 hours after brewing.Putting your inexpensive worm tea brewer together is really simple. I built one myself recently following directions from a page I located online. The tea recipe above is awesome stuff! It grew tomato starts for the backyard garden that make those from a garden center look puny.

Rather than reiterating the great instructions I followed, visit this page to use the directions I did. And by the way, the nylon twine isn’t included there. He left out how to anchor the bag of vermicompost. I used plastic garden twine I found in the cupboard. Tied the paint strainer closed with one end, threaded it through the hole in the top and secured it to the bucket handle. You will get better oxygenation if the sack of worm castings is suspended in the bucket rather than sitting on the bottom.

Note: You need to clean your lines, bubbler stones and the paint sack after each brew. There shouldn’t be much if any worm tea in the tubing – if there is, blow it out. Put the stones and the bag to soak in vinegar for at least 8 hours to clean and sanitize it. Old worm tea becomes anaerobic and harmful organisms move in where beneficials once were.

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  • dan says:

    Hi, Can the brew be kept for longer with aeration and regular feeding

    • Tammy says:

      Hi Dan,

      Yes you can keep it alive longer by leaving the aeration running. Not so sure about feeding it and keeping it good long term. Not that it’s not possible, but how much should you feed it is the question. Too much would be as wrong as too little, and I always use mine all up within 2 days. Perhaps someone with the answer will add to the conversation here.

  • terry says:

    Great read thanks.Big thanks again.


Tammy Clayton

Contributing Writer at Garden Culture Magazine

Tammy has been immersed in the world of plants and growing since her first job as an assistant weeder at the tender age of 8. Heavily influenced by a former life as a landscape designer and nursery owner, she swears good looking plants follow her home.