How to Build a Compost Tea Brewer and Brew Tea

I had a free 55 gallon barrel that I decided to turn into a compost tea brewer. Compost tea is a great way to magnify your compost by breeding the beneficial microorganisms and spraying them on your plants. Plants sprayed with high quality compost tea will be healthier, less affected by pests, and produce better fruits and vegetables.  

Tools Needed

  • 1.25 inch hole saw bit and drill
  • Skil saw with wood blade
  • Pipe wrench

55 Gallon Barrel

Materials Needed

  • 55 gallon poly barrel
  • 1.25 inch brass bulkhead fitting
  • .75 inch brass hose bib
  • 1268 GPH Pump
  • Tea Lab Aeration Hose
  • Thread seal tape
  • Tea Lab mesh bag

Hole Saw Bit, Spigot, Bulkhead Fitting

  1. The first thing I did was cut the entire top off the barrel. I used a skil saw with a wood blade on it. This may not be the best way to do it, but it worked. It did make tons of plastic shavings to clean up, so do this on concrete. Once the top was cut off, I could flip it over, and it made a perfect cover for the barrel.

Top cut off barrel

  1. Next, I drilled a 1.25 inch hole near the bottom of the barrel. I used a 1.25 inch hole saw drill bit.

Hole Saw Cut

  1. I reached down in the barrel and screwed in the bulk head fitting so the threads point out, with one of the rubber gaskets inside.
  1. I added the other rubber gasket to the outside of the bulkhead fitting and screwed the nut on the end, gently tightening with a pipe wrench. Be careful not to overtighten, as it can break the barrel and cause a leak.
  1. I added thread seal tape to the spigot.
  1. Screw the spigot into the bulkhead fitting. I hand tightened this and with the tape it did not leak.

Spigot Installed

  1. I chose a place upslope from where I planned to spray that was close to water and electric. I leveled the area and added cinder blocks for the barrel to sit on.

Platform for Compost Tea

  1. I added the plastic aeration hose, and hooked it up to the pump.

Aeration Hose

  1. I ran an extension cord to the pump.
  1. The brewer is ready. Add water. If you have well or rain water, aerate for 20 minutes before adding compost and ingredients. If you have city water, aerate for 24 hours to off gas the chlorine.

Filling the barrel

  1. Add finished compost to the sealed mesh bag, and put into the water. Hang with a clip.

Clasp to hold bag of compost

  1. Add whatever food you want to supply the microorganisms and your plants. I used a cup of molasses and liquid kelp.

Compost Tea Ingredients

  1. Then aerate your brew based on the water temperature.  
  • 80 degrees: 12 hours
  • 70 degrees: 24 hours
  • 60 degrees: 36 hours
  • 50 degrees: 48 hours

Compost Tea Brewing

  1. If the brew smells bad, do not put it on your plants, it has gone anaerobic. If it smells good and earthy, great, put it on your plants. Once the brew is done, use it all immediately.

~ Phil Williams

Phil Williams is a permaculture consultant and designer and creator of the website  He is also the author of numerous books, most recently, Fire the Landscaper and Farmer Phil's Permaculture. His website provides useful, timely information for the experienced or beginning gardener, landscaper, or permaculturalist. Phil's personal goals are to build soil, restore and regenerate degraded landscapes, grow and raise an abundance of healthy food of great variety, design and install resilient permaculture gardens in the most efficient manner possible, and teach others along the way.

This is a companion discussion topic for the original entry at

Hi Phil - thanks for this article; I've been wanting to set up a compost tea brewer, and now you've given me the step-by-step on how to do it.  Can you provide info on where/how to get the Tea Lab aeration hose & bag? Also, any specifics on the pump (make, model, ?)



The link below should get you everything you need. Happy brewing!

Wow, great link for compost tea stuff - thanks, Phil!  I can't wait to start brewing…

Hi Phil,
What kind of biology are you focusing on with your tea brews? Do you have a particular percentage you are shooting for, Bacteria vs Fungi? It is my understanding that most garden vegetables need a 50-50 bacteria -fungi ratio. Certain vegetables require higher percentages of fungi such as tomato's, garlic and strawberries.

Do you have any recommendations on how to vary the food you are using in your tea brew to tailor the tea to the different ratios.

Are you using a microscope to test your tea brews? I have been making compost extractions and tea for several months now and I'm looking for information on specific foods to brew the different kinds of biology.

I am currently brewing small batches in a 5 gal bucket, these brews being used on greenhouse veggies.
I have a 30 gal cyclone brewer I bought that will be starting to use to make tea for my fruit tree orchard and to spray on my pastures once they start to green up this spring. 



Gardeners should use compost tea. They are the best feed for your garden plants.If you put a lot of "greens" into the tea, the nitrogen content can be so high, that it would burn the plants. Ensure 10 parts with one part compost tea. This 10:1 would dilute nutrient level at easily absorbable level.Spread the leftover in your garden, or put it back into compost bin for later use.These nutrients while sprayed on leaves are easily absorbed.
As for the stinking , just check this article which says bleaching the inside of your bin atleast twice a month and cleaning it with soap and water after emptying would help you get rid off the stink. It also says leaving a cup of red wine vinegar beside the bin would avoid fruit flies.