Make your own compost tea brewer

Compost tea brewer
Photo: Simon Webster

Soil Foodweb has provided the following plan for a home-made brewer. I put it together in about an hour (not including shopping time). Total cost was about $250, with the main cost being the powerful pump ($195) and the tea bag ($35), both of which I bought from Soil Foodweb. If sourcing material from elsewhere to make a tea bag, make sure the mesh is no finer than 450 microns. The rest of the parts can be bought cheaply from hardware stores.

This 60-litre brewer can be used to make brews of 20 litres or 50 litres (or anything in-between, though sticking to round numbers makes it easy to measure out ingredients).

It is essential that the brewer is cleaned thoroughly using detergent after each use to prevent anaerobic organisms forming. The tea bag should be soaked in bleach and water for an hour then rinsed.

Parts:

  • 1 x 60-litre wheelie bin
  • 1 x 90-watt aquarium blower (minimum
  •  200 litres a minute)
  • 1 x 450-micron tea bag
  • 2m 20mm electrical conduit
  • 2m 20mm corrugated electrical conduit
  • 1 x 20mm elbow
  • 2 x 20mm joiners
  • 2 x snap-clips
  • 1 x rubber chair leg tip
  • 20cm clothesline or other plastic cord
  • Drill bits: 3mm and 25mm

Step 1. Drill a 25mm diameter hole in the front left corner of the lid, in front of the handle. This is where the vertical aerator pipe will sit. Using strong scissors or pruners, cut the lip out to open up the hole. This enables the lid to be opened with the pipe in place.

Step 2. Cut a piece of the 20mm electrical conduit so that it sits in the bottom left front corner of the bin, and sticks up above the lid about 150mm.

Step 3. Put a 20mm elbow on the bottom of the vertical pipe. Measure from the front of the elbow diagonally across to the back right bottom corner of the bin. This is where the horizontal aerator pipe will sit. The aerator pipe will go into the elbow about 20mm, and in the other corner will have a rubber chair leg tip on the end. Cut long and be prepared to trim, to make a snug fit.

Step 4. Drill a hole in the left rear corner of the bin, just below the lip, and the right front corner just below the lip. Thread clothesline plastic cord through the holes and tie knots to hold in place. Use snap-clips to hang tea bag from clothesline. The top of the bag should sit well above water level and be reasonably taut.

Step 5. Connect about 1.5m of corrugated electrical conduit to the vertical aerator pipe using a conduit joiner. Use another joiner to connect the other end to the pump outlet. (The pump outlet may need tape wrapped around it to ensure a snug fit.) Step 6. Drill two rows of 3mm holes in the horizontal aerator pipe. The holes need to be 20-25mm apart, and located at the 5 and 7 o’clock positions (if the pipe is sitting on the bottom at the 6 o’clock position.)

By: Simon Webster

First published: August 2013

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