Introduction: Worm Tea and Castings Vermicompost Bin

About: Mechanically inclined electronics technician and software developer.

Worm castings and tea are great for your plants and garden (Wikipedia).

My dad traveled to New Zealand and saw these bins for sale there, but could not find them here in the states. So, we have recreated them here. This one is made from a 32 gallon wheeled trash can and provides a spout at the bottom for draining the worm tea and a port for removing castings at the bottom of the compost.


(Note: links are for reference and do not mean an endorsement of store or product.)

1 - 32 gallon trash can (link)

1 - 1/2 inch brass hose bib (link)

1 - 1/2 inch PVC female adapter (link)

1 - 2 inch neoprene washer

8 - 2.5 inch plastic louvers with screen mesh (link)

1 - 4 inch ABS screw out deck plate (link)

1 - milk crate

1 - 3 foot x 3 foot window screen (without any tears)

Step 1: Step 1: Install the Drain

Buying a brass hose bibb may seem like overkill, but it was cheaper than any other plastic quarter-turn valve.

Start by drilling a 3/4 inch hole on the front ("curb side") of the bin far enough from the bottom so that the valve will not hit the ground, about 2 inches from the bottom. Screw the hose bibb into this hole. (Should be a tight fit.)

I really do not want this to leak worm tea from here, so I may have done a little extra sealing.

Cut a hole in the 2 inch neoprene washer just big enough for the hose bibb threads, apply a small bead of silicon around one side, and placed it on the inside of the bin.

Use a 1/2 PVC adapter as a nut for hose bibb. Again, I placed a small amount of silicon on the threads and tightened it down, pressing down the washer and smoothing out the silicon.

Step 2: Step 2: Make the Milk Crate Fit

A milk crate will be used to support a screen, creating a reservoir for the worm tea to drain into and to hold up the worms and their food. The crate will rest on the wheel wells in the back of the trash can, and all the way down to the bottom at the front of the can.

Start by creating a rough template of the inside of the bin at top of the wheel wells.

Turn the milk crate upside-down and place your template on top to find out what parts you need to cut away. On mine, it was the middle section for the front. But, be sure to leave the corners the full length and intact. For the back, I needed to leave about two inches of the corners on the crate to rest on the wheel wells. You will need to cut of parts of the sides to fit over the wheel wells.

Step 3: Step 3: Install the Castings Port

The worms will start at the bottom when you first add food scraps and work their way up, eventually filling the bin. Or, you may want to get some of the castings on the bottom.

Place the 4 inch port on the inside of the bin just above the milk crate and mark a spot on the bottom of the inside of the hole. Drill a small hole here so that you have a reference point from the front of the bin.

Mark out a hole just big enough for the port to fit in. (Again, should be a snug fit.) I used a rotary tool with a hole-saw bit to cut this out.

Place the port in the hole to check the fit and mark the location of the six mounting holes.

Remove the port and drill 1/16 inch holes at each location.

Apply a small bead of silicon around the back of the port ring and around each mounting hole.

Reinstall the port and secure with the six screws.

Step 4: Step 4: Install Vents

Using a hole saw, cut out two holes on each side for the louver vents. I installed mine 1.5 inches from the top and 1/4 of the bin's width from the sides (four inches for my can).

Simply press in the vents. No need to seal with silicon because these are made to leak anyway.

Step 5: Step 5: Install the Screen Over the Reservoir

This part is important and cannot be skipped as it keeps the worms from falling through to the bottom.

Place the sheet of window screen over the top of the milk crate so that it lays flat(ish) and reaches all areas inside the bin, with the extra coming up the sides. (Easier said than done.)

Once I had the screen in place, I used a hot glue gun to tack down the screen to the sides of the bin.

Trim off the screen about two to three inches above the milk crate.

Use the foil tape to secure the screen to the sides of the bin. There should be no gaps anywhere along the sides for the worms to escape.

Cut the screen away from the opening of the castings port. Apply silicon through the screen to the side of the bin to seal around the port.

Step 6: Step 6: Install Worms and Compost Material

Add some vegetable scraps and red wigglers to your new bin. Keep piling food on top!

The milk crate supports the screen and provides a reservoir for the worm tea to drain into which can be collected using the spout. The worms and their food stay on top of the screen and milk crate. As the worms work their way from the bottom to the top, they will leave behind worm castings which can be collected from the port in the middle of the bin which was placed just above the screen.