The Little Black Soldier Fly Revolutionizes Composting

The Little Black Soldier Fly Revolutionizes Composting

Of all the insects we encounter, the fly may be one of the most annoying ones that we encounter in our day to day lives. However, the black soldier fly isn’t in the same category as the common house fly.

What Is A Black Soldier Fly?

A black soldier fly (Hermetia illucens) don’t actually look like the flies we swat at. In fact, they are quite different. They don’t buzz around, they won’t bite, and when the black soldier fly larvae is fully grown, it looks more like a black wasp (minus the stinger, of course), but more slender. Some would even go so far as to say they are pretty!

Black soldier fly.

The black soldier fly life cycle follows the traditional insect cycle. The eggs will incubate anywhere from 4 days up to three weeks. Then the eggs hatch, producing a larvae that is both wingless and legless. The hungry little grub feeds on massive amounts of fruit and vegetable waste very quickly.

Because these little creatures can enhance the decomposition process very quickly, many people who have compost bins will use the larvae to speed up the process exponentially.

The larvae stage lasts only about 10 days and then they mature into pupas. The pupas leave the area where they were feeding and burrow into the ground. After another 10 days, they will emerge from the ground as a winged adult. The winged phase is all about mating. The female black soldier fly will search for the best place to lay her eggs, which can be anywhere between 400 to 900 eggs!

How To Make A Black Soldier Fly Bin

As previously mentioned, you can use the larvae for compost, but you can also use the grubs to feed your animals like chickens, lizards, and even fish. Unlike a worm bin, the black soldier fly bin doesn’t require bedding and the larvae can even self-harvest by crawling right into a bucket that makes it easy to feed to your farm animals, or work into your compost bin.

What’s interesting is that if you have 100 pounds of food waste (vegetable and fruit peels, coffee grounds, tea leaves, and other kitchen waste), you could end up with 20 pounds of large black soldier fly larvae in the prepupae stage that is ready to transition into flies, or become your animal’s dinner.

To create one of these bins, you could either purchase a BioPod Plus unit. However, if you like DIY projects, you can make your own compost bin for black soldier flies.

To make your own, you can follow these steps!


For this project, you will need:

  • 1" Uniseal
  • 1.5" hole saw (For uniseal hole)
  • 15cm of 1" pipe
  • 1m of 1" black pipe
  • 1mm drill bit
  • 1x 1" 90° elbow
  • 1x 1" T piece
  • 1x 3cm screw
  • 20cm of wire
  • 5L of expanded clay balls
  • Baking flour
  • Corrugated cardboard (any box)
  • Drill
  • Food waste
  • Garden tray
  • Large bucket with lid
  • Screwdriver
  • Small bucket with handle
  • Water butt sized drill bit
  • Water butt tap
  • Zip ties

Step 1. Choose Your Bin

The bin you choose for your fly bin is going to be dependent on how much food waste your home tends to generate. If you generate a lot of waste, you will want to use a large bucket with a lid. This will allow you to throw away all of your waste, and the tight fitting lid will be essential for keeping the larvae inside the bin.

Once you’ve chosen your bin, drill a hole for your 1 inch uniseal. This will be the hole for the exit pipe. Ideally, this is where your larvae will exit the bin once they are ready to move onto the next stage.

Step 2. Fit The Exit Pipe

Once you’ve drilled the hole, you’ll need to insert the uniseal into the hole and then insert the T-pipe. If you can’t find uniseal, feel free to use a bulkhead fitting or drill a hole that will hold the pipe in place.

Step 3. Installing The Track For The Grubs

When the grubs are ready to pupate to the next stage, they are going to want to leave the food matter. You will want to install a “ramp” for them to crawl up and out. This ramp can be made from a pipe or tube that has been cut in half so that it looks more like a gutter.

Use zip ties to attach the pipe to the side of your bucket so that one end reaches the bottom of the bin and the other end is connected to the T-pipe. This will ensure the grubs make it to the exit.

Step 4. Attach A Drain

Attach a drain to the bottom of the bucket so that the liquid produced from the broken down vegetation will have a way to exit the bucket. You can either use the liquid you collect from the drain as a fertilizer (dilute this liquid 50 parts water to 1 part liquid), or simply dispose of it. 

Add a layer of rocks or clay balls at the bottom of your bucket so the liquid has somewhere to drain and keep the grubs from drowning.

Step. 5. Finishing Up

Now that your system is set up, you will want to add the final touches:

Attach a 90 degree elbow onto the pipe that is on the outside of the bucket. Then, drill a small hole on the top of the elbow and screw the screw into it. This is going to hold your collection bucket in place.

Fill this bucket half way with flour. This will act like dirt for the grubs to burrow into. It will also dry the grubs and prevent them from crawling away.

Inside the bin, stretch a piece of wire from one side of the bin to the other. Clip a piece of cardboard to it with a clothespin. This is where the female flies will lay her eggs.

Fly farm box.


Black soldier flies aren’t the pests like the common house fly. You can cultivate them so that they’ll be useful for composting or as food for your critters. We hope this guide was helpful and be sure to leave us a comment below to let us know what you intend on doing with your flies!

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