black soldier fly harvester

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[ DIY black soldier fly larvae composting system ] Part One _ The Harvester

If you have never seen a black soldier fly or black soldier fly larvae, you can see them here, here and here. They are super composters that digest food waste at an amazing rate. Black soldier fly larvae are also self harvesting so you can collect them for use as chicken or fish feed.

There are four fundamental components to a black soldier fly composting system. So far I have only explored the harvesting part of the system, but I plan to post the remaining three parts of the system as I find solutions that work. Feel free to experiment with this design and let me know if you make any improvements. Contact me - resplore [at]

  1. harvester - allows mature larvae to naturally migrate out of the food waste
  2. drain - maintains optimum moisture levels in the bsfl bin
  3. egg laying zone - the adult black soldier flies prefer to lay their eggs above the food waste rather than directly on the food waste.
  4. mature larvae collection container - This container can be a simple as a bucket, but should have a lid to keep the larvae from drowning in the rain. It should also be "breathable" and "opaque" because the larvae are sensitive to light.

My goal is to create a low cost DIY bsfl compost bin that can be made in a few hours with materials that can be sourced from any hardware store. I have started with the harvesting system for the bsfl bin. The diagram at the top of the page shows the homemade black soldier fly harvesting system consisting of a Rubbermaid® Roughneck™ 18 gallon / 68.1 liter storage bin and PVC pipe. I used a 4'-0" section of 2" PVC and several PVC connectors. The migration ramps are created by cutting away half of the PVC with a jigsaw. This allows the bsfl to self harvest with the compost / food waste at various levels in the bin. As the volume of food waste / compost increases the bsfl are still able to use the migration ramps. I didn't use any glue on the PVC fittings so that everything can be adjusted as needed. This allows me to modify the angle of the ramps to reduce the chance of adolescent larvae prematurely crawling out of the system. For maximum crawl off efficiency the ramps need to be against the side of the bsfl bin. The migration ramps are redirected via 2 PVC 90 degree elbows to a central PVC "TEE" fitting. This "TEE" is where the two migration ramps converge dropping the larvae into the final leg of the system. The last 90 degree elbow allows for a straight PVC run to the exterior of the compost bin where the black soldier fly larvae can be collected with a bucket. I have been testing this system in the garage so I have just let the larvae fall into an open bucket. The initial tests have been very successful. I look forward to exploring the other parts of the system and ending up with a bsfl harvesting bin that can be self sustaining in the yard. Stay tuned for the drainage system, the egg laying zone, and collection container. If you have any design suggestions, please leave a comment on the blog or email me at resplore [at]

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