"And the Lord God took the man, and put him into the garden of Eden to dress and keep it". Genesis 2:15

Tuesday, May 14, 2013

My New and Improved Black Soldier Fly Set Up

I have had a Black Soldier Fly contain for about 3 years now. I found the Black Soldier Fly Larvae by accident, and raise them for fun and to sell to a few friends who feed them to their chickens. Well something about my set up, about everybody's set up, has always bothered me - it's the ramps the BSF use to self harvest. These ramps are such a pain to set up and hard for the BSF to find and use.

You can look at my old set up here. It's a 55 gallon water drum with a door cut in the side. I used PVC pipes for ramps that ended in collection buckets. Although the system worked, I always felt the chances of the BFS larvae finding the ramp and using it were not as good as they could be. A broad ramp leading to a broad exit hole would be better, but you can't just insert a plywood ramp into your set up. First of all it will rot, and second of all, BSF can get through any crack and they will all end up lost on the other side of the ramp. Then I thought one day, why bother with a separate ramp? Why not tilt the whole container the 20 degrees I wanted and cut a long slit for an exit hole in the side?

Here is the design my husband and I came up with. The design was mine and the execution was his (of course.) The barrel is tilted at a 20 degree angle. The collection bucket is the beige container with the green top on the right. The drain goes to the jar with the red top on the left.

There is a slit cut inside at the high end of the barrel. The larvae will instinctively crawl up and fall out of the slit, into the collection bucket, when they are ready to pupate. The barrel was pretty full since I hadn't cleaned it out in a few years and it was very mucky since my old drain did not work too well. I have a lot of composting material to spread around now.

There is a wooden stop at the low end to keep the barrel from sliding off the support. My husband thought of this and this stop was really needed. You see I wanted to simply prop the barrel at an angle with cinder blocks and, no, that did not work, so don't try it. The barrel gets pretty heavy and just slides right off of cinder blocks. My husband stepped in at that point and built me the wooden frame. He's so handy!

There is a drain here as well. I pour the liquid in my compost tea maker.

At the other end we have a support for the collection bucket. We ended up making the slanted support for the bucket, because we could not figure out how to cut the bucket properly so that it would fit up against the barrel right. The geometry of a cube partially intersecting a cylinder at an angle was beyond us! So the collection bucket is tilted at the same angle as the cylinder, which makes it much easier to cut the sides so the bucket snugs up against the barrel. The wooden slice of a circle you see in the picture was what we used to draw the cutting line for the supports and the side of the collection bucket.


The lid of the collection bucket had to be cut too. We just measured from the exit slit to the end of the barrel, then fit it by trial, and no error thankfully.

Some of the larvae after a few days.

 The system works great! I am getting a lot more larvae each day with this simple integrated ramp (doesn't that sound fancy.) I can't believe I didn't think of this before! Send me your comments and questions!


  1. Hi. I am looking into harvesting BSFs for my chickens and this looks great! How do the flies get in the bucket to lay eggs? Are there holes in the top that I can't see? The integrated ramp us brilliant.

  2. There are no holes in the top, but if you look at the door, you can see that it does not fit snugly. I have watched the Black Soldier Flies buzzing around and they don't seem to have any problem finding the way in. There are some holes in the ends of the barrels also for ventilation, but I plugged up the ones on the low end, and left the ones on the high end.

  3. Thanks for posting this... I think this is going to be the basis of the design for one I make. I'm wondering though... is the usable volume of the barrel diminished by having it at an angle? can you pack scraps into the barrel above the level of the slit or not? I'm working on plans for 50 broiler chickens (and 10 turkeys?) here in a few weeks, and I'd like to raise enough BSF to be a major protein source, so I would need significantly higher yields than what you have pictured.

  4. You can pile the stuff up in the end without the slit just fine. Stuff does not really last very long in there anyway as the BSF eat it all up pretty fast when you have a lot of them.

  5. Thanks Florence! I got mine up and "running." I put it out by the garden, propped on rocks, but am thinking I need to move it under the car port and make a stand after all because my collection bucket gets water in it and I think they've been crawling right up the sides and out of it bc. of the moisture. The one modification I made that I think was good was to use a plastic drawer unit for my collection bucket and screw it right onto the barrel. It doesn't need a stand that way, and is easy to empty.

  6. RJG, Maybe you could post a picture of your setup?

    I moved mine onto a side porch a while ago because of ants - for some reason they cant find it there - and it keeps it out of the rain.

    When it rains and the humidity is super high, they can crawl right out. I dont mind too much as I want some escapism to produce the adults.