One of our regular readers, “Vermiman”, wanted to share his DIY bin for harvesting black soldier fly larvae.
Here is his description:
The pvc pipes are angled at about 35 degrees to allow the mature larvae to leave the culture. At the end of the pipes there are elbows angled down into a collection bucket. There are holes in one side which allow the pipes to exit the bin. There are eighth inch holes near the top of the long sides that allow hanging of cardboard pieces where the BSF should lay her eggs in the little holes. On the other narrow side I made a square hole that allows the females in to lay her eggs.
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I’m a complete newbie here (just started my first bin a couple of weeks ago) and am wondering what the connection is between worms and BSFs. I can certainly see how the flies would find their way inside a worm bin, but I’m having a hard time imagining the benefit of harvesting the larvae.
Would you mind helping me make that leap? 🙂
hmm I was thinking what about a transparent sheeting ( aerated) sealing off a composting area? So as the larvae matures into flies they can mate outside…but within the plastic sealed compound… Just a raw suggestion anw
The benefits of BSF Larvae ? Woarhh Loads Dede, you can go fishing with it.. and its an excellent feed, with 40-45% protein, thats why.
DeDe – I can see how the topic of BSFL might seem a little strange given my site’s main theme, but believe it or not, raising soldier fly larvae in much the same way that red worms are raised is becoming an increasingly common practice. They are excellent composters, and as Izhizm has pointed out, they are also excellent as a live food organism. Unlike red worms however, they will actually harvest themselves if provided with the correct set-up (something along the lines of what Vermiman has shared with us above).
Izhizm – interesting idea. Thanks for sharing that.
I certainly hope you know what i meant LoL. Something like a tent perhaps? you have a sealed, controlled, environment… The same concept more or less how scientists handle mosquitoes..speaking of feed, the same concept probably have potential for bloodworm culture… hmmm
I think Vermiman’s idea is not only ingenius, it’s very cool!
I don’t know if BSF’s will ever replace Red Wigglers as the “Composters of choice” because of the Creepy Factor, but they certainly have become popular in the reptile trade as feeders.
Thanks for the reply Izhizm & Bentley. There’s so much to learn about this stuff! So, if I am understanding this correctly, the BSF larvae are good (we want them) because they also process the same compost and produce castings.
I’m still a little confused on the notion of harvesting. I think of harvesting as collecting something I want. With the worms, I know that their ever-increasing populations need to be managed so we must periodically “harvest” some of them to begin new beds or use in some other productive way.
With BSF, I can’t tell if we are talking about “collecting” the larvae (also for population control?) or getting rid of the adult flies. Would you mind clarifying this one for me?
Lastly, Bentley you mentioned the larvae are an excellent live food organism. Can you say more about what that is/does?
I’m sorry if this info has already been covered in a previous thread or if I’m bogging down the wheels of progress with my naive questions. 🙂
Bentley, Keep up the great work – I found this post to be interesting and of merit, just the way it is. I don’t think you need to spend alot of time quantifying the sharing of ideas. I appreciate the diversity of info.
I also enjoy the comments so far. I choose to do additional research and rediscovered Paul’s background and the efficiency of the BSF…
There’s a great thread about BSFs here:
I look forward to your next post.
DeDe – BSFL will literally harvest themselves once they reach a certain stage. The focus here is definitely more on larvae production than on ‘castings’ (if you can call them that) production. Other than laying eggs in the material, the adults are not part of the equation as far as I know. Generally these systems are kept outside.
BSFL are rich in protein and other nutrients – maybe someone else will chime in with more info than that. This really isn’t my area of expertise – I’ve been all about the worms thus far.
John – thanks for the kind words. Our ‘Paul’ here is indeed Dr. Olivier and he and I have actually continued our dialogue via email. He has been kind enough to share a great powerpoint presentation about BSFLs and I am going to convert it to a video format (and upload to YouTube) so I can post it on the blog.
I will repeat here what I’ve stated elsewhere:
I don’t think that my system is in anyway comparable to the biopod. I just think that if there is a “cheaper” way to get started then the popularity of BSFL may take off. And in turn bring up the sells of the biopod. I don’t think that many people would shell out $150+ for a composting system that they don’t know much about. Now that I have some experience with the BSFL, I look forward to purchasing the biopod this next Spring.
Sorry for my description of the harvester. I am very new to BSFL. The process of using FSFL for bio-conversion is quite new also.
The crawl-off efficiency of my system is in no way comparable to the closed system of the biopod. When the lid can be kept off, the walls remain dry and the crawl-off rate is quite low. But when the lid has to be placed on the unit, it produces lots of humidity and the walls become saturated,then the crawl-off rate becomes quite high. I place the lid on the unit when there is a chance of rain.
By crawl-off efficiency I mean the efficiency by which a mature larva ends up in a collection bucket. If larvae cannot make it out of the bin, and if larvae do not end up into a collection bucket, then this represents an inefficiency in crawl-off. The efficiency of crawl-off is the actual number of larvae that made it into a collection bucket divided by the theoretical number of larvae (prepupae) that reach maturity and begin migration in search of a pupation site.
I have seen bioconversion bin designs where the mature prepupae do not make it out of the bin and attempt to pupate within the bin. In many cases, they eventually die. Sometimes migrating larvae get stuck in corners. Sometimes they do not find their way to the evacuation ramps provided. Or if they do, the ramps are not properly sealed and do not lead in a rigorous way into a collection bucket.
With or without lids, atmospheric moisture can build up on the walls of the bin, and this gives larvae the possibility of crawling straight up a wall of a 90-degree angle. Therefore the top of the bin has to have several lateral and downward folds to prevent crawl-off in any other place than in the collection bucket. If liquids released by larval digestion do not drain properly, this also gives larvae traction they should not have. So the draining of liquids has an impact on the ease at which prepupae end up in a collection bucket. However if it becomes too dry within a bioconversion unit, prepupae will sense that the bin is a good place to pupate and they will not attempt to crawl out of the bin.
I am somewhat concerned about the do-it-yourself design posted on this website. The crawl-off efficiency of this unit will be quite low, for the simple reason that the larvae will have a very low probability of finding their way into the white plastic pipes provided as ramps. Instead of seeing a bioconversion rate of fresh food waste into fresh larvae of 20%, one might see a bioconversion rate of only 2% or 3%. This might give someone the impression that the larvae are not very efficient in converting food waste into proteins and fats.
If, for example, someone were to put in 10 lbs of food waste per day, one should expect to have on average about 2 lbs of larvae per day. Anything less represents in most cases an inefficiency in crawl-off. Also this 10 lbs of food waste will reduce to about a half pound of residue, which makes an ideal food for red worms. Redworms grow about 3 to 4 times faster on larval residue than on biologically degraded food waste.
How is this residue harvested in the biopod? Can citrus be fed to BSFL? It has been advised to keep citrus away from worms, due to the content of acid in the fruit. Will this acid cause damage to the BSFL?
I do understand your argument for crawl-off efficiency Paul. My unit sometimes has large harvest(1000s of grubs) but sometimes it has small harvest(less than a hundred).
I did not purposefully start a BSFL culture. I had a poop collection bucket under a rabbit cage that I used to feed to worms in a worm pit. One day when I was about to take that bucket and feed the worms, I looked in the bucket and saw the poop moving in waves. I took a trowel to moved the poop and saw that it was teeming with BSFL. I did a little research on BSFL and built my “newbe” DIY unit. I wanted to get to know a little about BSFL before going full fledge and purchasing a biopod. It would have been a waste of money if I was to purchased a biopod and then decided that I didn’t want to raise them.
The crawl-off efficiency of 20% must be and average. There are many variable that can effect that number. One would be variations in types of food scraps fed to the culture of BSFL. Another would be temperature. At cooler weather the larvae would be using more food to create heat and they would also mature more slowly. High temperature could cause early crawl-off. The immature grubs as long as they are large enough can be used in the same manner as the mature grubs. Overpopulation can also cause too much heat and early crawl-off. The immature(early crawl-off) grubs that I have harvested was comparable to the size of the mature grubs. There are probably other variables that I am not even familiar with and may remain unknown until I acquire a biopod.
Here’s some Q&A from a vermicomposting forum that may help a little.
What do you do with the larvae?
I use them for bait. If all goes well, next year I’ll purchase a few chickens and use the grubs to feed them.
What are the pieces of hanging cardboard(?) for?
The female black soldier fly(BSF) lays her eggs in the holes on the sides of the cardboard. The like to lay there clutch away but near the food source.
Are those airholes drilled along the edge the cardboard cutouts are hanging from?
The airholes serve a dual purpose. One, to allow air into the system when the lid is placed on top(when it rains). Two to assist in the hanging of the cardboard nest.
What is in the dish in the first photo?
That dish has small holes on the bottom edges. I bait it with food to harvest immature grubs when needed. This Idea originated from GW at the biopod forum.
What is the large cut-out to the right side of the bin in the third picture?
That is to allow the female BSF in the bin to lay her eggs. The hole was made too big and placed too low.
When you’re ready to harvest can you just stop adding food to the bin and wait for the larvae to mature?
If your talking about the compost, I don’t know. I’ve heard that it is a very good worm food. This is my very first time growing a culture of BSFL. So most of what I’m doing is by trial and error.
Looks like you cover your bin?, problems do you forsee with an open bin?
The bin is covered when it rains. When it’s covered the bin gets very humid and sides get very wet. That allows the mature larvae to climb the walls and escape through the holes. This lessons the harvest in the collection bucket. The bin seems to be best when used as an open system.
Very cool idea, thanks for posting pics!
Thank you, I thought that this may get more people interested in culturing the BSFL
Thanks for sharing that, Vermiman – that’s a great way to present more info about your system.
Thanks Paul and Vermiman for the additional info. I can attest to how well EFs work alongside BSFLs. I have consider separating my BSFLs into a separate unit in order to harvest a steady supply of protein for chickens or perhaps a aquaculture (with tilapia or similar fish) set-up.
I love the idea of creating a continuous loop. I love Dr. Paul’s idea of creating the bio-pods using hyper-tufa. I think these pods could be made so that there external shells are an attractive hardscape element while inside they are created for maximum crawl-off efficiency. This idea is presented in his powerpoint presentation on one of the sites I had visited a couple weeks back. I can’t find it now. : (
By the way, has this presentation been converted to a flash video and posted somewhere yet?
I finally uploaded a video version of Dr. Oliver’s presentation. It may seem a little quick in places, and hard to see, but unfortunately there is only so much you can do with YouTube.
Here is the new post:
Thanks again to Dr. Oliver for sharing this great info, and for everyone else who contributed to this thread. Definitely one of the more interesting comment threads thus far!
I’m very intrigued by the BSFL idea. I already have two worm bins, and they can’t seem to keep up with the household kitchen waste I generate. It would be great to have both systems working side by side. My question: If I have BSFL in my bin, will they reproduce by themselves within the bin, or will they mature and die off? Can both the worms and BSFL co-habitate in the same bin and reproduce effectively such that both populations grow?
Great info from your site!
BSF specialize in fresh food waste, whereas redworms specialize in partially composted food waste. The two have entirely different eating requirements. Therefore it is best not to attempt to cultivate them within the same bin. BSF larvae will not complete their life cycle in a worm bin, and there is no way that redworms could possibly survive in a BSF bin.
When you have a culture of BSFL with a large population they would create too much heat for worms to be comfortable much less thrive. Also a large population of BSFL generates a lot of fluid. Worms require a much more dryer habitat than the BSFL tolerate. My 2 cents: For the two species to survive and thrive they require two very different ecosystems.
Vermiman, you are correct. The redworms and BSF larvae require two very different environments to flourish optimally.
I like the DIY BSFL harvester that Veriman has created. I would have made the tubes much shorter, but that’s just me. Consider the Bio-Pod, a short distance from the food to the harvest entrance, plus, there is a collector for the compost tea ……. Veriman, incorporate that, and I, for one, would like to build one too …… Who cares about crawl-off rates, etc. the whole idea of actuallly making something that works has been accomplished, and you should be proud of your creation. Thanks !!
I think I am going to cobble one of these together. BAsed on the comments presented and after reviewing the biopod design, I am going to use a round keg type plastic tub as the BSFL residence. I will place the harvesting PVC pipes in a manner so that they rest up against the corner of the floor and walls on opposite sides, similar to the ramps of the BioPod. If the larva trudge around the perimeter, they are bound to run into one of the tubes. Plus, no corners to get lost in.
I will have the pipes angled up into the harvester bucket, but I will skip the downward sloping pipe and just let the boogers drop into the harvest bucket(s). I have some other thoughts, but I think it’s time to put it together… Meanwhile, I look forward to buying a BioPod once I get this operation off the ground. My chickens are going to love me!
I have started the BSFL bin this year again. The bin was loaded with house fly larvae at the early stages. House fly eggs hatch faster and mature faster than the BSFL. The fish in the local creek love to devour them tho. After the population of the BSFL explodes they tend to control the population of the house fly larvae. It is said that the smell of the BSFL is a signal for the house flies not to lay eggs there.
Any thoughts on the natural populations of BSF in Colorado or the West would be appreciated. I am going to replicate the home made system and as soon as I can afford to purchase a biopod, I will. I would really like to see Dr. Paul get a huge grant to send out both (are there 3 with the large ‘cement commercial’ size one?) designs to composting organizations across the country.
Really digging BSFL possibilities.
I heard about BSFL for the first time on a podcast today hosted by TheSurvivalPodcast.com. Since I have been entertaining the idea of raising rabbits, chickens, composting worms, meal worms, and possibly fish, I was fascinated with the idea of BSFL.
Just one question: Can someone explain more about the adult phase? I understand the mature flies have no purpose except to reproduce, so I’m wondering how do you go about seeding the biopod? I live in the Northeast US where they don’t live naturally. Do I build a tent around the top of the biopod and turn some of the pupae loose to reproduce in there?
On how to recycle food waste, manure and even human waste using soldier fly larvae and red worms: http://www.esrla.com/pdf/Brazil.pdf
On how to recycle residential waste: http://www.esrla.com/pdf/rsr.pdf
Where in the Northeast USA do you live?
To naturally seed a pod, put out some food waste in some shallow pans and wait 10 days. You must make sure the food waste does not dry out. Hang some cardboard strips above the food waste, where females will lay eggs.
Frasmus – As I understand it (and I’m no expert) the larvae as well as the adult fly both secrete various info chemicals or pheromones that attract the adults to breed and lay eggs nearby. Therefore completing a sort of loop. So you do not need a tent. I am in Colorado but I have not tried to raise/compost with these yet. I will post to this forum as soon as I get my ‘colony’ up and running. If you have not checked out the ESR or BioPod guys – they have great info too.
It sounds so simple, IF you live in the natural habitat for these little workers. I just love seeing those compost bins with all the “grubs” that come from nowhere. (On Youtube.)
I am in central New York state. I will have to investigate whether they will seed themselves naturally here. Seems I could create the right habitat for a reproducing colony though.
Simply check with all the people who do composting and vermi-composting in a particlar area, and you will quickly find out if BSF larvae are abundant in the wild.
I started a wormbin a few months back to deal with composting my kitchen scraps. They limped along until a few weeks ago, and as of now have all but disappeared. I think it’s due to the compost being too wet and too warm.
Anyways, as a result of that, I now have roughly 50 BSF grubs munching on my garbage. I’m more excited by these grubs than I was by the worms, partly because they’re free and also because they’re more hearty and seem to eat faster. My main concern, however, is getting *more*.
I’m still using my worm bin to compost. It’s a 10gallon blue rubbermaid bucket. Now that all the worms are gone, I drilled a few half inch holes in the side to allow BSF’s to get in there and lay eggs. Is there anything else I should be doing to ensure a maximum BSF population? I’m broke so no Biopod for me, and I’d like it to be low maintenance.
Also, how is the BSF waste as far as fertilizer? That was half of the original goal with the worms. Castings and Waste Elimination. Thanks!
If you want to promote a large population of BSF in your neighborhood, then it is important that the larvae on reaching maturity can get out of your bin, dig down into the soil and eventually emerge as adults.
Round holes are not the best way to accomplish. The best is to make fairly long vertical slots at least an eight of an inch in width. Of course you have to be careful not to compromise the strength of you bin. When the larvae reach maturity they will crawl along the sides of your bin (mostly at night) until they find a vertical slot. They will then crawl out without a problem.
The best of course is a round bin. A rectangular bin with corners is not good, since the larvae get stuck in corners.
The females will be able to enter the bin to lay eggs by means of the same vertical slots.
Thanks for the reply. What should I do with my existing system? Should I do something similar to Vermiman and hack something together with PVC? Also, I live in an apartment and there is very little dirt in the area. It would be better if I could keep it all as self contained as possible.
Cut vertical slots in a large round plastic bin, and you should be fine. Make sure that at any height, there is access to at least one vertical slot. The larvae will then find their way out.
if I have like 100 grubs in my bin, and they all reach the point where they’re going to hatch, but can’t get out of the compost bin…will they die, or will they hatch and turn into flies? I’m confused about this portion of the lifecycle.
The larvae must be able to pupate to complete the life cycle.
If it is dry enough in the bin, they might be able to complete pupation.
But if the pupae are flooded several times with fresh wet food waste, I doubt if they will survive.
I live in the Portland Oregon area. Do these flies live here and if not how can I sustain this system? Looks like something I would like to do. I raise reptiles and the grubs are a perfect food.
Yes, BSF are found in Portland.
If you want to harvest larvae efficiently, I suggest that you buy a biopod.
Thanks Paul. Is this something I should wait for the spring to start? How do I start the colony, add grubs to the biopad?
Man I wish we had BSF in Colorado!! Hey Dr. Oliver, I am going to Brazil for the month of November. Any interest in helping me set up a biopod near the Fortaleza area?
qualitytrent at gmail.com
I think that it is best to wait until spring when adult females will be around to lay eggs. When BSF females are present, you do not have to do anything.
They will lay eggs and assure a healthy population of grubs.
I can give you a lot of free advice. But you will need a biopod.
Thanks again. I will get a bipod, but I may wait until closer to spring to get it. Drop me an email rcivil at comcast dot net.
Dear All, It’s been great reading you. I discovered BSF just a week ago, when a friend was horrified by what she found in her compost heap. A little research later, and I’m in love! I’ve set up a container on my apartment building rooftop in Goa, India. The perfect climate – about a constant 30 degrees celcius year round (with great variations in humidity). There are adults BSF living locally (seemingly abundant) and already laying in my bin. My main use for BSF is waste management. I don’t as of today have a specific need for harvesting the pre-pupal larvae or compost (that will come once I’m out of the apartment and into a house). If the pre-pupae are unable to leave my bucket, I imagine some will manage to pupate in the drier edges of the bucket, but others will die. Will this create problems? I would eventually like a harvesting system so that the larvae can do what nature intended, but in the meantime, while I’m building my colony, is it necessary for the pre-pupae to be able to leave the bucket? Thanks kindly, in advance, to all. Rosie
The larvae turn black when they mature, and these mature prepupal larvae must find a way out of the waste, otherwise they will die.
If you see black larvae in your bin, try to take them out. Put them in some dry sawdust or rice hulls and a few weeks later they will mature.
Please see: http://www.esrla.com/pdf/ait.pdf
I’ve got to make my own bin, at least for the short term, as my wife has just about had it with the worms and bees.
How to increase crawl-off efficiency in a homemade bin?
How to keep ’em working over the winter (not just working, but reproducing)? I’ve read that even with supplemental heat the bugs somehow know it’s not breeding time.
I haven’t found much info on the web, I guess it’s a pretty new concept, and thus fun to be involved with.
– Mark in Santa Barbara
Do not try to make a homemade bin like the round bin that I am marketing.
Work with a square or rectangle, and have at least one side come out at a 45 degree angle. The larvae will crawl up this ramp when they reach maturity.
It is almost impossible to make a round bin in either plastic or metal.
But the rectangular bin is quite easy, but the efficiency of crawl-off is not ideal.
The round biopod that we make in Saigon is made by means of a roto-molding process. But the mold cost here is about $80,000.
I will sell BSF bioconversion units of 2- and 4-foot diameters to anyone willing to make an investment in at least a 20-foot container.
My US telephone number is: 1-337-447-4124
I sell a complete 2-foot unit with collection bucket for $50.00, and a complete 4-foot unit for $75.00. This is not expensive for a permanent, long-lasting, roto-molded product.
If you want to build a BSF unit for personal use, it is much easier to do so in a square or rectangular shape. At least one side of this rectangle has to come out at a 45 degree angle to form a crawl-off ramp. This does not violate my patent. I can make drawings available of this DIY unit.