As I wander the web in search of black soldier fly information I occasionally find well meaning folks with blogs or on forums making inaccurate statements about BSF. This is the beauty and the danger of the internet. In most cases I will contact those who made the incorrect statements and try to explain my position to them. Sometimes I find these websites because they have linked to this blog. Hopefully in those cases people will come here and get opinions from someone with more experience raising black soldier flies.
The #1 most frequently made false statement about BSF :
Odor; most of the incorrect statements I find relate to foul odors which are wrongly reported as part and parcel of working with black soldier fly larvae. I’ve said it a hundred times and I will say it again. A BALANCED BSF COLONY DOES NOT HAVE A BAD ODOR. AT ALL. Wow, I can’t believe I used the caplock button. It gets frustrating when people make the assumption that because their experience with BSF included bad odors that it’s an unavoidable condition. In fact, it is easy to avoid foul odors and at the first sign of bad odors a person can find the cause and fairly easily correct it. As I’ve said repeatedly; a balanced BSF colony smells like wet straw and whatever you’re processing. If you’re adding strawberries to your unit then it should smell like wet straw and strawberries. If you’re adding cinnamon bread it should smell like a bakery, not an outhouse. I have experienced this effect for years. I am not lying.
Bad odors would be the result of anaerobic bacteria which cannot thrive in a properly maintained BSF composting unit. BSF are not attracted to waste that is anaerobic and if not contained they will migrate away from such waste. Anaerobic (no air) bacteria will typically multiply in a BSF colony for two main reasons:
- The waste is too wet. Drainage is a key factor in maintaining a balanced colony because waste that is covered by liquid supports anaerobic bacteria. The long term solution is to redesign your unit so that it drains properly. At this time the best solution seems to be using some type of filter material like coconut fiber (coir) to avoid clogging of the drain. One issue with using coir is that the larvae will crawl through it, causing it to expand and lose efficiency. Various solutions suggested to deal with that include weighing the coir down with rocks, soil, etc, or using a wire mesh to do so. A short term solution to excess liquid is to soak it up with dry food items like stale cereal, or to add sawdust (non-pressure treated). I have had good luck using sawdust.
- There is too much waste for the number of larvae, in other words, overfeeding. BSF consume waste so quickly that bacteria don’t get much of an opportunity to grow. BSF compete with bacteria and given a colony with the proper density they will succeed. So, if you’re encountering bad odors in your BSF colony the first thing you should consider is cutting back on the quantity of waste you’re adding and in the short term you should probably completely stop adding waste. On average the larvae should be consuming the waste within two days. Hard items like potatoes will take longer to process and soft items like fruits, cooked grains, dairy products, etc, should disappear in hours or even minutes.
It is the churning action of the black soldier fly larvae that carries oxygen throughout the waste, thus keeping it from becoming anaerobic (smelly). Excess liquid and overfeeding reduce this effect to the degree it is happening. I have used BSF to process fish that I’ve culled from my pond during hot south Georgia summers. Last year I added over 50 lbs (22kg) and at anytime you could stand next to my BSF unit and not know there were fish being processed. I could open the lid and still not smell bad odors. Of course I would only add a few pounds at a time and those fish would disappear within one day except for some bones which apparently don’t smell bad. I’m really not making this stuff up folks.The photos below show my BSF consuming fish over a four hour period. There-was-no-bad-odor-at-any-time.
The blogroll:
I hope that those listed below will not take offense, most of the people making these statements are involved in sustainable practices that I support. Still, I feel it’s important for me to do my part to reduce misinformation concerning BSF. If anyone listed below wishes to defend their position they may do so via the comments for this page.
Wormbincomposting.com
“Black Soldier Fly Larvae (bsfl) or phoenix worms often occupy outdoor bins during the warm months. I call them maggots – they are nasty in my humble opinion. phoenix worms, black soldier fly larvae, bsfl They pose no threat to your worm bin- in fact they eat faster than your worms, so if you have some, watch your feed, you may need to feed more often. There castings or poo can become worm feed. BUT and it is a BIG BUT, the castings of BSFL smells putrid, I mean it makes me gag and I used to be an ER nurse and nothing makes me gag. It was not the smell of an anerobic bin, it was a very distinctive smell, something others that I know who have BSFL bins have experienced as well. This was my experience with them and for that reason I will not ever have a bin dedicated to just BSFL. Of course, I prefer worms. AND, if you are planning on selling the castings, people dont want maggot looking creatures in their purchase. So I hand pick them out or lately, I set a chicken on the bin and let them peck them out. Chickens and fish LOVE BSFL. If you do nothing at all, they usually go away on their own. ” – March 20, 2010 – http://www.wormbincomposting.com/wormcompostingbugs.html
I sent a message to Liz of wormbincomposting.com explaining that BSF composting does not involve bad odors when the colony is in balance. She responded by saying that if she changed her comments it would be the equivalent of telling a lie. I don’t see it that way but she’s entitled to her opinion. Liz, if you’re ever in SW Georgia in the summertime, please feel free to visit my place and I will show you what a BSF colony smells like when it’s managed properly. Just let me know if you like cinnamon better or cantaloupe. 
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