In this article, we look at how black soldier fly larvae are the perfect way to compost waste materials.
Be it as a feed supplement or for breaking down yard waste, black soldier flies have earned a name among traditional composting circles.
They help create compost with high nutrition levels, resulting in better plant growth.
With optimum moisture levels, you, too, can convert your agricultural wastes, household food waste, animal waste, and other kitchen scraps into a compost pile.
Let’s dig into how these flies can help turn your kitchen waste into something better.
What Are Black Soldier Flies?
Black soldier flies, or Hermetia illucens, are a type of commonly found fly belonging to the Stratiomyidae family.
They closely mimic the organ pipe mud dauber wasp, even having a thinner abdomen, giving them the famous “wasp waist.”
Since the 20th century, soldier fly larvae have become increasingly popular as compost-friendly insects that help break down matter.
They are even shipped in the larval stage to various agricultural farms that want to produce compost.
The main difference perceivable to the naked eye between a common housefly or blowfly larvae and black soldier fly larvae is that the latter has a gray-black stripe on its rear.
What Nutritional Benefit Do They Add To Compost?
Black soldier fly larvae are great sources of protein. Their bodies contain around 50% crude protein and 35% lipids.
Along with this, they are a good source of amino acids.
BSFL (black soldier fly larvae) bodies contain some beneficial amino acids, such as lysine and threonine.
These cannot be obtained from plants, making them a good addition to animal and chicken feed.
They are also consumed by humans in some parts of the world. As long as the flies are blanched, they’re safe to consume.
Many insect factories run by biotechnology companies produce black soldier fly larvae, which are then shipped to various farms.
When compost made with BSFL frass was used, it resulted in better vegetable yields.
The BSF frass fertilizer also had more nitrogen, calcium, phosphorus, and potassium than homemade compost without BSFL.
However, the benefits of BSFL also come from what the larvae feed on. The best larvae are those that feed on organic matter that has rich, digestible nutrition.
Larvae exposed to toxic chemicals, heavy metals, and pesticides carry them forward and can introduce the substances into compost and animal feed if added.
How is Black Soldier Fly Composting Different From Normal Composting?
There are minor stage differences between composting with BSFL and normal composting:
Firstly, BSFL are more adept at quickly digesting different types of organic materials that take time with traditional composting methods.
You should monitor the amount broken down in a day and add the same quantity, decreasing it toward the end as the larvae grow older.
Soldier fly larvae need a varied diet. Usually, traditional composts are made with equal parts nitrogen and carbon, classified as brown and green organic matter, respectively.
BSFL, on the other hand, requires more animal products and processed products.
This makes it ideal for home composts, as cereals, coffee grounds, and waste meat can all be added to the pile.
How To Compost With Black Soldier Flies?
Composting with BSFL essentially means adding them to the substrate so that they can help with the composting process. After this, you can harvest the larvae and add them to poultry feed.
It’s important to note that it’s the larvae that help with composting and breaking down organic matter. Adult flies do not feed.
Hence, you should harvest the larvae while they’re in the pupal stage – at the latest—or you’ll end up with a lot of pesky flies!
Here are the steps to creating compost with black soldier fly larvae:
- First, you need to rear the larvae. You can do this in a specific rearing bin that has some substrate or directly add them to the compost. The substrate can be slightly damp coconut coir, straw, shavings, and coffee grounds.
- Offer the larvae different types of food items. Variety helps with quicker development. Ideally, 10,000 larvae feed on around 4 pounds of food items a day. This can be rice, vegetables, or fruits. Ensure that the earlier added food is broken down before adding more.
- During this stage, you need to keep your bin within a relative humidity of 50-70%. It’s best to use a sealed bin with a monitor. A good humidity range is essential for the larvae to get to work.
Once done, sift the larvae out. You can now use the composted matter as soil manure or livestock feed.
To turn the larvae into feed, blanch and dry them, and finally pulverize them.
Alternatively, you can keep the larvae in the bin and repeat the composting cycle, or simply place them elsewhere in your garden.
Larvae do not feed on live plants. As flies, they might return to the compost pile to lay eggs again.
It’s always advisable to test BSF compost before adding it to plants. Sometimes, it might contain digestive toxins or high levels of salt, which can negatively affect your plants.
Wrap Up
Black soldier flies aren’t pests. Since adults don’t feed (or bite), chances of them transferring any bacteria onto a human are rare.
If you do find them around, try investing in a small compost pile. These insects have high and efficient food conversion rates.
The final frass produced is odorless, making it ideal for smaller homes.
If you do smell the odor, it means the earlier food given has not yet been converted and has instead decomposed by itself, prompting bacterial growth.
Thank you for reading.
Frequently Asked Questions
How does black soldier fly compost work?
Composting with black soldier fly larvae (BSFL) involves adding them to the substrate to aid in the composting process.
Only the larvae help with composting, not the adult flies. Harvest the larvae while in the pupal stage to avoid an infestation of flies.
Rear the larvae in a specific bin with the substrate or add them directly to the compost. Offer them a variety of food items and maintain a humidity range of 50-70%.
Sift out the larvae and use the composted matter as soil manure or livestock feed. To turn the larvae into feed, blanch, dry, and pulverize them.
Test the BSF compost before adding it to plants to avoid potential negative effects.
How do you get rid of black soldier fly larvae in compost?
To prevent or control fly larvae in your compost bucket, empty it weekly, freeze or refrigerate food scraps, snap the lid on and limit openings, avoid leaving food out, and spray them with vinegar.
Keeping the bucket outside can also limit exposure to larvae. BSF eggs take 4 days to hatch, so weekly emptying is important.
Boiling water can kill larvae, but vinegar can also be effective. Testing with different types of vinegar is ongoing.
What are black soldier flies good for?
Black soldier flies are a good source of energy and clean food as they eat a lot and their digestive processes kill bacteria.
They reproduce at a higher rate than cows and are easy to farm and harvest. They are efficient at converting feed into food and have a short life span of only 6 weeks.
Do black soldier flies eat manure?
Black soldier flies (BSF) have been known for over 100 years and were initially considered pests that should be exterminated due to their presence in smelly farms and latrines.
However, early scientific papers discovered that BSF eats manure and has economic value.
12 Comments. Leave new
Thank you so much for your prompt and thorough reply. I will let them live in the composter, but you wouldn’t be opposed to a few being given to our chickens, would you…?
We are fine with that. We feed small earthworms to our Angelfish.
I live in Queensland, Australia, and have had “window-waisted flies” in my worm farm for a long time – I find that the larvae help to make compost much faster! The flies don’t even seem to need to leave the boxes – it seems that they complete their whole life cycle inside (in the dark) over and over…they also don’t seem to bother the worms much. I find it all fun to watch and lovely to have harmless creepy crawlies to show and teach the kids!
Thanks for the positive affirmation on Soldier Fly larvae in the compost pile.
Hi!
I’ve got the same larvae in my compost pile, here in Portugal.
In summer there are so many beneath a slice of bread, that I can catch a handful of them. It appears that the fly is worldwide.
Thanks for reporting on this.
Hi!
I’ve got the same larvae in my compost pile, here in Portugal.
In summer there are so many beneath a slice of bread, that I can catch a handful of them. It appears that the fly is worldwide.
Im here in Savannah, GA and I have a lot of theses larvae in my compost bin also.
We have discovered an exodus of these interesting larvae moving from our patio towards the dirt backyard over the last 24 hours. We’ve had a great deal of rain here in Tucson, AZ over the past two days and it appears to have brought them out in droves. We will toss them into the compost bin, and perhaps give a few to the neighbors’ chickens (who will be most appreciative!).
I have been seriously composting since a year and was discouraged by finding these worms in my bin, I didn’t wanted to quit so was trying my own ways, but finally by visiting Your site I’m so happy and relieved…Thanks a ton
I had a ton on my compost bin following a couple of rainy days. Thanks for the great info. I’m homesteading in NC by the way. We haven’t found any in the earthworm bins as of yet.
I’m new to vermicomposting and all was going great. A few rainy days and me not checking on the compost bin ended in what seems like a ton of the solider fly larvae. I started hand picking the worms out the bin n putting them into a larger vermicompost bin b4 I read this thread. I’m so relieved that it’s nothing harmful cause I’m raising cocoons in the bin and was afraid they would be in danger or get eaten. You just saved me a few days of picking thru the compost bin. Thank you very much for explaining exactly what they are and where they came from. Thank you!