Bsfl
Raising Black Soldier Fly Larvae at Home: The Complete Guide
Black soldier fly larvae (Hermetia illucens, BSFL) are one of the most useful organisms a small-scale homesteader, urban farmer, or reptile keeper can raise themselves. They consume kitchen scraps and food waste at extraordinary rates, convert it into protein-rich larvae, and are entirely non-pest — adult flies don't eat, don't land on food, and don't transmit disease the way houseflies do. A home BSFL bin can process hundreds of pounds of food waste per year while producing a continuous supply of feeders for chickens, fish, reptiles, and bait. The setup is simpler than people expect.
What you'll need
Equipment for a basic small-scale BSFL bin:
- A plastic bin (15–20 gallons) with a lid
- A drainage hole or inclined ramp for self-harvesting
- Some bedding material (coconut coir, shredded cardboard, or wood shavings)
- Starter larvae (50–100 to begin a colony)
- Food scraps to feed them
- Outdoor space — semi-shaded, protected from direct rain
Total cost: typically under $50 for the entire setup if you build the bin yourself. Commercial pre-built BSFL composters (Biopod, ProtaCulture, etc.) run $150–300 and offer self-harvesting features that simplify ongoing operation.
How the BSFL lifecycle works
The black soldier fly lifecycle takes about 38–45 days from egg to adult fly:
- Egg stage (3–4 days): female flies lay 500–900 eggs in cracks or crevices near food
- Larval stage (14–22 days): this is what you harvest. Larvae go through 5 instars, eating constantly
- Pre-pupal stage (5–7 days): larvae stop eating, turn dark brown to black, and migrate AWAY from food to find dry pupation sites — this is the self-harvesting trigger
- Pupal stage (10–14 days): motionless brown pupae
- Adult fly stage (5–8 days): flies emerge, mate, lay eggs, and die — they don't eat in the adult stage
For feeders, you harvest pre-pupae as they self-migrate out of the bin. Larvae stay in the food until they're full-grown.
The self-harvesting setup
The killer feature of BSFL composters is self-harvesting. Pre-pupae instinctively crawl up and OUT of food searching for dry pupation sites. If you give them an inclined ramp leading to a collection bucket, they harvest themselves with zero labor.
To build this:
- Cut or drill a hole in the upper sidewall of the bin
- Attach a length of PVC pipe or angled plastic tube (45° angle) leading to a sealed collection bucket
- Pre-pupae crawl up the ramp, fall into the bucket, and you collect them daily
Commercial BSFL composters have this designed in. DIY versions work just as well with basic plastic-cutting skills.
What to feed your BSFL
BSFL eat almost any organic material, but not all foods are equal:
- Excellent: fruit and vegetable scraps, coffee grounds, bread, grains, pasta, manure (chicken/cow/horse), failed brewing ingredients
- Good: meat scraps, eggshells, dairy in small amounts
- Avoid: anything with pesticides, citrus peels in bulk (acidic), onions and garlic in large quantities, oily cooked foods
- Avoid entirely: anything moldy or rotten beyond a day or two — fresh waste is fine, deeply rotten waste creates anaerobic conditions that harm larvae
Aim for about 1 lb of food per 1,000 larvae per day. A 5,000-larva bin processes 5 lb of waste daily — substantial for a household.
Temperature and conditions
BSFL thrive at 80–95°F (27–35°C). Below 70°F they slow dramatically; below 60°F they stop developing. In hot climates (Florida, Texas, Arizona), summer outdoor bins run too hot in direct sun — provide shade. In cold climates, BSFL only work seasonally outdoors; some keepers run year-round bins in heated garages or basements.
Humidity should stay around 60–70%. Too dry and the larvae dehydrate; too wet and the bin goes anaerobic. Add dry bedding (cardboard, wood shavings) if the bin gets soggy.
Starting your colony
Two paths:
- Buy starter larvae: 50–100 larvae from a feeder supplier gets you started. Place them in the bin with food and let nature take its course — adult flies will emerge, mate, and lay eggs to expand the colony.
- Wild-attract: in BSFL-native climates (most of the southern US, Mediterranean, sub-tropical), set out a bait bin with attractive food scraps and adult flies will find it within days. This is free but only works in warm climates with established BSFL populations.
Once established, a colony self-perpetuates as long as you keep feeding it.
Harvesting and feeding off
Daily routine for an established bin:
- Add fresh food scraps (1 lb per 1,000 larvae as a rough guide)
- Empty the harvest bucket — the pre-pupae that crawled out overnight
- Check moisture; add dry bedding if soggy
- Use harvested pre-pupae fresh, refrigerate for short-term storage (up to 2 weeks), or freeze for long-term storage
Pre-pupae are the most nutritionally dense stage and the standard form for animal feed. Live larvae work too if you prefer feeding active prey.
What to do with harvested BSFL
- Chickens: BSFL are roughly 40% protein and chickens devour them. Replace 30–50% of commercial feed with BSFL.
- Reptiles: excellent feeder for bearded dragons, leopard geckos, chickens, and most insectivores. See our BSFL collection for live and dried options if you'd rather buy than raise.
- Fish: tilapia, koi, and most freshwater fish take BSFL readily.
- Bait: pre-pupae make excellent fishing bait.
- Compost: if you have surplus, the residue (frass) is high-nitrogen compost.
Common problems
- Bin smells bad: typically wet conditions and anaerobic decomposition. Add dry bedding, reduce food input, ensure drainage.
- Larvae are escaping: pre-pupae are climbing the walls looking for dry pupation. Either harvest them or improve the ramp.
- No flies are appearing: cold temperatures, lack of breeding adults, or no protected pupation site. Adjust temperature and provide a dry corner with cardboard or wood for pupation.
- Houseflies are colonizing the bin: BSFL out-compete houseflies once established. If you have housefly issues, your BSFL colony isn't dense enough — add more larvae or wait.
Bottom line
A small home BSFL setup turns kitchen waste into chicken feed, fish food, or reptile feeders with minimal labor. Initial setup is under an hour, daily maintenance is under 5 minutes, and a steady-state colony processes hundreds of pounds of food waste per year. The biggest barrier is climate — BSFL need warm temperatures, so seasonal limitations apply in most of North America. For more on BSFL nutrition and uses, see our other guides in the Creature Insights blog.
Related guides
Last updated