To get about 1 kg of black soldier fly larvae, the food input can be around 3-5 kg daily. The amount varies depending on how many larvae are in one place, what type of food is available for the season, or more practically the cost of the food at the moment.

If you start from 50 grams of BSF eggs & growing conditions are good, you could end up with about 200 kg of larvae after 15 days of raising.

A grower asks then: how many black soldier fly larvae will make up 1kg weight?

Good question. It depends on when you harvest the larvae. For example, for 15-day-old larvae, about 8000 larvae will make up 1kg. For 5-day-old larvae, over 833000 larvae will equate a kilo.

Larvae stage Larvae count in one kilo Average Individual larvae weight
5 days old 833000+ larvae 0.0012 gram
10 days old ~16000 larvae 0.0625 gram
15 days old ~8000 larvae 0.125 gram

What this means, as a quick way to get 1000 15-day-old larvae for sale, you could measure 125 grams of them.

But enough of the weight measurements.

Going back to our topic of feeding:

In some places soybean waste, or the left-over of tofu making, is very cheap. So growers can feed the larvae a bit more with this stuff.

As an estimation, for 1 kg of larvae, the feeding amount can be:

Daily feed amount for 1 kg of larvae
4-6 kg soybean pulp
3 kg spent potatoes
5 kg beer grains
2 kg rice bran
1.25 kg chicken broiler feed
okara-soybean-pulp
Okara or soybean pulp / waste | Source

The larvae themselves can consume 5-10 times their weight. This means they can eat 5-10 kg of food easily if you let them to. But this may not be something practical to do due to the costs. So people adjust the ratio to about 1:1, 1:2 or some ratio that fits their needs.

The average feed cost range in different places goes from $0.03 to $0.20 per kilo. Some places utilize the food waste sources that they can get for free or very cheap.

If you grow these foods in your garden or have chickens or ducks, you can get some of the veggies & manure to feed the larvae. End-of-season fruits or foods that are available in abundance are great sources to get started.


Some Notes on Feeding

#1. Temperature

If you use rice bran, it's good to mix in some beer grains, spent cassava or spent barley. Because rice bran alone generates quite a bit of heat. Together with the body heat of the wiggling larvae, this can make the feeding area hot & uncomfortable for them.

The very max they can go is 105-110F (40-43C). Sometimes you can even feel it when you put your hands near the feeding area. If the density is low, the larvae will find cooler places to move out. If the density is high, then this can make the larvae grow smaller & slower.

If it gets cold at night in your local area, place some burlap or a piece of fabric over to keep the larvae warm. The lowest temp to keep them active is about 65-70F (18-21). Below that the larvae may go into hibernation.

Covering the feed area also lowers the chances of houseflies laying eggs in the same area. The warmth helps keep your larvae growing steadily at a good size.

#2. Density

If you'd like your larvae to grow bigger, then consider spacing out the population. For example, for 1 meter square put in about 3-5 grams of egg initially. With this amount, in 2 weeks, you can end up with about 15-25 kg larvae.

The total food input is 25-45 kg depending on your food choice. The larvae tend to grow bigger in a less crowded area which doesn't cause the heat issue & they don't have to fight for food too aggressively.

#3. Pre-Treating Foods & Reducing Foul Smell

If you get food sources from some other places & don't know whether the foods contain pesticide residue, it's advisable to spray them with some beneficial microbial enzymes. Some good microbes are the Lactobacillus, Bacillus, Saccharomyces. These guys help break down any potential trouble makers & keep the food almost smell-free. With a less unpleasant smell, it's easier to handle for humans & also discourages houseflies from getting near.

They usually sell the enzyme in a bag. For 1 kg enzyme, mix in about 3-5 kg sugar (or molasses) & 100 liter of water. From this starter enzyme, we can then add 900 liters of water to make 1000 liter second-generation enzyme that can be used to chop down any left-over pesticide residue or harmful stuff. This process happens quickly within about a week. You can also try fermenting or 'cool boiling' the foods for 4-5 days to keep it safe & reduce the smell.

For fermenting food for black soldier flies, you could check out this post later:

#4. Shredding, Turning, Moisture & Air Flow

Shredding or cooking the foods is not totally needed but it does help the larvae to digest easier & faster. It's okay to turn the food every now & then. This helps dissipate the heat out so it doesn't get too hot in one place. It gives some more oxygen to the babies & helps distribute the food pieces more evenly for everyone.

A good moisture content for the foods is around 60-70%. If it gets too wet, there may be less oxygen for the larvae to breathe. It might also attract grain mites if you're using grains. To fluff the food up if it's overly moist or mucky, use some dry sawdust or coco peat to absorb some of the moisture out.

For good air flow, some people use rice husks or spent barley. This makes it easier to sift out later when you harvest your larvae.

In Summary: The Input & The Output

The food intake & larvae yield can be estimated to something like this:

Grams of egg Daily food Total food 15 days Larvae yield
10 3-4kg / 6.6-8.8lbs 50kg / 110 lbs 20kg / 44 lbs
20 4-6kg / 8.8-13lbs 60-90kg / 132-198 lbs 40kg / 88 lbs

The key is the cost of food input, which varies depending on the season. Once we get that solved, the returns from the larvae for the fish, chickens, pets are quite impressive & sustainable.

If you have any comments, please leave them in the comment box. Thanks for visiting & Good luck getting started!

Responses to Readers' Questions

Can we feed cattle dung to larvae

--> Thanks for your question. From some growers' experience, cattle dung may not give the larvae much good nutritionally. As cattle eat grass, their poop is high in fiber (cellulose), a stuff which the larvae don't seem to digest well. This could relate to some micro-organisms available in the larvae guts. Similar with tree twigs, wood or coco fiber, the larvae don't like eating them much. In one grower's little experiment, he fed the larvae with cow dung vs soybean waste. They seemed to grow smaller/slower on cow dung.

Off the BSF topic, but with the available cattle waste you could feed them to red worms. They like it.

I hope this helps!

[Via our contact form] a question about BSF Hi, I like to know how many kilogram food is enough for 100g youg larva for a 2 weeks harvesting? I decide to feed them only one time (instead of feeding day by day), tell me how can I count the quantity of food? Thanks a lot

Hi,

As a rule of thumb:

10000 5-day-old larvae (about 12 grams) in one 60 x 40 x 17 cm container, feeding on 15kg of wet waste (75% water) for 12 days.

It is recommended to feed them three times: day one, day five and day eight. So the food does not pile up too thick at once. 5cm or less of food thickness is good.

Or in another way:

40000 5-day-old larvae (about 48 grams) in 1 meter square, are fed 60kg of biowaste for 12 days.

Notes:
- Each 5-day-old larvae is about 0.0012 grams on average
- Why 12 days? Because 12-day-old larvae (not yet transformed into prepupae) reach maximum weight and pack maximum nutritional value in them. With good feeding, they can be harvested at this point.

(Update 24 Jun 2022): Additionally, to add some more info for you about the 12-day-old larvae, it is related to the chitin amount in the larvae. Chitin, when consumed by monogastric animals such as rabbits or chickens, could prevent digestive and absorption process of nutrients. E.g. causing protein binding in the animal guts. This is why people feed the larvae to the animals when they are still whitish and have not turned too dark. 12-day is a good point. This is because chitin becomes more prominent towards the end of the larval stage (ie. when the larvae have turned more dark). Feeding them when they are still cream larvae provides good proteins and fats for the livestock while preventing the chitin build-up problem. Thought you might find this useful.

Thanks to a bsf group member for sharing such valuable experience.

I hope you stay safe and sound.

Best,

ZG

In my place bsf containers ar enot available , suggest in in which i should grow my bsf larvae and how to harvest them for my fish farm. Can i place the eggs directly in the container{which u r suggesting} or should i place eggs seperately and place 5 days old larvae in the container { which u will suggest}

--> Hello, thanks for your question. Firstly, in face of challenge, pls be innovative. I have seen many growers use plastic containers to grow their larvae. In some places, people build cemented brick rectangles or containers as feeding places for the larvae. Remember it doesn't always have to be the exact sizes. This is only one way of doing it. There are farmers doing it with their own ways with good results. You will need to look around your place for the suitable materials and make adjustments of the feed amount accordingly as you gain your own experience. But I can give you the rough numbers for a start: for a 3 square meter feeding unit (measuring 1 meter by 3 meters), people put about 1.3kg of 7-day-old larvae with 50kg of soybean waste. It will be enough for 3-4 days. Take note that BSF larvae can eat 4-10 times their body weight a day.

how to harvest them for my fish farm: You can harvest the larvae live on 12th day and feed them live to your fish. Before turning completely darkened, this is the time when the larvae pack the most amount of nutrients in them. You can separate the residue using a manual or electric sifter or using water. If you're processing the BSF larvae for pelleted fish food, a good recipe can be:

  • 35% BSF larvae
  • 40% Cornmeal/soybean meal
  • 25% Greens/carrots/cabbage

You can consider making the pellet in round shape for the fish for easy swallowing and digesting.

Finally, your last question: No where have I suggested placing eggs directly in the containers. I believe you may also find your answer here: https://zenyrgarden.com/how-to-keep-black-soldier-fly-larvae-population-uniform/

Be patient, BSF will reward your farm accordingly. I hope this helps!

To feed my Larvae to Chickens. Do you have a good recipe for best results?

--> Thanks for your question. People usually recommend 1/3 ratio each of green, grain, and larvae for the chickens. I have the detailed recipes for little and big chicks here in this post if you would like a look:

'How to feed chickens with black soldier fly larvae' https://zenyrgarden.com/how-to-feed-chickens-with-black-soldier-fly-larvae/

I hope this helps!

How many square feet do I need to get 1kg of black soldiers fly?

--> Thanks for your question. I have written about this somewhere in the posts. Have tried searching but not found the answer for you yet. I'll get back tmr, wait for me.

Hello again. If you start 5 grams (0.17 oz) of bsf egg in a 1 meter square (10 square ft) space, in about 2 weeks you could end up with 20 kilos (44 lbs) of larvae. In other words, if you build a bin/box around 12-15 square ft for the larvae, then on average you can get a yield of 2-3 lbs (~1 kg) of larvae a day. This can be used for fish food/pet food or whatever you see fit. Keep us posted & I hope this helps!

black soldiers fly leaves How much must be dried to get a kilo? I have already started on your advice. Thank you very much

--> Hi there, thanks for your question. From what a grower shares with me, it usually takes about 3 kilos of fresh larvae to get a kilo of dried larvae. I wish you success on your bsf raising. Hope this helps & See you again next time.

Do the larvae grow well on fruit waste of one kind? Eg. Mango peels alone Or mango pulp alone For the whole growing period?

--> Hello, thanks for your question again. Larvae could grow on food/fruit waste of one kind but according to growers who have shared their experience, it may not be enough for them speaking nutritionally. The larvae do require a certain nutritional profile for faster growth. Some farmers mix different organic waste (fruits, vegetables, starch for energy) for a proper balanced diet. I hope this helps!

How many kg can be obtained by drying 1 kg larvae

--> Hi thanks for your question. From farmers' experience, it usually takes 3 kg of fresh larvae to produce 1 kg dried larvae. So if you dry 1 kg fresh larvae, the kg obtained could be 1/3 kg (~about 333 gram) dry larvae. I hope this helps & See you again next time!

how much waste is required to attain 100kg of BSF larvae

--> Hi, really good question. BSF larvae can eat 5-10 times their body weight a day. So if you're raising it to process bio-waste (the waste source comes free of charge), it can be up to, I'd guess and estimate, 1 ton to 1.2 ton of waste over a 12 day feeding period to attain 100kg of larvae.

However, as most are raising to get the larvae as feed for pets or livestock, waste costs can be a consideration so the ratio can be reduced starting from 1:1 or 1:2. This means, 1 kg larvae : 1 kg feed or 1 kg larvae : 2 kg feed. So applying this ratio from about 150kg waste or 225-250kg waste for 100kg larvae.

Hmm I think the difference between these two may be the size of each larvae (fat or small). So with a 1:10 feed (1 kg larvae : 10 kg feed) possibly each larvae will be fatter and weigh more (so there is fewer larvae in a 100kg). Similarly, in contrast, with a 1:1 (1 kg larvae : 1 kg feed) or 1:2 feed ratio, each larvae might be smaller or thinner so there is more larvae to make up 100 kg.

I'm not sure if this confuses or clarifies it for you. Will check the numbers again. But I think the numbers may vary depending on growing conditions and feed. I mean, let me search/ask around also. When time allows, I'll get back to you. Anyway thanks & I hope this helps!

Hey again. My fellow friend / bsf farmer (Martin Tenywa at Ento Organic Farm: https://www.youtube.com/channel/UCRgr7H0o3y6AkR6lmkZXwYg) has helped me again with the answer. I'm so happy and grateful. So from his experience, it's about 100kgs waste for getting 30kgs fresh larvae. The waste composition is 80% fruits and veggies + 20% dry material of any bran. The feed period is about 8-10 days in a 3ft by 8ft (about 1 meter by 2.5 meters) feeding area or box. And it usually starts from 25-30 grams eggs depending on the hatch rates. So for 100kg larvae you could prepare about over 300kg waste and possibly separate them into 3 boxes for good growing. Again, I hope this helps!

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