Thursday, November 8, 2012

Funky Bugs: composting with Black Soldier Fly

Life as a bug in our garden must be pretty good. there would be no shortage of friends and parties to attend, and no nasty chemicals to make you feel unwell. Life would be darned good, in fact, so long as you were the kind of bug that was willing to pull your weight in the garden and do your bit!

Not so, however, for the slugs and snails whom we introduce frequently to our chookens, nor the uncouth stink beetles that N and G sucked off our citrus trees with the vacuum cleaner (simply the most enjoyable way to get rid of them), nor the white cabbage moth that we use for practicing our backhand,  but there are many bugs that we do appreciate in the patch. Worms, bees and lady beetles are always welcome in our garden, doing their bit to pollinate, cultivate and eradicate pests, but we have recently become acquainted with a new creepy crawly of the good kind, known as the Black soldier fly (BSF).

black soldier fly (pleased to meet you)
Black soldierfly have a rather short and desperate adult life, with the sole purpose of finding a mate, a pile of rotting compost, and a good pick up line before dropping dead. Somehow they seem to manage. But before this fatally frantic paced lifestyle as an adult fly, they leisurely spend their childhood and teens as ravenous compost devouring larve!

BSF larvae eat just about any kitchen scraps including meat and dairy, as well as the usual fruit and vegetable leftovers, and can be cultivated in much the same way as composting worms, to break down food waste.  A BSF composting unit can be easily built from materials found at your local hardware, and once a colony has been established they can consume food waste at an incredible rate (much faster than worms), but best of all, they make a fantastic feed for chickens and even fish. BSF larvae are high in both protein and calcium, which is perfect for chooks. they are non invasive and do not enter houses or spread disease like other flies.

Once we got acquainted to this new bug on the block, we realised it was time for us to try our hand at making our very own BSF Composting unit!

Our black soldierfly composter

TA DA!!!! Our Black Soldier fly composter

Here is how it works. Food scraps go inside and the female BSF are attracted by the scraps. They fly in through the pipe at the top and down into the bin where they lay their eggs (in the hundreds). They like to lay their eggs in crevasses, so some sheets of corrugated cardboard attached to the inside make great maternity wards. the eggs hatch and the larvae fall on the food scraps, and get to work munching it up.

the larvae crawl up the pipes and into Jo's Tupperware container... thanks darling...sorry
 Like all good teenagers they eat just about anything until it is time to finally leave home, at which point, the larvae develop the instinct to climb to higher ground. The larvae find their way to the pipes and climb up them, then slide down into the separate storage container, where they are unwittingly trapped to be fed to the chooks.

the larvae hard at work on one of our defiant choko's and watermelon rind
But does the composter work?

In a nut shell, yes. but getting started can call for some weeks of patience. Its best to start a colony in warmer weather when the adult fly is most active. Every few days we have been checking the tub, and after many weeks, we finally discovered some young soldierfly larvae munching away under the scraps. As the weeks progressed and the temperature rose, so too has our colony and the rate at which they are breaking down our food scraps is quite impressive.

Make your own
there are a number of DIY designs on the net. we made ours using a clip lock tub, some PVC pipe parts, , some hessian and fly screen, a saw and a drill. The key is to angle the pipes at 35 degrees so that it is not too steep for them to climb.include some ventilation holes and cover with fly screen, and some drainage holes in the bottom, which you can cover with hessian.  It takes less than half a leisurely hour to put together and cost us about $40 or you could buy one of the fancy ones online for about $200.

the main benefits are:
1. a very efficient method of waste disposal
2. meat and dairy waste can be added to established colonies, unlike regular composting methods, reducing your waste output.
3. the larvae make an excellent source of food for poultry and fish, and can be frozen for later use.
4. they don't spread disease like other flies, and rarely enter the home.
5. they emit a natural repellent to other flies once the colony has been established.

The smell can be an issue if you add more waste than they can consume. Sawdust or coffee can help here too. This said, ours does not smell.

Initially, we had a problem with fruit fly gate crashing the party. but as the weeks have gone on, there numbers have decreased dramatically as the BSF colony has increased. AHa, dear potential BSF composters, do not be dismayed by these minor downsides. we have an organic, effective and easy solution to manage fruit flies in the patch... read on!

Bug eyes and beer goggles - a simple and effective fruit fly trap

With the onset of day light saving and the Spring evenings becoming more balmy, there’s nothing quite like kicking back on the front porch with a home brewed beer or a chilled wine and watching the sunset. But it seems that we aren’t the only one’s who love a beer to celebrate the start of spring.
We have been using some of our beer in our fruit fly traps, and we have noticed that they are more than happy to exchange their bug eyes for beer goggles, which is great, seeing as our nectarine tree is laden with new fruit to be.

got ya succers!

The trap is simple. All you need is a plastic soda bottle, some scissors, and a beer on the balcony. Simply cut the bottle cross ways about a third of the way down from the top. Turn the top upside down and insert it into the lower part of the bottle, like a funnel. Pour an inch of beer (or wine) into the bottle, and if necessary, run some tape around the edge of the rim to keep the trap together. Place the traps around your fruit trees and compost bin, or any other place that fruit flies are being a nuisance. then drink the rest of your beer.
The fruit flies fly down the funnel and get stuck. "Oh save me! Save me! I've accidentally flown into a giant pool of beer. what ever shall I do???". After an initial panic attack, they come to their senses and drink themselves to death. What a way to go. It works surprisingly well, as fruit fly are naturally attracted to anything that is fermenting. We have tried a few variations, such as sour dough starter, orange juice, and vinegar, but beer seems to win hands down.

So if you're concerned about fruit fly this spring, relax, have a shandy, and make yourself a beer trap or two.

Our New chook pen

Talking about grubs and chooks, we decided recently that it was time to make a proper enclosure for our lovely ladies. Up until recently, their pen has been a makeshift tangle of old chicken wire and odd posts. It was a shabby-chic chook pen (but with more shabby and less chic), and so it was time for an upgrade.

We decided to build their enclosure around the fruit trees, to give them shade and also to fertilise the trees. The trees have since gone mad with a flush of blossoms, which have smelled divine this spring. the combination makes a lot of sense. The trees are robust enough to handle the chooks digging around, and the poop makes a much appreciated fertilizer for the trees. Meanwhile the hens can rest in the shade and help keep pests under control, such as fruit fly.

the whole enclosure cost under $250 (about $10 per square metre) . First we dug and cemented in the posts, making sure they were level...most of the time, then connected the cross beams. the wire was fastened into place, and last of all, added the gate.

Next blog, its time to go foraging, dabble in some heirloom guerrilla gardening, as well as try our hand at some simple home made wines from our foraging finds.


  1. gorgeous guys! we have heaps of sf on our farm ... and have been looking for an easy design.... thanks! how is the ever growing family doing????/ don't forget our door is always open if you get up the northern rivers way!

  2. hey maggie, how nice to hear from you! glad you might be able to use the design, easy as...we would love to drop in on you guys one day sooner rather than later, how are the tribe? how if the patch? the farm? etc? Crop & swap season 2 is underway, on again this saturday...keeps us busy ;)
    let us know how you go with the black soldier flies...they're incredible! x

  3. Hi Jo and Joe
    Lovely to meet you both today at the crop and swap. Here's the link to the yoghurt making post, I do it in a pot now though using a thermometer to check the temperature and then transfer to a warm slow cooker to set.

    We're looking forward to the mulberry jam!


  4. Landscaping Farmington CTNovember 20, 2012 at 8:19 AM

    Looks like a great enclosure. Does it keep out the critters though?

    Landscaping Frmington CT

    1. I wasnt ambitious enough to try and make it rodent proof, as they are a clever bunch of critters and would probably find some other way in anyhow. Its really just to keep the girls IN, so that they dont dig up everything that we plant, which they are excelent at.

  5. Great enclosure! Looks like an easy design but very effective!


    Landscaping Frmington CT

  6. This comment has been removed by a blog administrator.

  7. Wow amazing and love all you do here. Great great great. Love the new hen house, how great is

  8. Where are new posts? I like your blog that I just now found.

  9. I have not seen a single fruit fly since I set up a black soldier fly colony. they used to buzz around the compost but not any more. I think the BSF eat them too.

  10. So glad I found your blog. It is wonderful reading about things that others are trying. I love experimenting with new ideas,especially those related to my yard and gardening ventures. I love being outdoors, and I play all summer trying new things. I have tried raising red wigglers several times, but cannot get it right.Now I plan to try night crawlers,again. My soil is made up of a lot of clay. I have improved much of the areas I use over the last 35 years, but a gardener can never get enough rich black soil and composting is the key.I use my chickens to make my compost and that is one of the best ideas I have come up with.I catch all of the grass clippings and dump it in the chicken yard. They scratch and turn it daily looking for bugs.After it has decomposed and turned black, I go in with my leaf rake and my home made sifter and collect all the composted black soil I need.
    I have a blog and post often about my life's ventures,many of which are garden related.Drop by sometime.

  11. Are you two on sabbatical??? It's been 8 months and I want to hear all about assisting (!!!) your neighbours aqua garden!
    Liv x