Building your own DIY worm farm – known in fancy circles as vermicomposting – is a fantastic way to transform your organic household waste into a rich compost which both supports the local ecosystem, and nourishes your plants and vegetable gardens.
Not only does it provide a spectacular and sustainable nurtrient source for all your plants, it’s an exciting way to show kids (and kids at heart) how to recycle our organic waste and return it to the garden as compost goodness. Bonus points for being green!
The compost created from a worm farm is the compost equivalent of a 1991 grange – it’s deep, intense, nurtrient rich goodness. I am constantly amazed that our daily household scraps – with the help of these some little red wigglers – can make the most nutrient rich fertiliser for all plants and garden beds.
When building my own DIY worm farm (shown below), I found some helpful – as well as some not so helpful – DIY tips online to guide me. This resulted in a bit of trial and error (maybe alot of error), but I’ve managed to build a pretty sweet little set up that delivers me juicy compost on a regular basis.
In this article I’ll show you my step by step process for building a successful worm farm from materials you can grab at any local hardware store.
We’ll also touch on;
- Which worms to use for worm farms
- Worm bedding tips
- Worm bedding materials
- What to feed your worms (including what you can’t feed your worms!)
- How to add secondary levels to your worm farm and encourage worm migration
- How to deal with pests and unwanted guests (fruit flies, mites, ants, maggots)
- How to make your own worm tea or leachate
Lets get into it!
Thing’s you’ll need to build your DIY worm farm
- A Drill – with a spade drill piece to make a larger hole for the tap and smaller drilling bits for worm holes
- 3 plastic bins, containers or Styrofoam boxes and one lid (3 to start – you can add more later)
- A plastic screw tap
- 4 small terracotta pots (or bricks or anything that’ll hold the weight of your bins)
- 4 more pots or legs to hold the bins off the ground (old timber, whatever you have lying around – there are many things you can use for this)
- A gas lighter (or bbq lighter)
- Coco coir
- Hessian bag
- A little soil and some leaves from the garden
- Worms starter kit – 1000 worms (from your local hardware store or online)
Building your DIY worm bin
Using a spade drill piece, drill the the hole for your tap – in the bottom centre of one bin. Make sure your drill bit is the right diameter for your chosen tap. Screw in the tap piece. To tighten most taps come with a screw piece which you thread on the inside to hold it all in place.
This is now the bottom bin. If you are as fortunate as me your local hardware shop may screw it in for you when you purchase your items (cheers Bunnings!).
In your other two bins (not the bottom one in which you’ve placed your tap) you’ll next drill multiple pea sized holes to make a grid like pattern in the base of each. The holes can be anywhere from 3-6mm. This is for the worms to migrate between bins.
(TIP: I found the drilling of the holes made sharp uneven edges on one side from the pushed-out plastic, I melted these excess plastic edges down with a long gas lighter to smooth them over – leaving no sharp edges for the delicate worms. Not sure if overkill, but I’m a little OCD so yolo)
Next you’ll need to drill some small holes in your top lid, and in all bins just under their top lips (all the way around). This is for aeration. These holes should be small – so worms don’t escape and unwanted guests don’t join the compost party. 1-2mm is fine. I put these holes every 5cm or so. On the lid I drilled some holes in clusters as you can see in photo below.
Place two terracotta pots (or your chosen bolsters) evenly spaced in the middle of the bottom bin (the bin with the tap). Place second bin on top of these and repeat the process between the second and top bin – using 4 terracotta pots total. The pots allow for space between each bin level.
Important: place a few layers of damp newspaper on the bottom of the middle bin under the pots. This is to stop worms falling into the bottom bin, but allows liquid to soak through and collect in the bottom bin – liquid compost for the winnnnn.
In my photo below you will notice my middle bin is already filled with compost, this is a completed layer of compost – which was the top bin – that I have now swithced to the middle for the worms to migrate upwards to start feeding in my top bin (this is an advanced step mentioned in more detail below). Your middle bin will only have newspaper and two terracotta pots to start.
The top bin can now be filled with bedding for your worms! (see more bedding info here) Lastly place the bin stack on top of some old pots or bricks to keep it off the ground (as pictured). You will also notice in the photos I have a tray (or extra bucket lid) sitting underneath my worm farm, I use this as a water barrier. Keep the lid filled with water so ants and other crawlers cannot climb up into your worm farm.
You can add levels repeating these steps as your farm grows. Be sure to place your farm in the shade and in a sheltered position from rain.
Worm bedding and the difference between greens and browns
Bedding is the most important part of your bin to keep your worms happy. So what is the bedding? Bedding is what the worms live in and consists of what are commonly labelled greens and browns. Browns are the dry bedding that suck up the extra moisture in the worm farm keeping it healthy. The green is any organic waste from the kitchen which often causes moisture in the bin. Both beddings are eaten by the worms to produce worm castings (or poo).
You start your worm farm off with just browns until the worms settle in. It is important that you keep the bin two thirds brown and one third green to keep the right moisture levels and to sustain an ideal home for the worms. The bin should be kept moist so that if you squeezed the contents with your hand it should make a drop of water, it should never be dripping.
Here is a list of the brown bedding materials that are perfect for your worms house:
- Damp newspaper often shredded (put in dry if bin is too wet) and Soft cardboards
- Horse and cow manures
- Egg cartons, no labels
- Toilet rolls
- Coco coir (coconut husk, great for retaining moisture)
- Sugar cane mulch (worms love this stuff)
- A bit of soil or compost
- Bark and leaves
Which worms are for composting
So which worms do you put in your farm? The most common composting worms are called red wigglers. These small red worms live on the surface of soil and use objects such as leaves to hide. Unlike the common garden earthworm, these little worms do not burrow. The red wigglers reach maturity at around 3 months and can produce 2-3 cocoons each week (“Worm Reproduction & Development – Compost-ology – City of Euless”, 2019). These cocoons take around 11 weeks to hatch.
Be sure not to turn (or mix) a vermicomposting farm as this may dislodge or damage cocoons thus this will affect the reproduction rates of your farm. You can gently loosen up the natural soil compaction from time to time. Earthworms can also live in your farm but they will need more soil or worm castings first to burrow in, they will also help to break down your scraps.
What to feed your worms from the kitchen
The most common question when it comes to worm farms is what do we feed them, remember this is not a compost heap in which you can chuck anything, it is the worms house and we want them to stick around. Worms eat most organic waste from the kitchen with a few exceptions. They do not like acidic foods such as citrus or tomatoes, so keep the orange peels for the bin. Worms do not eat meat, dairy or oily foods so avoid putting these in your farm as well. Starchy foods I have found get left and don’t always seem to disappear in my worm farm – such as potato peels – I tend to avoid these if I have other scraps handy.
Worms have tiny teeth and digestive systems so the more digestible foods you feed them the happier they will be, such as cutting scraps up fine or blending. It is important that you do not start to feed the organic waste from a family of four to a newly established farm, as the worms need time to settle and multiply to cope with this much waste. Once you start feeding your worms you will quickly work out how much you can feed them by how quick the scraps are disappearing. Be sure to gently bury your scraps in the soil or under newspaper to avoid smells, attracting fruit flies.
Here is a list of green scraps your worms will love:
- Fruit pulp from juicer (not citrus)
- Fruit scraps and off cuts (apple cores)
- Vegetable off cuts and scraps (avoid potato and tomato)
- Lettuces and salad scraps
- Used Coffee grounds
- Tea bags
- Crushed egg shells (pull off white lining if possible)
- Banana peels
- Most herbs
- Avocado skins (their favourite)
- Watermelon rind
How to add another level and move worms once compost is ready
Well this is the fun part, your compost is ready! Or you are keeping your worms so happy they are multiplying and you need more bins producing worm poop at once. How exciting.
Simply swap the top bin (full of worm and compost goodness) with the empty middle bin, which will now be your top bin. Start by adding some bedding to the top bin and some food scraps. Over time the worms will crawl up through the holes to the top bin that is now being fed scraps, to leave the middle bin full of compost and no worms. This process does take some time and may still require some manual worm picking. Don’t be lazy Janice.
Alternatively you can manually sieve out the worms from your compost and add them to the new top bin – this is a delicate process.
Making and using worm tea or leachate
Leachate is the excess liquid that comes from your worm farm, this is not worm tea. When I first started my worm farm I never found any excess liquid in the bottom bin and did not understand how to get any leachate. Keeping your farm at the right moisture levels should NOT create a full bottom tray of liquid. The best way to extract your leachate is to water your compost bin once the worms have moved up a level to a newly established bin. This is once your compost is ready. Watering once a week will give you plenty of leachate in your bottom catchment to use as needed. Once you have your leachate it should be diluted into water ratio 5:1 – like you would do with a Seasol solution.
Worm tea on the other hand requires you to take one heaped handful of worm castings and subsequently soak them in about 5 litres of water to extract all the goodness. Worm tea is like liquid gold for your plants and vegetable gardens and is one of the best liquid fertilises you will find. This ‘tea’ contains plenty of good bacteria and microbes as well as all the best nutrients and minerals your plants need. It also works as a foliage spray and doubles as a natural insect repellent to keep your plants healthy both above and below the ground. A gardeners holy water. If you have a good vermicompost stash going you can routinely add a spoon to your usual watering regime (don’t overdo it – maybe once every third or fourth water will be el primo).
Pests and unwanted guests
Pests in indoor worm farms are minimal, but if you have a patio or outdoor farm pests are something to keep an eye out for.
Fruit flies tend to be present in any worm farms due to decaying fruit and vegetables. These little flies will not do any harm to your worm farm – so don’t fret. Try burying your scraps with soil or cover with newspaper to avoid attracting fruit flies.
Another pest that has been common in my worm farm is mites. Mites are tiny crawling bugs that also feed on decaying matter. They come in the hundreds and breed very quickly if the conditions are right. Mites like wet and acidic conditions so if you have an infestation don’t overwater, let you farm dry out a little until they leave. Another great way I have found to get rid of mites is to place a large watermelon rind on the top of your farm this will attract the mites, you can then remove it and put it in the bin – be sure to pick off any worms. Repeat this if you have an infestation.
Another common problem in most of Australia. These little bastards will get in to everything and anything they can find. My greatest foe.
The best way I have found to control ants is by sitting your worm farm over a ‘water bath’. Place a tray or lid of water (as shown in my DIY steps) underneath your farms base/legs so ants cannot cross the water to climb into the farm. If you have an ant problem the best way to get rid of them is to soak the farm, ants will escape quickly up the sides or drown. Not the most ideal solution for your worms, but ants will take over the farm quickly if not dealt with. Let the water drain out the bottom as you hose it to get rid of any ants and nests.
I’ve tried a protective ring of ant dust around my farms but this didn’t work. Maybe they built a bridge of corpses over it. I don’t know. Clever little buggers.
Maggots can sometimes appear in your farm. These are fly larvae. When building your farm be sure to drill small aeration holes rather than large ones, in order to avoid flies entering the farm to lay eggs. If your bin is too wet or being overfed – causing rotting food – this is the perfect condition for maggots to thrive. Maggots can generally be easily removed by placing in a lure (milk soaked bread) and then removing this once covered in maggots
Do worm farms smell?
The simple answer is no, worm farms should not smell hence they are suitable for indoors. A healthy worm farm should smell like garden soil. If your worm farm smells then you will need to do some troubleshooting. Is the farm too wet? Are the worms being overfed? Are you burying your scraps? These are some questions to find the source of why your worm farm is smelly.
Keeping the right balance of greens and browns in your farm should ensure it has a neutral smell. Overfeeding is the main cause of a smelly worm farm, as the food will start to rot when the worms cannot keep up. Also be sure to check the foods to avoid list as these foods can create unwanted smells in your bin.
And that’s all there is to it. Seriously, vermicomposting has been a game changer for me. Fun, rewarding, and awesome for both the environment and your plant garden. Get amongst it!
Miss Pot Plant xoxo
Worm Reproduction & Development – Compost-ology – City of Euless. (2019). Retrieved 27 August 2019, from http://www.eulesstx.gov/composting/vc_reproduction.htm