Items needed to make a worm farm
Worm Farms

How to make a worm compost bin – my diy project

To buy a worm compost bin or make your own? That is the question.

There are commercial worm farms available on the market that don’t break the bank, costing from $AU60 to $AU80. I have yet to try them out, but I believe they are adequate for the needs of home composters or the hobby worm farmer.

However, if you are going for the cheapest option available, then a home made compost bin will cost less and give you the satisfaction of using something you have made yourself.

A diy worm farm can be as simple or complex as  you want to make it. In the spirit of recycling, you can re-use items you have lying around your house. This could be wood, old baths or tubs you no longer need.

For this project, I have decided to make a simple plastic compost bin, with a second tub to catch the excess water run off (leachate).

Without further ado, lets get into it.

Step 1: Gather the items you will need

Items needed to make a worm farm
Items needed to make a worm compost bin
  • 2 opaque tubs with a lid
  • a drill
  • newspaper and/or cardboard
  • spray bottle with water
  • brick or wood block
  • newspaper to use as a blanket
  • garden lime
  • soil or vermicompost
  • small amount of food scraps

For this project, I am using 2 x 50L tubs. If you want a small compost bin for inside the house, to be able to hide in a cupboard, then you can go as small as 20L. I had trouble finding an opaque 20L tub with a lid, so I went large.

It’s important to find an opaque tub as compost worms are sensitive to light and require a dark environment. However, if you are intending to keep your compost bin in a cupboard, then it’s less important for your compost bin to be opaque as the cupboard itself will be dark.

Cost of project

Of the above items, I bought the tubs, the worm eggs and the dolomite lime. Everything else I got from around the house and from my rubbish bins.

  • tubs $AU7 each = $AU14
  • worm eggs = $AU24.99
  • dolomite lime =$AU7.47 for 5kg bag
  • Total cost of project = $AU46.46

This shows that it is possible to make and stock a diy compost bin for almost a third cheaper than it costs to buy a commercial worm farm.

 

Step 2: Prepare your materials

The next step is to get the materials ready to use.

Cardboard

I am in the habit of tearing up cardboard as I find it. This saves me from a long cardboard tearing/cutting session.

When you are ready to use the cardboard, it needs to be soaked and drained. Lots of people recommend soaking cardboard overnight to make sure the water gets through all the layers. If you’re like me and not very organised, then soak it for at least one hour before setting up your worm farm. It then needs to be drained to remove the excess water. The water content should be similar to a wrung out sponge. Draining can be done by wringing the cardboard with your hands or by dumping the cardboard on the lawn to self drain (if you don’t have a lawn, try using your shower stall).

I estimated how much cardboard I would need by filling up the tub half way. Turns out that I underestimated by half, as the volume of the cardboard shrunk when wet. Next time, I will fill the tub up when estimating how much I will need, as it is better to have to much that to little.

Which cardboard should I use?

For my first bin, I was high on the recycling bug and used any cardboard that came my way. This included shiny cardboards and takeaway coffee cups.

My observation is that these cardboards don’t break down very well and some of them have a plastic coating on them don’t bread down at all and which I then have to pick out of the vermicompost.

There is also the old saying “what goes in, must come out”. While these cardboards don’t seem to affect the worms, they are still there. Whatever compounds are used to make these cardboards will end up in your vermicompost and will be put on your garden.

If the worms ingest the compounds and you use them for fishing or to feed the chooks, then the compounds are introduced into your food chain.

So, my new policy is, if it looks glossy or highly processed, leave it out.

Newspaper

I tore up three newspapers into 1″ strips. It took about 5 – 10 mins to do this. This turned out to be more than I needed, which is ok. I will save the extra Torn newspaperfor new bedding when I harvest.

I happen to have a shredder in the house, which my mum used to shred important papers. I like using shredded paper as I think it sticks together a little less, but I decided to tear the paper this time for those of you who don’t have a shredder. Either way is fine. I wouldn’t recommend getting a shredder for home worm farming, unless you intend to get serious about it.

I chose not to soak the paper this time. Instead I sprayed it with the hose and fluffed it around to make sure it all was wet. This way I could avoid having to squeeze out excess water. If I was starting with live worms I would not do this but as I have bought worm cocoons, I think there is time for the moisture content to even out between the paper and cardboard before the cocoons hatch.

Update: turns out there where quite a few juvenile worms in the bag and even some adults.

Prep the tubs

This is the part where you get to mess around with tools. At the grand old age of 42, I have purchased my first drill and this is the second time I have used it. Once I got the hang of it and learnt how to use the controls, it was very simple and straightforward to use.

Firstly, set one tub to the side to remain intact. This is going to be the drainage tub to catch any leachate. In the second tub, we are going to use the drill to make airholes in the top of the tub and drainage holes in the bottom.

Air Holes

Worms and the microbes they co-habit with are aerobic creatures. This means they need an adequate flow of air in their environment (bedding) to survive. There are two ways to do this: drill lots of holes in the top and sides of the tub, or cut out sections of the lid and tub and cover the holes with fly screen.

Experienced worm farmers insist that the first method doesn’t provide enough air to the farm. However, I have used this method from the beginning and have harvested a nice amount of vermicompost from my tub. So, I will argue that it is sufficient for a home farm set up.

The trick with air holes is to make them large enough to let air in, but small enough to prevent black soldier flys from entering your farm. While black soldier flies are also great composters and don’t spread disease like regular flies, they will take over your farm, especially in summer and eat all the food intended for the worms. There is also the ick factor to consider, they look like ginormous maggots.

I am using a 5mm drill bit for this project and will report back on the results.

Holes drilled in worm farmI made two rings of holes around the top of the tub as shown in the photo to the right. I chose not to put holes in the lid as my farm is going to live in a dirty, dusty shed and I’m worried about things falling through the holes, but you can feel free to aerate your lid as well as the sides.

 

Drainage Holes

Holes in base of worm farm

Next, we will put drainage holes in the bottom of the tub, to allow excess water to drain out.

Worms breathe air through their skin, therefore they need to be kept in a moist environment to allow for air transfer. However, we don’t want the farm to flood, as the worms can be drowned or driven out of the bedding and we will end up with boggy, soggy vermicompost.

Water will be introduced into the farm in two ways. First, we will be spraying the top of the farm with a spray bottle, at least once per week, to keep the moisture content up. Secondly, the food scrapes we will feed the worms will release water as they decompose.

I don’t think it matters how many holes you add. However, if the base of your tub is raised, make sure you put holes in the lowest point of the base.

Step 3: Putting it all together

Worms added to worm farm

I set this bin up using a layering pattern. I put a layer of cardboard about 2″ thick, then a 2″ layer of newspaper, followed by the rest of the cardboard. At this point, I spread the cocoon rich material (brown) over the cardboard, along with some used tea leaves (red brown) as food, vermicompost to provide microbes required for decomposition and a sprinkle of lime (white) to maintain a pH neutral environment. I then topped it of with another layer of newspaper.

Step 4: Find a shady place

Compost worms are sensitive to temperature. Their ideal temperature range is 15 – 24°C (60 – 75°F). In this range, they will have optimal eating, pooping and reproduction.

Outside of the ideal temperature range, worms can survive highs of 35°C (95°F) and lows of 1°C (34°F). The further the temperature gets from the worms ideal range the lower their activity becomes.

Beyond these ranges, your worms will begin to die.

For this reason, its important to find a shady place to keep your worm farm. If you live in a place that snows in winter you should keep the worm farm inside. If your summers are hot you will need to consider ways to keep your worms cool.

Next, we wait

There you have it.

Over the next 3 – 4 months our worms are going to eat, poop and be merry. At the end of that time we will be rewarded with a tub of black gold (i.e. vermicompost or worm castings).

All we have to do in exchange for this is to make sure our worms are feed, watered and not to hot or cold.

I would love to hear how you get on making your own compost bin. If you have any questions or used different techniques that have worked for you then please leave a comment below and I will get back to you.

I wish you all happy Wormicomposting.

 

 

 

 

14 Comments

  • Robert M Doyle

    This post is just what I’ve been looking for! I actually was thinking about this the other day. I am an avid gardener. It is more than a hobby; it is a way of life. If someone is truly health-conscious, they will have a garden and try to grow most of their food if they can and if they have space. I want to get there. Worm castings are very important for adding to the soil. This post is quite helpful and something I plan to refer to in the future.

    • Dianna

      Hi Robert

      I am glad to meet you Robert. Its obvious that you are passionate about gardening and growing healthy food. It is true that worm castings are important for that. Plants grown with worm castings will grow a third bigger and have better natural resistance to diseases.

      I look forward to hearing how you get on with your own compost bin.

      Happy Composting
      Dianna

  • Pamela Muir

    I like gardening but not understanding why I would make a worm compost. My thoughts of worms I expect I am wrong is that they eat roots. Your website information on how to make a compost is really good and very informative. You obviously have a passion and studied about worms. Will be interesting to see why this is necessary, I expect lots of other people know why but being an amateur gardener suppose I will have to learn, Very Good

    • Dianna

      Hi Pamela, thanks for your comments.

      There are thousands of species of worms and they all fill a different niche in the environment and eat different things. My particular focus is on compost worms. These guys live in the top 12″ of soil and feed on rotting materials such as leaves, grass, fruit & veg and dung. If you put these worms in a bin as I have described, you can feed them you kitchen scraps.

      Why? People do it for various reasons. As a gardener, you may choose to farm compost worms for their casts (poo). Worm casts (A.K.A vermicompost) are full of good bacteria that builds up the quality of your soil. Vermicompost can be used as a soil amendment to replace chemical fertilizes, which tend to decrease the quality of the soil.

      I will be writing posts covering these questions in the future, so stay tunned.

      Happy Composting
      Dianna

  • Josh

    Very insightful post…Like how much detail you go into, in order to explain the process clearly and simply which is particularly useful for someone like me who would be doing this as a beginner.

  • vivek

    While gardening isn’t a huge hobby of mine I am mildly interested in it. This sort of a DIY project is something I love doing!

    I’m curious as to how exactly you would use this in gardening? Apologies if I missed your answer to this previously!

    • Dianna

      Hi Vivek

      Thanks for your question.

      Worms have evolved to fill a special place in nature. They feed on decomposing materials such as plants and dung and feed the nutrients back into the soil via their own poo. Worm poo is also known as worm castings or vermicompost and is considered to be the black gold of the gardening world.

      Most chemical fertilizers kill of the beneficial bacteria that is in the soil and in doing so they decrease the quality of the soil. On the other hand, the worms gut is full of beneficial bacteria and they transfer the bacteria into their casts. Worm castings are able to renew barren soil, as they contain beneficial bacteria and the nutrients plants need to grow.

      Let me know if you give it a go. I love hearing about peoples experiences.

      Happy Composting
      Dianna

  • Maran

    The had no idea about this but the way you had presented it made me read the article. It was very informative and i could see the passion you have for this. Great work! All the best.

  • Craig

    This is absolutely awesome, and so much more affordable than any of the ones you can buy from Home Depot etc.

    One question I do have though. I live in the city and have a very limited space. This compost bin will easily fit in that space behind my home, but how dependent is it on getting a lot direct sunlight? I know generally getting sunlight really helps move the process along because it heats things up…Is it an absolute necessity though? I don’t get a ton of direct sunlight…

    • Dianna

      Hi Craig

      Thanks for your question. I believe you are thinking of hot composting or traditional composting, which is indeed aided by sunlight.

      Composting with worms is a different matter. Compost worms are sensitive to temperature. If they get to hot they will die. For this reason it is recommended to keep worm farms in a shady location.

      So, to answer your question, your space sounds like the perfect location for a worm farm.
      If you have any further questions feel free to email me at dianna@wormicompost.com.

      Happy Composting
      Dianna

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