A Guide to Vermicomposting

With the whole world becoming more conscious about waste and everything from allotment to greenhouse gardening seeing a huge revival – compost is king.

But you don’t have to work alone. With the help of some wriggly little friends, you can have a finished material that’s waste and money-saving as well as environmentally friendly and better for plants!

What is vermicomposting?

Vermicomposting is the use of decaying food and vegetable matter, bedding materials and worm castings to produce fertilizer.

Worm castings, also known as vermicast, worm manure, and even worm humus (don’t spread it on a cracker, it’s worm faeces!) are the end result of the material that a worm ingests.

multi-coloured gummy worms in a pile
Not this kind of worm, sadly!

And this ‘worm manure’ is an end product that’s fairly easy to achieve. It can be a great way to fertilise your garden and houseplants and reduce waste.

Vermicomposting usually involves using red-wigglers (and sometimes white worms) to speed up the decomposition process of composting. Compost creates organic fertiliser from natural waste to improve soil health.

These worms (Eisenia foetida or Lumbricus rubellus), are the best because they are able to reproduce effectively while in captivity.

So…is Vermicomposting Worm Farming?

Yep – worm farming, also known as vermiculture is the process of converting natural waste to a useful by-product, namely fertiliser.

Which begs the question:

Why Would You Want to Vermicompost?

Although getting your hands dirty and covered in worms might not sound like everyone’s cup of tea, there are a few people who vermicomposting will attract.

They are gardeners, farmers, compost merchants and generally anyone with a green thumb. But let’s break down the benefits and how vermicomposting actually works.

Benefits of Vermicompost

Vermicompost is a great alternative to non-natural fertilisers which often contain chemicals and pesticides. Instead, vermicompost has highly concentrated:

  • Nitrates
  • Phosphorus
  • Magnesium
  • Potassium
  • Minerals like manganese, zinc, copper, cobalt, borax, carbon, iron, and nitrogen

But what does that actually mean? Well, first off it means its power food for plants.

Vermicompost is quickly absorbed and some gardeners say even as little as a spoonful of vermicompost is enough to feed a plant. It’s about three times as effective as regular compost!

Plus, with no chemicals, vermicompost shouldn’t burn or damage plants and it allows you to recycle and make use of natural waste. It’s a win-win!

So what about those of you who have more than just a bit of organic waste to deal with?

A hand holding a trowel adding compost to a yellow bucket
Credit: Unsplash

Large-scale vermicomposting

Whilst most of you might want to vermicompost to use up food scraps and waste, vermicomposting has very useful applications on a larger scale, too.

Throughout Canada, Italy, Japan, Malaysia, the Philippines, and the United States, vermicomposting is used. It’s not only a profitable use of food waste but an environmentally-friendly one too!

For large-scale vermicomposting, the three most popular methods are:

1) Windrow system (outdoors in piles)

2) Raised bed (usually outdoors, in raised planters or beds)

3) Flow-through system (indoors in a pit)

Vermicompost quality

Obviously vermicompost quality can range depending on the food waste that goes into it. A good way to measure the quality of your compost is by porosity and bulk density.

Also, think about what food scraps you’re putting in. The more organic the waste at the start of the process, the cleaner your compost will be for your plants.

Vermicompost can also be added to water to create compost tea or worm tea for watering plants.

planter bed with potted plants and shoots coming out of soil
Credit: Markus Spiske

Effects of vermicompost

Once you have your finished compost, there are a wide range of uses. It’s great your own starter seed mix as it’s so nutrient-rich. Or it can act as a valuable soil amendment if you want to change nutrient and Ph levels.

You can even use your finished compost right away or store and save it. Studies have even shown that plants fed with 50% vermicompost show more significant growth than those treated with chemical-rich fertilisers.

So now that we know the effects of vermicompost are so great, it’s probably time to show you:

How to vermicompost

In this next section, we’ll run through all the unprocessed material you’ll need as well as the more practical elements. And of course, we have to start with:

Worms

A good rule of thumb is one pound of worms per square feet of compost bin. Just be aware, you can’t just use the common worm, though!

The type of worms you’ll need are specifically manure worms. These baby worms are called ‘red wigglers’ and are usually sold by the pound.

Another way to figure this out would be to consider that red wigglers can eat about half their weight in food each day.

So if you have a compost bin that’s 10 cubic feet, you’ll need 10 pounds of worms. To keep up with them, you’ll need to provide 5 pounds of food waste a day.

Soil

To create healthy soil, you’ll first have to have a bit of starter in which to place your worms.

So while your worms will create soil and compost with their discarded worm castings, you can’t just put them straight into a bin. Instead, you’ll need bedding materials –  which we’ll discuss below.

Once you get them started, you’ll have vermicompost you can add to your garden soil in 3-6 months from scratch.

Compost Material: Waste and food waste

In general, compostable materials include:

  • Organic waste
  • Organic materials
  • Food scraps (including fruit scraps)
  • Vegetable waste
  • Yard wastes
  • Grass clippings
  • Kitchen scraps
  • Egg shells

So anything that can decompose and is organic matter can be added to compost piles. Just remember not to add dairy, oil and meat waste (as they’ll smell), and that green waste may heat up your compost bin.

Don’t let your bin get too hot or dry out, or get too cool in colder temperatures – the ideal range is 60-80 degrees F.

Don’t add more food waste until you’re sure your worms are effective compost turners! Until then, you can store organic waste in a separate bin or even a coffee cafetiere.

Now, during this decomposition process, you might notice some new friends buzzing about – fruit flies.

This is why it’s suggested that you always buy (or build) a compost bin with a lid. Otherwise, you can always create a dish of apple cider vinegar and dish soap nearby to trap fruit flies during the composting process.

Plants

Not only can you use vermicompost to help with plant growth, but you can also use plants green waste to help with vermicompost. It’s a beautiful little circle of life.

So grab clippings from any dead plants and add them to your compost bin. Just make sure not to substitute genuine organic food waste for cuttings. Your worms still need to eat!

As for using vermicompost, it can help drain thicker soils, retain moisture in sandy soils, and they can even help with soil structureBut it’s not right for everything.

When To and Not To Use Vermicompost

  • Indoor plants –  Use when starting winter plant growth indoors but be careful. One, they might not need it as badly, and two, too much compost (even vermicompost) may burn more delicate plants
  • Plants with healthy soil – Don’t use vermicompost (too many nutrients can be toxic to plants, check your soil levels first)
  • Sick plants – Vermicompost can help kill pathogens
  • Actively growing plants – Sprinkle a bit of vermicompost on topsoil
  • Starter seeds – Great for a nutrient-rich boost

Bedding Materials

To get your vermicompost bin started you can use a mixture of dry bedding and moist bedding.

You just need to make sure that your bin isn’t either too dry or too wet. Bedding materials need to be non-toxic and easily digestible. These might include:

  • Shredded paper, newspaper, and cardboard (try to avoid any with bleaching or printed ink on it)
  • Compost, peat moss, and yard waste
  • Coconut husk
  • Straw and hay

To add moisture to this unprocessed material, you can even wet and then squeeze dry(ish) items like shredded paper.

plastic compost bin with grass cuttings next to white clapperboard wall
Credit: Flickr

Temperatures and moisture

What you don’t want is excess water in your compost bin. The moisture content and ambient temperatures need to be kept just right to keep your worms productive (and alive!).

Adding a bit of water to handfuls of soil will be necessary, but keep the range of temperatures between 60-80 degrees F (like we mentioned earlier). Both freezing and too hot weather can kill off worms. You can spray down your bin every so often to keep it moist.

To combat high heat, keep an eye on your worms and potentially cut back on feeding materials, especially green waste. These might be causing your bin to heat up and food will go wasted. You can reverse this plan in winter.

How to Create and Maintain a Worm Composting Bin

In this section, we’ll go through how to gather up everything we’ve just talked about and make your very own vermicomposting bin. These make great additions to garden greenhouses to keep your potting mix nearby.

Vermicomposting Checklist

  • Bin (made from plastic or wood)
  • Red wriggler worms
  • Bedding materials
  • A pair of gloves
  • A dish with apple cider vinegar and dish soap

How to set up a worm bin for vermicomposting

If using a pre-existing bin

  • Make sure it hasn’t stored chemical or pesticides before
  • Drill several small holes in the sides and bottom for ventilation
  • Attach a lid
  • Fill with worm bedding and eventually worms

Make sure not to use anything built from aromatic woods like cedar or redwood!

To build your own vermicompost bin from scratch, just follow the video below.

Or you can check out our post on the ten steps to create your own compost heap!

Harvesting Vermicompost

In around three to six months, your vermicompost should be ready to harvest and be put to use.

You’ll notice the change once it has turned a rich, dark colour similar in texture to soil. But to harvest your vermicompost, first you need to move your worms.

You can do this in a couple of ways:

1)Move all composted material to one side of your bin and add new bedding materials to the other side. The worms will naturally migrate to the bedding.
2) Empty the entire compost bin onto a plastic sheet. Separate the compost into piles. Wait for worms to migrate to the bottom and harvest your vermicompost from the top.

Vermicomposting: To Recap

Vermicomposting is an easy and rewarding activity. It’s good for the environment and good for your garden. So whether you’re at home in the country of a city apartment, you can reap the benefits.
And if it’s greenhouse growing that you’re looking to use vermicompost for, check out our range of greenhouses via the button below!

FAQs

Vermicomposting, or composting with worms, just requires you to:

 

  • Buy or construct a compost bin from wood or plastic
  • Buy red-wriggler worms
  • Shred bedding materials like cardboard and coconut husks
  • Feed worms half their weight in organic food waste and scraps per day
  • Harvest nutrient-rich organic vermicompost in 3-6 months

 

Yes - the great thing about vermicomposting is it can be done at scale, or in a small bin if you live in a city apartment or somewhere with a shared garden.

All you really need is a bin, worms, bedding materials and food scraps to feed them.

While the positives of vermicomposting far outweigh the negatives, a couple of drawbacks might be:

 

  • Takes 3-6 months to get finished materials
  • Unless done at scale, it's effective for dealing with garden waste
  • Fiddly to separate worms from compost when harvesting

 

The rule of thumb is that you'll require 1 pound of worms square foot of compost bin and that they eat half their weight a day. So if you have 10 pounds of worms in your bin, they'll need 5 pounds of food waste a day.