Vermicomposting: How many worms do It needs? - UGR

How Many Composting Worms Do I Need?


If you want to maximise the amount of waste you compost in your worm farm, then it’s useful to know how many worms you will need. In her legendary vermicomposting reference guide, ‘Worms Eat my Garbage’, Mary Applehof provides the following formula for calculating how many worms you will need:

Worms: Daily Garbage ratio    =     2:1

To put that into figures, you will need 1kg of worms for every 500g waste you produce daily. You will note that worms are measured out in weight here rather than numbers. This is because it is much more practical. To give you an idea of how weight equates to number figures, approximately 1500-2000 worms makes 1kg.

Related: Worm Farm DIY: 4 Surefire Ways To a Thriving One

Now, worm populations require a certain amount of space to comfortably maintain their populations. They regulate their populations according to how much room they have. Populations will continue to grow if they have the space, but will plateau if their container is reaching maximum occupancy. In short, the more worms you want, the more space you will need.

Exactly how much space do I need for vermicomposting?

The logical follow up question is, how big should your container be? For every kilogram of worms (or 500 grams of food waste), The Worm Monger recommends you have 30 square centimetres of space.

A worm farm can take any shape, but the more surface area you have, the more air you will get circulating through your worm bin – and air is good for the health of your farm.* 

So, a shallow, longer farm will get greater aeration than a taller, thinner farm. Your decision will depend on the space you have available.

All too scientific?

While these measurements are a great guide if you are determined to eliminate your organic waste to zero from day one through vermicomposting, you really don’t need to be precise about things.

You may prefer to build your worm population over time for example (this is much cheaper – worms will double their population in around 60 days). Or grow your farm as you get to know your needs. This is perfectly fine. The added benefit to this approach is that you get to know the nature and habits or your farm better.

If you have space limitations (a common problem for city folk), then it might not be possible to have a farm large enough for all your food scraps.
That’s ok. In my experience, starting a worm farm will make you more conscious of the waste you produce – you will likely produce less waste once you start composting and will also come up with alternative ways to dispose of it responsibly.

* For more information on the best conditions for your worm farm, check this out.

Read next: Bokashi composting : The Pros and Cons for Urban Composters

Featured image from @wormup_thefineartofcomposting

About the Author


Hannah is a passionate lover of plants and has a firm belief that even the darkest corners of the concrete jungle can be greenified. Her penchant for composting and bad plant puns led to the creation of the The Worm Monger, a website that allows her to thoroughly indulge all these passions.

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