How Many Worms Do You Need to Start a Compost Bin?

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Worm composting has become an increasingly popular activity due to its money-saving capabilities, waste reduction and ease of use. Simply put, with just one worm bin, a few composting worms and plenty of food scraps, anyone can have organic compost for free, right in their own homes. 

However, all worm composters have to start somewhere, and it’s not always easy knowing how to create your own worm bin. 

You need to know what surface area you need to store the worm bin, how much waste you need to feed the composting worms, and of course, how many worms to start a compost bin. 

When it comes to knowing how many composting worms you will need to start your own worm farm, this depends on quite a few factors (the size of your bin, the species of composting worms you get, etc.). 

Thankfully, worms reproduce relatively easily and quickly, meaning that you will soon end up with more worms than you might have anticipated!

Just be sure that your vermicomposting bin is ready.

Read about how worms reproduce here.

Do I Need to Add Worms to My Compost Bin?

If you have a vermicompost bin inside of your home, then yes, you will need to add composting worms to the bin, as they will have no other means of access. 

However, if you have a worm compost bin outside, then it is only natural to wonder whether or not you will need to add composting worms to the bin. 

In actual fact, this depends on the type of bin that you have in place. 

If your worm composting bin is open at the bottom, and the worms have access to it from underneath, then there is a chance that you could attract worms by carefully creating a suitable environment for them within the worm farm.

You can attract red worms by ensuring that the environment in the worm composting bin is adequate, i.e. moist.

Since worms breathe through their skin, and their skin is relatively fragile, it is essential that their environment have a proper moisture balance in order for them to be able to breathe and move easily. 

You should also ensure that only organic matter goes into the worm farm in order to make organic compost.

Adequate worm food includes fruit and vegetable scraps, garden waste, etc.

You must avoid meat and oily foods, as these are difficult for the worm to digest.

Ensure that the worms always have enough food to want to stay in your worm farm. 

You will need to make sure that the bin is not too wet by adding adequate worm bedding such as coconut coir, shredded paper, tea bags; you can even tear newspaper strips for worm bedding. 

However, for those of us who would like to start worm composting as soon as possible, it would be best to add red wiggler worms to your bin and close it at the bottom so that the worms remain within the bin.

Remember to pay attention to the environment within the worm bin so that your red worms can live comfortably and happily.

How Many Worms Should I Get for Composting?

As mentioned, knowing how many composting worms you need for your bin will depend on the size of your bin.

But, how many red wigglers might you need on average?

The general rule of thumb is to buy one pound of worms for every 4 square feet of your worm bin. 

You should also consider how much food waste you produce. Red wigglers eat about half of their body weight every day. 

With that in mind, you will need to ensure that you have enough food scraps for red wigglers to live happily and that your plastic bin is big enough to balance out the pH level and the moisture levels between the food waste and the bedding.

Too much food will make the worm bin go mouldy, and no red wiggler will be able to survive in it. 

Therefore, the more people are creating food waste in your home, the bigger the worm population you will need, the bigger the surface area your bin will have to take up.

It would be good to do a family food waste audit before you buy worms. 

What’s more, different worm species will vary in size and community level – meaning the number of worms you can put in your new bin may depend on whether you’re looking for red wigglers, nightcrawlers, or otherwise.

worm composting bin

How Many Worms Do I Need for A Small Compost Bin?

When needing to know how many red wigglers you will need for your small composting bin, you should always refer to the size of the bin itself. 

Generally speaking, you should add one pound of worms for every four square feet of surface area. 

Remember to adapt the amount of organic waste you put in the bin with the worms based on the size of the bin and on how many composting worms are in there. 

Can You Have Too Many Worms in Your Compost Bin?

There is no set number of worms that would be too much for any one worm bin. You will notice that the number of worms in your bin will significantly increase over time, should their environment be good. 

However, you will need to ensure that the number of worms in your bin has enough organic matter to eat and live in comfort in order for their worm castings to be good enough! 

If you think that the number of worms in your bin is too high, then you can always take a few worms out and out them into a second bin.

Or, you could always enquire about someone looking for good baby worms for their own bin. 

How Long Does It Take for Compost Worms to Multiply?

Both European nightcrawlers and red wigglers can reproduce every 27 days, from mating to laying their eggs. This means that the population of worms in your bin can double in about sixty days.

However, before you worry about being overloaded with compost worms, it is essential to know that worms only live about 1.5 years.

This means that the population turnover is relatively frequent and manageable. 


Worm bins are a great way of dealing with garden and kitchen scraps and general food waste daily. They are so easy to make; even just a few small wooden bins will do the trick.

And, despite the special care needed for the worms to live safely and happily, the compost bins are actually very easy to maintain. 

The best thing that you can do if you are unsure about the amount of worms needed in your bin is to start small.

You can always adapt to your food supply for the worms, and remember that they will multiply quickly.