Can you have too many worms in your compost? | Why Worms Gather

It is rare for there to be too many earthworms in your compost bin if they are allowed to naturally enter and exit from the base. They will balance out their own population based on the amount of food available. If you are adding composting worms to your bin, their population can increase rapidly but will level out over time as the compost breaks down.

Worms can gather in large groups if the compost is out of balance, too wet, too acidic or too hot. In this case you can take action to improve your compost and encourage the worms to spread out.

This article will explore how worms get int your compost, the benefits of having more worms in your bin and why large groups of worms can end up on the surface.

How worms get in a compost bin

Worms can get into your compost naturally or by introducing them. Here are the top ways that worms find their way into your compost.

1. Eggs are transferred from ground soil

Worm eggs can enter your compost bin from the ground soil if you are adding old your own soil to the compost or if you are adding old plants and weeds. The soil that surrounds the roots can carry worm eggs which will allow them to hatch and live in your compost.

2. Old compost material is added

Old compost material can carry both worms and their eggs. I like to add old compost to my new piles to speed up the breakdown process because it carries both worms and soil bacteria. I find that even a shovel full of old compost will speed up the breakdown process of my new compost. This is because I am directly adding earthworms to the mix.

3. They crawl their way up into the compost bin

Worms can crawl up from the ground soil into a compost bin with an open base. Homemade bins that are on the ground or plastic bins with an open base are easy for worms to find their way into. They will seek out the organic matter and crawl up from the healthy ground soil.

4. You add composting worms yourself

Adding composting worms yourself is another way that worms find their way in. Composting worms including red wigglers have different behavior than earthworms and prefer a damp, environment with lots of organic matter. They live in groups and digest organic material fast.

Why large groups of worms appear in your compost bin

Sometimes you can open your compost bin lid and find that there are lots of worms appearing on the surface. Here are the reasons why you can get lots of worms in one place.

Spring breeding

Worms can appear on the surface of your compost bin after a long winter. If you open your lid for the first time in spring you can sometimes see layers or groups of worms at the top.

This is because compost bins are a great hideout for worms in the winter. The top layers can warm up as the sun arrives in spring and make a great environment for worms to start to breed.

They can breed rapidly when spring arrives and you may see loads of tiny baby worms at the surface. It may seem like there are too many worms in your compost bin it is actually no problem.

They will eventually crawl back down to the ground soil as the population increases or as the organic matter is digested. You can scoop them out into another area of your garden or add them to your new compost pile. Either way the population will naturally balance out over time.

If you have added composting worms to your bin, they will also find their own balance. The population of the worms is controlled by the availability of food and they will not breed beyond this. This means that as the organic matter in the compost bin is broken down, worms move away to find more food and slow their breeding rate.


Worms can gather in one area of your bin when the temperature gets too high or if the compost materials start to lack oxygen. Worms can gather to feed on food scraps that have concentrated in one area or will gather for protection if conditions are too hot, cold, dry or damp.

To help worms to spread out more evenly throughout the compost it is important to mixing the pile gently and often. This will help to spread the food scraps, moisture and oxygen throughout the bin and encourage the worms to spread out to feed.

Too much water

Worms can start to crawl to the top of your compost bin or even find shelter in the lid when the compost becomes too wet. Compost can become too wet if you add too many food scraps or green material. Balance this out with brown materials such as straw, hay sugar cane mulch or fall leaves.

Earthworms in your compost

It is rare that too many earthworms will crawl up from the ground soil at any one time to live in your compost. They prefer not to live in dense groups like composting worms and can travel to find their food.

Worms in hot compost

Worms do not like to live in a hot composting system but will crawl out to cooler regions of the compost or out of the base. They will crawl back in when the compost cools and matures to help to finish the composting process. If your hot composting system is on the ground soil then this will happen naturally.

Worms in your compost bin – Pros

Here are the top benefits of having worms in your compost bin. I would never worry about having too many worms in your bin because they naturally balance their own population and offer so many benefits to the composting process.

1. Worms help to break down organic matter faster

Worms are master digesters and break down loads of organic material. Worms will help your compost pile to break down faster and have it ready sooner for use in your garden.

2. Balance out soil bacteria population

Worms feed on soil bacteria that are feeding on the organic matter. This process helps to balance the population of bacteria and break down organic matter faster.

3. Release nutrients ready for plant absorption

Worms digest organic matter and to capture and release nutrients into their castings in a way that allows plants to absorb them. This process incredible and leaves your resulting compost richer and the perfect ingredient to improve your soil drainage, structure and fed your plants.

Can you have too many worms in your compost? | Summary

You cannot have too many worms in your compost because they will naturally balance their own population if they have a way to escape. As the compost breaks down and there is less organic matter to digest, worms will naturally find their way out of your bin down through to the ground soil.

If you have a raised compost tumbler off the ground and the worms are grouping you can scoop them up and transfer them to another area of your garden.

Happy composting.