Does Turning Compost Kill the Worms in It?

Worms are decomposers that increase the nutrient supply to your soil. However, like most small creatures, they can die when placed under extreme conditions or stress. Turning compost needs to be done regularly, but what happens to the worms in your compost?

Turning compost will kill some of the worms in it. However, turning compost manually instead of using a tumbler should minimize the damage you do to compost worms. Also, turning compost makes food more accessible, which helps the worms rapidly increase their population.

The rest of this article will help to explain why you should turn your compost, why worms die in compost and the importance of worms in the first place.

Should You Turn Your Worm Compost?

Compost consists of lots of organic materials like kitchen waste, dead leaves, branches, and, occasionally, manure. 

Without turning compost over, these organic materials will undergo anaerobic decomposition— the decomposition of organic matter without air.

Anaerobic decomposition in your compost can stunt your plant’s growth or kill them if it gets bad enough. It’s also much more unsanitary than normal compost and will attract a multitude of flies.

One major benefit of turning over your compost is to speed up the decomposition process. By turning worm compost over, you move the worms and microbes around, exposing them to areas that haven’t fully decomposed. 

Although turning your compost can kill some of the worms in it, it’s a lot safer for them if you go the manual route as opposed to using a tumbler. Manual turning with (gloved) hands or a pitchfork agitates your compost pile much less and keeps more worms alive.

Do this biweekly to allow your compost to settle and continue the decomposition process between turns. As a general rule, you must turn your compost at least once a month.

Why Worms Die in Compost

Although worms can endure quite a lot, they aren’t invulnerable. When exposed to unfavorable conditions, your compost worm population might start to drop.

Although this can be worrying if you notice it start to happen, it’s vital to find out the root cause of their death. After identifying and correcting the problem, your worm population should make a recovery.

Here are some reasons why worms die in compost:

Poor Moisture Levels

Terrible moisture conditions are arguably the most common reason behind plant death. When compost has too much or too little water, your worms may drown or die from dehydration.

Worms generally love moist environments. However, green organic matter like vegetable and food waste often contains a lot of water, so you don’t need to supplement the moisture in your compost.

As a result, adding too much water to compost can cause worm death in droves, especially if they are “trapped” in compost bins. The water may pool at the bottom of the compost bin if there are no holes to facilitate drainage.

On the other hand, too little water also causes worms problems. Worms are largely made up of water so having sufficient moisture is key.

How To Fix

If your compost is too wet, you need to add more organic matter to it. This dry compost will soak up the extra moisture, lowering the chances of worm death. Although this will lead to some uneven decomposition, the benefits outweigh the downside.

When it’s too dry, wet your compost until there are visible signs of slight dampness. The best way to do this is with a watering can.

Extreme Temperatures

Worms seldom survive extreme temperature fluctuations as their body composition can’t endure environments that are too hot or cold. These decomposers thrive best in moderate temperatures. Optimally, your compost pile should be between 53.6℉°- 77℉° (12℃-25℃).

Too much heat and your worms will get cooked to death. On the other hand, if they’re continually exposed to cold temperatures, they may freeze.

How To Fix

If your bin is in the path of direct sunlight, try to move it to an area with some more shade. Interestingly, worms that feel the compost getting hotter will often quickly move to avoid death, so if your compost pile is hot, wait until it gets cool to add new worms.

During cold weather, move your worm compost bin to an insulated shed or a garage to provide some insulation.

Not Enough Air

While worms create burrows for increased air circulation, they often still need external aeration measures to stay alive. To this end, manufacturers often include holes in their compost bins to aid aeration, but they sometimes get blocked.

A lack of oxygen in bins can cause worms to die rather quickly. Additionally, compost used as bedding can become compacted due to the decomposition process. This compact structure can also lead to oxygen deprivation.

How To Fix

Remember to keep a close eye on the holes in your compost bins. If they’re blocked, use any means necessary to clear them up.

Additionally, regularly turn your compost to prevent it from becoming compacted. These measures increase airflow between soil layers, facilitating worm growth.

Too Much or Too Little Food

The amount and quality of food worms feed on is also a vital factor. As the worm population grows, they will need more food. If there’s insufficient food, worms will start to eat their castings. These castings are toxic to worms and will kill them.

Conversely, too much food can also cause worm death and will make your compost bin smell. As a result, it’s important to find a balance between both extremes.

How To Fix

Actively monitor the amount of organic matter you put in your compost. 1lb (0.45kg) of worms will eat about 0.28 lbs (0.14 kg) of food on average.

While worms have no problems with rotting food, they thrive best with fresh food waste. If you feed them a continuous supply of mold-filled, rotting food, they could refuse to eat it.

Mix fresh waste with rotting waste, and your worms should be fine. If there are any old, uneaten food scraps, it’s best to remove them when you see them.

Should You Put Worms In Your Compost?

As mentioned earlier, worms are decomposers. These small creatures help to break down organic matter in the compost, supplying your soil with much-needed nutrients such as Nitrogen, Phosphorus, and Potassium.

Together with other macro-organisms like mites, snails, beetles, and ants, they tear and chew organic matter, breaking them down into smaller pieces. This breakdown makes the decomposition process faster.

Unsurprisingly, worms are one of the most common decomposers in any garden. 

How Worms Help Your Compost

Here are some ways worms help your compost and why you should add them:

  • Worms break up debris
  • Worms castings are good for the soil
  • Worms naturally aerate your compost

Worms Break Up Debris

Worms are great at breaking up large chunks of organic matter into much smaller pieces. Although these chunks would break down regardless, breaking them up speeds up decomposition since it makes it easier for microbes to work.

They Leave Worm Castings Behind

After decomposing, worms tend to leave waste (worm castings) behind. These castings are essentially worm manure and help to enrich the soil with much-needed nutrients further. They also improve the soil’s ability to drain water.

Worm castings generate a lot of phosphorus, protein, nitrogen, magnesium, potassium, and potash.

Also, worm castings contain enzymes that break up the bonds in these nutrients, making them more accessible to your plants.

However, note that you shouldn’t keep your compost for a long time as the nutrients start to disappear after some time. Ideally, your compost should be less than a year old. I go into much more detail about compost aging and nutrients in another guide: Does Old Compost Lose Its Nutrients?

Worms Naturally Aerate Your Compost

When it comes to aeration, not many decomposers can do it the way worms can. As worms move through the soil in search of shelter and food, they leave a hollow trail behind them. 

This trail creates air pockets which make it easier for microbes and other decomposers to move through the soil and convert organic matter into compost.

Best Worm for Worm Compost

The best worm to use in your compost is a red wiggler or Eisenia fetida. These worms have reddish-brown bodies with yellow tails. 

When taken care of properly, they thrive in rotting organic matter and are extremely active. Their life span ranges from one to three years.


Unfortunately, some death is inevitable since turning your compost from time to time is vital for proper decomposition. That said, worm death is usually minimal, especially if you go the manual route when turning your compost.

It’s important to maintain a healthy worm population in your worm compost. These decomposers shred debris, aerate your compost and soil, and leave behind nutrient-packed castings. 

Asides from being turned over, they can also die from extreme temperatures, suffocation from compacted compost, and inappropriate moisture levels, so it’s important to keep an eye on these factors.

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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