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Why Worm Bins Need Air Holes (It’s More Than Just Oxygen)


Worm bin air holes

Worm bins used in vermicomposting are becoming more popular in today’s society. It is essential to know the basics of vermicomposting before you decide to make your own. For instance, it is important to understand the life of an earthworm and how they breathe. This will tell you why worm bins need air holes. If your bin doesn’t have adequate air holes, your worms could die, and your vermicompost project will fail.

Why do worm bins need air holes? Worm bins need air holes to provide ventilation for the worms to breathe. Air holes also play a critical role in regulating moisture and temperature control inside the bin. Successful vermicomposting requires and understanding of this complex connection to prevent issues like odors and dying worms.

Aside from just making sure your worm bin has air holes, there are several things that you will also need to consider. For instance, how many holes are sufficient to keep your worms alive and what kinds of things aren’t good for your worms in the worm bin. This is important because putting the wrong items in your bin can cause it to have odors and those air holes can also allow unpleasant smells to be released.

Click here to see our top recommended worm bins

How Air Holes Effect The Basic Needs Of Compost Worms

Worm bins are also called vermicomposting bins, which is essentially composting with worms. It isn’t like having a regular old compost pile and compost worms are generally not the same worms you find under the soil in your yard.

There are precautions you must take because you will be caring for living creatures within your compost bin. It may seem like vermicomposting is more work than just building a compost pile because of caring for the worms, but worm bins actually don’t require a great deal of effort once you set them up and learn how to keep them in balance.

One advantage of vermicomposting is that the food gets broken down quicker with the help of worms. 

Like humans, worms do their best when their needs are met. Beyond water and oxygen, these needs are essentially food and shelter:

  • Suitable living conditions
  • Comfortable housing arrangements
  • Appropriate amounts of food

Suitable Living Conditions

In order for the living conditions in the worm box to be suitable for sustaining a long life for your worms, it will need to be properly ventilated. This can be accomplished by drilling a number of holes into the lid and upper walls of the worm bin when building one as a DIY project. If you buy one from the store, it will come with holes already pre-cut into the box. 

Worms need proper ventilation because, without it, they would die. They do not have lungs like humans do, but they breathe oxygen and diffuse carbon dioxide out through their skin. Without proper airflow in the worm bin, the worms will essentially get poisoned to death from the carbon dioxide that is excreted from their bodies. To make sure your bin is properly ventilated, you will need to make sure you create an adequate number of air holes in each side and in the lid. 

To keep the life within the worm bin sustainable for your worms, you will also need to make sure the moisture point doesn’t get too dry. Worms require their skin to always be wet with moisture; this allows for the proper diffusion of carbon dioxide to completely take place. If their skin dries out, they will suffocate and die. So the answer to this problem is to make sure that you keep the bedding of the bin damp to the touch. Don’t overdo it, however, as this can create other problems (more on that later).

Comfortable Housing Arrangements

Along with all the above-mentioned amenities, your worms will also require a somewhat temperature-controlled atmosphere. They are living things after all, and all living things require some form of temperature control. This is why it is highly recommended to keep your worm bin indoors. This is, in fact, one of the best methods of indoor composting.

Air holes actually help to control the temperatures inside your worm bin. Without air holes, heat would have no way to escape and the temperature-regulated air around it could not enter. Just like opening windows in your home on a spring day, air holes allows the temperature within the bin to regulate and not reach extremes.

Appropriate Amounts Of Food

Air holes help to regulate temperature and moisture levels effected by foods.

This is a key factor to consider because if you overfeed your worms, your worm bin will start to give off a rotten smell because your worms won’t be able to eat the food quick enough. On the other hand, if you underfeed your worms for too long, then they will eventually start to die. Once again, we come to the importance of maintaining balance.

A good rule of thumb is to remember that for every pound of worms you have, they can eat a half-pound to one pound of food each day.

If you are unsure of what to feed your worms, I have included a brief list below:

Food worms love:

  • Melon rinds
  • Non-citrus fruit
  • Squash
  • Dryer lint
  • Crushed eggshells
  • Paper towels
  • Pet hair
    • In small amounts
  • Teabags
  • Coffee filters

Food they can eat in small amounts:

  • Citrus fruits (affects pH of the bin so I recommend avoiding this)
  • Onions
  • Garlic
  • Bread

Off-limit foods for worms: 

  • Meat 
  • Dairy 
  • Oil
  • Cooked food

Red wiggler compost worms will eat slightly molded or rotting foods but remember that these can smell. Worms have extremely simple digestive systems and can’t handle a lot of the foods and spices that humans can eat. Also, their bedding usually includes shredded cardboard and paper and they’ll eat that too!

Air Holes Help Control Moisture

Another reason that air holes are so critical in a worm bin is that they help to regulate the moisture levels inside. Worms require moisture but too much can cause problems including pungent smells and your worms even trying to escape. Air holes allow for some of the excess moisture to be released and fresh, drier air to enter. You still need to make sure there is an efficient draining system for the bin in the bottom but air holes do play a part in this.

Remember also that the foods you add can significantly increase the amount of moisture in the bin. Melon, for example, is very water-rich. Air holes, along with proper bin drainage for excess liquid, help to keep moisture levels in check.

How Compost Worms Breathe

The breathing process of a worm is rather simple. As I have mentioned before, they do not have lungs, and they don’t have noses either. A worm takes its oxygen in through the moisture in its skin (another reason that moist bedding is so important). The air dissolves through the mucus of its skin, and as the fresh air is taken in, the oxygen is drawn into the worm’s circulatory system (source).

This is when the heart comes in. The heart pumped the oxygenated blood to the head, and the movements from the worm’s body keep the blood flowing to the back end of the body. Then the heart pumps the blood back forward again, and the process repeats. The carbon dioxide is then dissolved out of the blood and back through the skin.

This may bring up another curious point:

How Long Can Worms Go Without Oxygen?

The answer to this question varies from worm to worm. This is when the idea of survival of the fittest comes to mind. Some worms can last a little longer without oxygen than others, but regardless, once the oxygen supply has been cut off, the worm won’t be able to last much longer after that

As you can see, air holes necessary are a vital part of any worm bin. Worms are low maintenance creatures, but at the end of the day, they are still living beings that require certain essentials to survive. The above necessities might seem like a lot of work, but I’ve found that if you take the time to set up your worm bin properly in the beginning, it should mostly take care of itself after that. 

As your worms go to work consuming you will soon start reaping the benefits. The soil you will acquire from your worms will be filled with natural nutrients that will help your plants or even your lawn to thrive. Making sure your bin has air holes for ventilation, proper moisture, temperature control, and appropriate amounts of food is a small price to pay for what becomes essentially free organic fertilizer.

Where To Buy Composting Worms

The easiest way to buy composting worms is to just purchase them online and have them delivered right to your door. You can purchase live composting worms (link to Amazon) and build a simple DIY worm bin that’s ready to go by the time they arrive. If you are not into DIY projects, take a look at our recommended compost products page and you will find a vermicomposting bin available online that already has all of the necessary considerations like air holes and drainage built-in.

However you choose to take it on, vermicomposting is a relatively simple and hassle-free way to take advantage of your kitchen scraps and turn them into nutrient-rich fertilizer for your lawn, garden, and plants.

Paul Brown

Paul has a two-acre yard on red clay soil in Southeast Texas. He knows exactly what the challenges are to nurturing a thriving yard in difficult soil. He takes a practical approach to yard improvement and enjoys putting best practices and “golden rules of lawn care” to the test. Click here for Paul’s author page

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