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Why Are My Red Wigglers So Small? Causes & Solutions

Why Are My Red Wigglers So Small? Causes & Solutions

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Paul Brown

Red wigglers are literally a product of their environment. Everything they do, where they go, what they eat, is all directly related to their immediate habitat. Even the size of red wigglers is contingent upon their surroundings. Whether or not they’re big or small, depends on what’s going on in their small worlds.

So, why are your Red wigglers so small? If red wigglers are undersized, it is directly related to their environment. Causes of a red wiggler’s small size include overcrowding or not enough moisture or food. In fact, worms’ bodies are comprised mostly of water, so dehydration will cause them to shrink.

Worms, including red wigglers, are constantly searching for water. They know that it’s an important part of life – and the key to their very existence. We’re going to take a look at why your worms might be undersized, how to tell if they aren’t developing as they should, and how to maintain a healthy squad of red wigglers.

What Specifically Causes Smaller Red Wigglers


Too many cooks in the kitchen – or, too many worms in the bin. This is a common but easily fixed problem in a worm farm. Red wigglers are unable to get the proper nutrition and water if there are too many mouths to feed. When they are competing for limited resources, some will inevitably go without. Those worms will become lethargic and even slower to grab their fair share of food next time around. Whether or not it’s too many red wigglers or rodents that are coming in and stealing food, some worms are going without and they will not grow as they should.

If you’re noticing that your worms are smaller, and on top of that, you’re finding escapees, then overcrowding is most likely to blame. Luckily, this isn’t a terrible problem to have. It’s easy to fix and it means you’re a really good worm breeder.

How to Fix it

To solve the problem of overcrowding, you can simply take that single bed and make it into two. Split the worm bed by taking half of it and moving it to a separate location. It should be far enough away that it would be inconvenient for the new worm home residents to move out and rejoin the others. It’s a good idea to put the smaller ones together so that they can have room to grow and compete fairly for food against others their size.

Not Enough Moisture

As we already discussed, worms need water. Without water, they will literally shrivel up and die. If your worms are on the smaller side and looking a little dry and crusty, your worm population is dehydrating.

How to Fix it

This one’s an easy fix. And there’s a couple of options.

First, you can add a layer of damp, shredded paper compost to the top of your bin. Simply shred these and spray them with water. Then, sprinkle them over the top of your worm bin.

If you don’t want to shred all of this at home and you have children, tearing paper and cutting cardboard are both really great fine motor activities. Let the kiddos get involved too, make it a family affair. Bonus Tip: Consider moving those small worms into a see-through worm farm made for kids and let them experience the wonder of vermicomposting!

The second option is to keep a spray bottle around and to mist the vermicompost pile. Worms will regulate the moisture on their own, as they redistribute it through the composting process. But, in excessively dry weather or less humid climates, this is a little bit of an uphill battle. You can help the worms by giving them a spritz of water here and there.

Remember that balance is crucial. Just as not having enough water can cause your worms to shrink and dehydrate, having too much pooling water in your bin can result in your worms drowning. You want your bin to be damp, not saturated.

Not Enough Food

Worms are not exactly the best at hunting and gathering. They’re going to just eat whatever the sensory cells in the mouths guide them to eat. They will be turned off if the food is excessively moldy or rotten but for the most part, they will take advantage of what’s available. So, your red wigglers are relying on you to give them the healthiest worm diet. Without proper nutrition, the worms will never reach their full size.

How to Fix it 

Unless you’re preparing your worms a special diet such as ensuring a vegan-compliant fertilizer source for your garden, you’re more than likely giving them cast-offs from your own food prep that would otherwise be thrown out. So, to change your worm diet, you may have to change your own. Or, just be more cognizant of throwing your healthy scraps to the worms.

If you’re already eating lots of fruits and vegetables and whole grains, remember to toss those rinds and biodegradable peels into the worm bed. Here are a few things that are healthy and yummy, so your red wigglers will be well-fed:

It’s important to maintain a mixture of “greens” and “browns”. The “greens” consist of anything fresh, water-rich, and a source of nitrogen. Naturally, anything you add that’s brown is considered a “brown” or carbon-rich. To ensure you’re doing your part to keep your Red wigglers healthy, not going too heavy on either side is your best bet.

I’ve found that having more browns works best for my bin. A little extra cardboard or shredded paper helps to hold in moisture and at the same time soak up excess fluids. So, your mileage may vary. Test and monitor until you find the balance that works best for you. Click here to read my guide on how long red wigglers can go without food.

Another important element to making sure your red wigglers are getting the proper nutrition is to not bury any of their food too deep. When you add foods to your worm bin or compost pile, make sure that it’s not falling way down in a crack or crevice somewhere that your worms won’t be able to get to it. A general rule of thumb is to bury scaps 1 inch under the top layer of bedding.

Also, your compost bin or worm farm shouldn’t be too deep (source). This will help prevent any scraps or snacks for reaching places that are not accessible. Keeping all of the nutrition towards the top is important since red wigglers do not like to dive too deep for their food. They prefer to stay in the top six inches of their bin, to be specific.

How to Tell if Your Red wigglers Are Undersized

Small red wigglers can be a sign of overcrowding, lack of food, or lack of moisture.

Red wigglers are different than other worms for lots of reasons, but size is definitely one of them. It’s one of the main characteristics that makes it possible to distinguish what kind of worm it is, aside from color.

Red wigglers are usually smaller than earthworms but the biggest ones can grow to be as long as six inches. Although a red wiggler is no nightcrawler, it’s still a decent size. However, the average Red wigglers are between three and four inches, which is more likely.

However, if most of your red wigglers aren’t reaching their size potential, they’re undersized. If you’re noticing that the majority of your red wigglers are around an inch, or just under two inches, then they’re too small. If this is the case, one or more of the above reasons is probably the culprit.

How to Keep Your Worm Farm Healthy

Keeping your worm fam happy and healthy is one way to make sure they’re growing and developing as they should be. If your worms are the ideal size, they’re able to do their job efficiently and keep composting.

The key to doing this is to create a habitat that allows them to roam and eat as they choose. This video demonstrates just how simple it is to create a DIY worm bin.

How to Make a Worm Bin - Quick, Simple and Inexpensive

The rest is fairly easy and doesn’t require a lot of upkeep, other than feeding them and ensuring adequate – but not excessive – moisture.

Another fantastic bonus that works to your favor in keeping the worm population healthy is that they clean their own homes. They live in soil, so it’s not like it’s super clean to begin with. But they do compost and add all kinds of nutrients to their pile, so they’re kind of like their own little maintenance crews.


Red wigglers are hard-working little critters. As long as you’re keeping them hydrated and undercrowded and feeding them the right foods, they’ll do the rest of the work.

Keeping them healthy is fairly simple, as long as they’re getting the nutrition they need. They can turn your kitchen scraps into nutrient-rich fertilization for house plants, gardens, flower beds, or lawn. And vermicompost offers many advantages over other natural fertilizers such as manure. It all comes down to keeping the environment in balance and ensuring that the worms have what they need in adequate amounts. When you do this, your red wigglers can grow to the appropriate size.