A worm composter is a tool that uses worms to break down food scraps as well as other organic material to create a valuable soil called vermicompost. Not only does recycling household food scraps keep waste out of landfills, it also delivers beneficial nutrients to your garden.
If you’re an avid gardener, it’s likely you’re familiar with garden composters, but vermicomposting may be a new concept for you. Worm composting utilizes enclosed containers that allow the worms to break down waste, and many of these products can be used indoors or outdoors.
There are several different types of worm composters (also called vermicomposters) to choose from ranging in size, cost, style, and materials, and this vast selection can be overwhelming— especially for those who are new to the concept. It can also be difficult to decipher what brands are truly eco-friendly compared to companies that are greenwashing.
We understand how frustrating the research process can be, but we’re here to help so you can make an informed decision before you buy. Here, we’ve broken down our research on the top-rated worm composters so you can choose the right one for your home and garden needs.
- BEST OVERALL: Worm Factory 360
- BEST RUNNER-UP: Maze Worm Farm
- BEST BANG FOR THE BUCK: The Essential Living Composter
- BEST OUTDOOR: Subpod Mini Compost System
- BEST SMALL: Bio Vessel Eco Living
What to Look For When Choosing the Best Worm Composters
There are many things to consider when buying a worm composter, including the materials, where it will be used, design, and the amount of worms you’ll need for your household size.
Indoor or Outdoor Use
Before you purchase your worm composter, you’ll need to decide where you’re going to keep it in the home. Would you prefer an indoor or outdoor composter? Both have their advantages and disadvantages.
Outdoor composters tend to be larger and can process more food waste, whereas indoor composters are more compact, but are perfect for city dwellers and those with limited space. In addition to household size considerations, outdoor composting presents challenges during the colder months, while indoor composting allows the unit to maintain ideal temperatures year-round.
Style and Design
There are four main types of worm composters: stackables, beds, flow-through units, and bins (with different variations of each). The two most popular types are stackables and bins, as they’re great for beginners and easier to maintain. Worm beds are typically constructed for outdoor use, while flow-through composters are designed so that food matter and worms remain at the top of the unit, and worm castings are collected at the bottom. Whatever your preference, an effective worm composter has to meet the basic needs of the worms: air, food, moisture, warmth, and darkness.
Look for composters that are made from sturdy and durable materials. Most worm composters are made from plastic, but if you can, try to find one that is made from recycled plastics (such as r-HDPE or r-PP). Recycled plastics use approximately 66 percent less energy than virgin plastics, and can still be recycled (up to three times) at the end of the product’s life. If possible, search for pre-owned or refurbished composters before buying new.
It’s important to consider what type of worms you’ll use in the composter. The most highly recommended types for worm composters are red wigglers (Eisenia fetida) and redworms (Lumbricus rubellus). These worms prefer the composting environment over plain soil. If you’re new to composting, you can also check out our other guides like our complete list of the best compost bins and our in-depth reviews of the best compost tumblers.
After extensive research into the best overall worm composters, the Worm Factory 360 came up top again and again. Worm Factory is a well respected and renowned company within the permaculture world.
This particular model has a standard four trays that can be expanded up to eight, offering the largest volume of any other worm composters that we found. Despite having such a large volume, it only has an 18 by 18-inch footprint, so it fits well into small spaces. The Worm Factory 360 is perfect for those residing in smaller households, and can be used indoors or outdoors.
This bin is constructed from recycled HDPE (high-density polyethylene) plastic that’s incredibly durable, and with the correct care, should last for many years. Although products made using HDPE are not biodegradable, they can be recycled at certain facilities. When recycled, it’s commonly made into rope, toys, recycling bins, or trash cans. If you no longer require your worm composter, always try to re-home it before sending it off for recycling.
The Worm Factory 360 does require regular maintenance to avoid clogging, but the process takes less than 15 minutes per week.
- Material: HDPE recycled plastic
- Dimensions: 17.95 by 17.95 by 14.95 inches
- Weight: 11 pounds
- Capacity: 1.5 cubic feet
- Large volume composter that’s made in the U.S.
- Lid converts to a handy stand
- Digital instruction manual
- Built-in spigot for drawing excess fluid
- Suitable for indoor or outdoor use
- The trays can be cumbersome to move
- Requires regular maintenance to avoid clogging
Get the Worm Factory composter on Amazon.
Check for a refurbished Worm Factory on Ebay.
Constructed with mostly recycled polypropylene (the black plastic portions) and designed and manufactured in Australia, the Maze Worm Farm is ideal for those who are new to worm composting or have limited outside space. The worms inside the Maze Worm Farm can digest up to 8.8 pounds of kitchen waste per week.
As the entire unit only weighs 6 pounds, it’s easy to move around. You can also purchase additional legs to make it higher if you’re struggling to bend down to collect the worm leachate (excess liquid run off).
The bin contains two working trays that can be rotated and are stacked vertically for optimal aeration, making it a great home for the worms. The “worm saver” feature stops the worms from falling out of the bottom, and makes scraping out the worm castings an easy job.
Unlike some others, the Maze Worm Farm composter only has two trays (potentially limiting growth), so it may not be a good choice for those who want to expand their worm colony.
- Material: Made with mostly recycled polypropylene
- Dimensions: 15.1 by 15.1 by 11 inches
- Weight: 7.7 pounds
- Capacity: 6 pounds
- Made with mostly recycled material
- Small and manageable
- Easy to assemble
- Two trays can limit growth
- The green parts of the composter are made with virgin polypropylene
Get the Maze worm composter on Amazon.
With a fast-and-easy installation process and a budget-friendly price, the Essential Living Composter is a solid choice for beginners looking for an affordable way to get started with worm composting. The only other items you need to set up this bin are your worms and food scraps.
The black and gray versions of this durable bin are made with 100 percent recycled polypropylene (as is the plum version when available), however, the green option is only made from 10 to 50 percent recycled material. In general, polypropylene is more environmentally friendly when compared with other plastics, as it’s recyclable and doesn’t release as many toxins. In addition, polypropylene breaks down after 20 to 30 years on average, compared to 500 years for other types of plastics.
The stackable-style composter comes complete with a water retention channel that runs along the outside of each tray and helps to control moisture. These channels gather the moisture and prevent the bedding from drying out around the edges.
One drawback to this particular composter is the worms can get stuck in the bottom tray. To try and combat this, it’s advised to line the bottom tray and frequently drain the leachate. This should stop the worms from getting stuck and drowning in the leachate.
You’re also limited on how much you can expand this bin. It was designed to provide enough composting potential for an average apartment dweller. However, you can’t add an extra third or fourth tray because the small legs won’t hold the weight.
- Comes in four different color options
- Made with mostly recycled plastic
- Ideal for indoor use
- Worms can get stuck in the base tray
- Limited expansion potential
- Recycled material is not always available for certain colors
- Material: Recycled polypropylene
- Dimensions: 15 by 15 by 22 inches
- Weight: 10 pounds
- Capacity: 6 gallons
Get the Essential Living composter on Amazon.
The Subpod Mini is not a traditional worm farm, but a compact aerobic system and vermicomposter hybrid that sits under the ground, so it takes up very little space and helps with pest and odor control. Due to its subterranean positioning, the unit is naturally insulated to create optimal composting conditions for the worms to go to work.
This mini unit can compost up to 22 pounds of food waste per week, and is suitable for households of one to four people. Installation instructions are easy to follow, and regular maintenance takes just a few minutes per week. It’s worth noting that the lid is very heavy, potentially making it hard to lift. Unlike traditional worm farms, this cannot be used indoors.
It’s estimated that every year, a Subpod unit diverts more than 1,600 pounds of food waste from landfills and over 600 pounds of CO2 from the atmosphere.
- Material: BPA-free, food-grade polypropylene
- Dimensions: 19.4 by 17.7 by 16.9 inches
- Weight: 16.27 pounds
- Capacity: 22 pounds
- Odor-free, aerobic system
- Pest proof
- Minimal maintenance
- Can take longer to set up than the suggested time
- Heavy lid
- Cannot be used indoors
- Made of virgin plastic (although it is recyclable)
Get the Subpod worm composter on Amazon.
This sleek, countertop worm composter is made from 100 percent recycled HDPE plastic. Its compact size makes it perfect for city dwellers or small household sizes. Or, if you lack space or are new to worm composting, this is the composter for you.
Biovessel was created after more than 20 months of experiments, biological research and observations on food decomposition.
Due to the small ecosystem of this composter, there is no odor emitted from the bin. The worms eat all of the rotting food prior to fermentation—before odors have a chance to develop. The unit has an observation window that makes it easy to check on progress. However, due to the small size of the main opening, one drawback of the composter is that it can be challenging to fit the food scraps inside. During use, be sure to secure the lid tightly so that the worms do not escape.
- Made from 100 percent recycled HDPE plastic and cork
- Compact, stylish design
- Easy to set up
- Great for beginners
- Limited capacity
- The hole for the food waste is very small
- Material: Recycled HDPE plastic and cork
- Dimensions: 17.7 by 8.7 by 6.5 inches
- Weight: 3.3 pounds
- Capacity: 7 liters
Get the Biovessel worm composter on Amazon.
The Worm Factory 360 is the perfect all-around worm composter for both beginners and people who are familiar with worm composting. It ticks all of the boxes when it comes to a good worm keeping setup, and unlike some other worm composters on the market, it’s made from recycled plastic. The Worm Factory 360 is extremely durable and should last for many years, but it can also be recycled at the end of its life. If you’re looking for something more compact with a smaller price tag, the Essential Living Composter is a great alternative and is also made from recycled plastic.
How We Chose the Best Worm Composters
Of the worm composters we researched, we considered the specifications of the products, including what the product was made from, if recycled materials were used, where it was made, if the unit could be easily recycled after use, and whether it was BPA-free.
We then evaluated the cost, customer ratings, past reviews and overall customer satisfaction of each worm composter. We reviewed 25 top-rated worm composters in total to bring you our comprehensive and unbiased selections.
All of our picks for the best worm composters are easily recyclable and/or made from mostly recycled plastics.
Q: How much do worm composters cost?
Worm composters vary in price depending on factors like size, the type of worm composter, the equipment the unit comes with, and where you buy it from. As a general guide, they can cost anywhere from $30 to $400.
Q: Is a worm farm better than a compost bin?
Traditional compost bins use microbes to break down organic matter, whereas worm composters use the worms themselves to do this job. The worms eat through the rotting scraps and excrete them to create worm castings (worm poop). These worm castings are full of nutrient-rich soil fertilizer that’s great for your garden. This process is a lot faster compared to other composting methods, especially when you have a lot of worms.
Q: How many worms will I need?
How many worms you need depends on two factors: how much food waste you regularly produce and the size of your worm bin.
You can calculate your weekly food waste either by weighing it, or estimating the amount per week. The worms on average will eat between 25 to 35 percent of their weight per day. These figures are from academia research, however, some others suggest they eat a much higher amount. Using this information, we can calculate that 1 pound of worms can eat on average 1.75 to 2.45 pounds of food waste per week.
Taking that into account, a good number of worms is 1 pound per the square footage of your chosen bin. For example, if your bin is 24 inches by 18 inches, the ideal amount for your bin would be 3 pounds of worms. You would need between 5.25 pounds and 7.35 pounds of food per week to keep them happy.
Q: Can worms eat banana peels?
Yes, worms, including red wigglers, can eat and enjoy banana peels as well as the flesh. Vermicomposting banana peels and the skins is a great, eco-friendly way to recycle banana waste. Just make sure to chop up the banana before putting it into your compost bin so that the worms can get to it before it goes sour. Other fruits that worms love include apples, watermelon, peaches, pears and apricots.
Q: How long does it take to compost using worms?
One of the main benefits of worm composting is it works quickly compared to other composting methods. The worms can convert most kitchen waste into compost within two weeks, and can also work throughout the winter, however, you may need to move your bin inside to reach the optimal temperature. In order to ensure the worms still work during the winter months, make sure to keep your worm bin between 55 and 80 degrees Fahrenheit.
Q: If I’m buying a new worm composter, what can I do with my existing one?
If you already have an existing worm composter but plan to buy a new one, you could donate your old one to a friend or family member so they can reuse it. If the worm composter is broken or no longer viable, try upcycling it. Finding new ways to use old products can be incredibly rewarding, and helps to keep items out of landfills. If upcycling isn’t your thing, try researching recycling programs in your area, donate it to a local charity, or send it to an organization that supports environmental causes.
Q: Is it better to buy a new worm composter or a renewed/reused one?
One of the main principles of sustainable living is to reuse already existing items wherever possible. The same applies for worm composters. If you can get one that has been pre-owned, that is always better than buying brand new. Before you use a pre-owned worm composter, make sure it’s completely clean, dry and free of any contaminants.