Whether you are a new gardener or a seasoned veteran, you’re likely already familiar with the concept of composting: allowing fruit and vegetable scraps and healthy plant debris to decompose and produce rich, organic material you can return to your soil.
Both compost tumblers and worm bins are great alternatives to an open compost pile, and you can use either one to produce high-quality compost. However, they will not meet every gardener’s needs, so consider their benefits and limitations before you invest.
Composting can require a good deal of maintenance. Fortunately, the right approach can reduce some of the challenges of composting while still providing nutrients for your garden.
What Are Compost Tumblers?
Compost can be managed in one of two ways: a freeform pile or some kind of container. Because compost piles can be smelly, unsightly, and attractive to pests, most gardeners use a bin of some kind.
Compost tumblers are different from other types of bins in that the storage drum is attached to a frame that keeps it off the ground. The frame design allows you to rotate, or “tumble” the drum to aerate the compost inside.
Generally, the drum of a compost tumbler is positioned horizontally or at a diagonal. Not only does this design keep the drum off the ground but it also makes tumbling much easier since the drum is already in a starting position.
Inside of most cylindrical compost tumblers are “baffles” similar to what you might find inside a dryer. The baffles stir up the compost as the drum rotates.
Compost tumblers that are available for sale range in size from small 15-gallon drums to very large 170-gallon drums. You can even make your own if you prefer the DIY route (source).
Tumbler bins are also easy to customize to meet your specific needs:
- You can add wheels or casters, or buy one with wheels, to allow for easy movement around your garden or patio.
- You can add a crank, or buy one with a crank, if that’s how you prefer to turn the drum.
- You can buy or build a tumbler with more than one bin to separate materials at different stages of decomposition.
- You can choose different colors, different materials, and different vent designs depending on your own preferences.
While compost tumblers are a great option for all types of gardeners, they work especially well for gardeners who have small yards or patio gardens. The smallest tumbler bins take up very little room while still holding several gallons’ worth of food and plant waste.
How Do Compost Tumblers Work?
There are two primary methods you can choose to use with a compost tumbler:
- Dump and tumble (cold process)
- Batch method (hot process)
The size of your compost tumbler will likely determine which method you use, but both are effective when done properly.
Dump and Tumble (Cold Process, Active Management)
The dump and tumble method is extremely convenient for home gardeners. Gardeners simply add organic waste (fruit and veggie scraps, lawn clippings, etc.) to the bin as it is available.
Once the organic waste is added, give the bin a few tumbles to mix the new with the old and walk away!
Opinions vary about how hard the bin should be tumbled and how often. As long as you follow the manufacturer’s guidelines, the rest is really up to you and what you find works best.
Depending on the season and temperature, complete decomposition may take anywhere from six to twelve months.
While this process is extremely simple and convenient, there are several steps gardeners should take to optimize the decomposition of materials.
- Tear, chop, or shred the waste before adding it to the bin. Smaller items will decompose more efficiently than larger ones.
- If the materials you want to add are dry (e.g. shredded paper), soak them in water first. You want the moisture level in the tumbler to be around 50%, comparable to a wrung-out sponge, at all times.
- Every time you add to your tumbler, sprinkle in some coarse material to add bulk. Twigs, pine needles and cones, and small sticks are good examples of bulking material. These increase the airflow in your bins and prevent wet items from becoming too compact.
- Every three months or so, sift small amounts of your compost. The material that is done decomposing will resemble coffee grounds. Unfinished material can be returned to the bin to finish decomposing (source).
Batch Method (Hot Process)
This method will work best for gardeners who use 70 to 170-gallon tumbler bins. It is referred to as a “hot process” because the microbes in the compost will release some heat; the heat does not come from the sun.
As the name suggests, compostable materials are added all in one batch at one time. Because of the heat released during decomposition–optimally up to 150℉–it will take only three to six months to have finished compost (source).
You can try this method in a smaller tumbler bin, but the smaller sizes simply can’t maintain the same level of heat that larger ones can.
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Here is how the batch method works:
- Fill your bin about three-quarters full.
- For best results, aim for a 2:1 ratio of “brown” (straw, dry leaves, dry grass clippings, paper, etc.) to “green” (veggie scraps, coffee grounds, green plant waste, etc.). This will provide the right balance of carbon and nitrogen during the decomposing process.
- Approximately once a week, give your bin a tumble and check the moisture level. Similar to the dump-and-tumble method described above, your moisture level should be around 50%.
- After three months, you can begin sifting out finished compost (source).
Common Problems and How to Solve Them
Problem: Too much moisture in the bin
Solution: If you have any wet clumps of material, break them up. Add some dry bulking material and gently tumble the bin. Be sure to continue to add bulking materials every time you add organic waste to your bin.
Problem: Too little moisture in the bin
Solution: Without flooding your bin, sprinkle water into it. Remember the contents of your tumbler should be approximately as moist as a sponge that’s been wrung out. You can also soak dry materials before adding them.
Problem: The bin is full, but the compost isn’t finished.
Solution: Start a separate bin or pile if you have the space. If not, continue to check your bin’s moisture level and allow decomposition to happen naturally. Harvest your finished compost as soon as it’s ready.
Problem: The bin has become too heavy to turn.
Solution: First and foremost, avoid injuring yourself! As long as the moisture level remains around 50%, your bin’s contents will keep decomposing whether you tumble your bin or not. Keep an eye on the moisture level, harvest what you can, and be patient.
Problem: Decomposition is taking too long.
Solution: New composters are often frustrated by the seeming lack of progress in their bins, but unfortunately, even hot process composting simply takes a long time. Be prepared to wait several months before harvesting usable compost (source).
What Are the Advantages of Compost Tumblers?
- Because compost tumblers don’t sit on the ground, they are fairly animal-proof.
- They are available in a variety of sizes and shapes with convenient add-ons like wheels and cranks.
- Gardeners with the right tools and know-how can build their own.
- They are perfect for gardeners who have limited space or who are unlikely to fill a large container quickly.
- They are a good option for gardeners whose physical limitations prevent them from being able to turn and harvest compost from a large pile.
What Are the Disadvantages of Compost Tumblers?
- They are not all created equally nor created for all climates. Consult your local Extension agent or garden center for recommendations.
- Compost tumblers may be animal-proof, but they are not insect-proof (source).
What Are Worm Bins?
Worm composting, also known as vermicomposting, is a composting method that uses worms to break down food scraps into usable compost.
The basic idea of a worm bin is similar to the idea behind other compost bins: organic waste is added to the bin and converted into nutrient-dense compost for your soil. Worms live in the bin and aid the decomposing process by eating the food scraps you add to the bin, digesting them, and recasting them.
Once the recast material in the bin reaches the consistency of coffee grounds or cake crumbs, it’s ready to harvest and use.
Worm bins may seem complicated because they rely on the health and reproduction of the worm population in order to work. However, worm bins are actually very simple structures involving one or more chambers where the worms live, eat, and create compost.
Unlike compost tumblers or other compost bins, worm bins are designed more for indoor storage. Worms live near the surface of the soil, so bins can’t be more than one foot deep if the worms are to remain healthy.
While you can buy manufactured worm bins, they are surprisingly easy–and much cheaper!–to make. If you have a couple of opaque plastic storage tubs, a drill, and some newspaper, you can make your own worm bin in minutes. The Washington State University Extension provides these very simple instructions for building your own worm bin.
Whether you choose to buy or make your worm bin, there is a simple ratio to determine the right size: for each pound of food waste, you’ll need one pound of worms (500 to 1,000) and one cubic foot of space in your bin. Maintaining this balance will ensure that the worms have enough food and oxygen to grow and reproduce (source).
It is also important to note that there are just seven species of worms that can be used for vermicomposting. The species most commonly used in the United States is the red wiggler (Eisenia fetida). You can purchase red wigglers online (link to Amazon).
It is also important to be careful about what kinds of food scraps you add to your worm bin. Since they are kept indoors, for the most part, you may notice unpleasant smells from veggies like onions and broccoli. Citrus peels are too high in acid, so they may attract fruit flies before they decompose. Make sure you understand which foods not to put in a worm bin.
Furthermore, grass clippings and other lawn waste cannot be added to your worm bin. As they decompose, they produce too much heat, so they aren’t suitable for the worms’ habitat.
As with any form of composting, cooked foods, oils, dairy products, and meat products are not suitable for your worm bin (source).
While there is potential for pests and bad odors, if you properly maintain your worm bin, these won’t be problems at all.
How Do Worm Bins Work?
Setting Up Your Worm Bin
Whether you buy or build your own, make sure your worm bin has adequate holes for drainage and airflow.
Worms are sensitive to light, so if the bin isn’t opaque, paint it a dark color. Choose a location for your bin that is out of direct sunlight. Worms are also sensitive to temperatures below 55℉ and above 77℉, so bear that in mind as well.
In order to succeed in creating compost, your worms will need:
- Newspaper, plain white printer paper, or cardboard to act as bedding
- Grit, such as garden soil
- Fruit and vegetable scraps
Newsprint, plain paper, and cardboard are all part of a red wiggler’s balanced diet. In addition to providing worms with essential nutrients, these bedding ingredients are good carriers for moisture and help maintain airflow in the bin.
Many experts recommend shredding the newspaper or printer paper into one-inch wide strips and cutting the cardboard into small pieces. Soak these in water and wring them out. You want them to be moist, but not soggy.
This will form the primary home environment for your worms. As you put your bedding in the bin, keep it “fluffy,” instead of packed down, to maintain good airflow. This layer of bedding should fill your bin about three-quarters full (source).
Worms are toothless, so they rely on soil or other types of grit to help them break down food. Before adding worms to your bedding, add about one good handful (roughly ½ cup) of soil.
Other materials make good grit as well: crushed eggshells, vermiculite, non-medicated crushed chick starter, and sand.
Your worms will need a handful of fresh grit approximately every two months (source).
There are three different approaches you can take when adding your first food scraps to your bin:
- Allow the scraps and bedding to decompose together for a few days before putting your worms in the bin.
- Add the worms to the fresh bedding and grit and let them settle into their new home for a few days before adding scraps.
- Put worms and fresh food scraps into the bin at the same time.
Regardless of your approach, it’s best to not overwhelm your worms with food scraps right away. Feed them one-quarter to one-half the amount you plan to feed them per week and gradually increase that amount as they acclimate (source).
Once you’ve added your worms, you’ll want to keep a sheet of newsprint or a piece of cardboard over the top of the worms and their new habitat. This helps regulate moisture levels, keeps odors from filtering out, and keeps flies at bay (source).
Maintaining Your Worm Bin
Maintaining your bin is easy, since the worms are doing all the hard work!
Feed your worms and fluff their bedding about once a week. If the bedding feels dry, spray it with water; if it feels soggy, mix in some dry paper strips. Add fresh bedding periodically and replace the upper sheet of paper or cardboard as necessary.
There are several ways to harvest compost, and the right way will likely depend on the type of bin system you use.
One easy way is called the scoop-and-return method:
- Remove the top layers of the bin–the fresh bedding, food, and worms–and place them in another bin or box.
- Scoop out the bottom layer to use as compost.
- Return the bedding, food, and worms to the bin and add fresh bedding on top (source).
Common Problems and How to Solve Them
Problem: The worms are dying or escaping.
Solution: Start by harvesting whatever you can from your bin. Add fresh bedding, making sure the moisture level in your bin is approximately 50%. For more information, see Why Are My Composting Worms Trying To Escape?
Problem: The bin has an unpleasant odor.
Solution: Add fresh bedding but no new food for two weeks. You may also want to drill more holes to improve ventilation and keep your bin a little drier.
The type of food scraps may also be an issue here. Avoid scraps that tend to be stinky on their own (onions and broccoli) and never add oily foods, meat, or dairy products. Dig deeper into this problem with our in-depth article Why Does My Worm Bin Smell? Causes and Troubleshooting Steps
Problem: There are fruit flies in the bin.
Solution: Make sure your food scraps are covered by bedding and that the bedding is covered by a full sheet of newsprint or cardboard. Fruit flies are attracted to exposed food, so keep the scraps buried (source).
What Are the Advantages of Worm Bins?
- They can be kept indoors.
- They are small and compact.
- They are easy to build.
- They produce usable compost in about half the time of other composting methods.
- When properly maintained, they aren’t as odorous as other composting methods.
What Are the Disadvantages of Worm Bins?
- Not all compostable materials are suitable for worm bins.
- The methods are easy, but they still require more maintenance than compost piles or bins.
Compost tumblers and worm bins are both excellent choices for gardeners who want to use sustainable methods to return nutrients to the soil. However, they will not meet every gardener’s needs equally.
Before you invest, carefully consider the types of materials you want to compost, how much space you have, and how much work you want to do to maintain your composting system. The answers to these questions will help you decide which method is right for you.