How to Make a Cheap In-Ground Worm Composter in Time for Spring – Just Add Worms!
A lush spring garden starts with this easy (and budget-friendly) weekend project. Here’s how to make a worm composting tower using unwanted scraps and a handful of worms
Composting is a fantastic way to recycle kitchen scraps as life-saving nutrients that can nourish and sustain your garden beds and containers. Making this compost yourself can be simple, easy, and incredibly inexpensive, if you know what you're doing. You don’t necessarily need a fancy motorized tumbler or even a lot of space to make it happen. A quick and budget-friendly solution is to make your own in-ground worm composting tower, a vertical composting system that works right where your plants need it most.
Also known as a worm tower, this composting system is reassuringly straightforward for the eco-conscious gardener on a budget. Because it involves repurposing basic household items and unwanted materials, the costs are negligible – and the only real outlay is for the worms themselves. It’s a sustainable cycle that turns your morning coffee grounds and vegetable peels into a powerhouse of nutrients you can pay forward into your backyard, keeping waste out of landfills and money in your pocket.
Getting started now is the perfect way to prep for the upcoming season. While the rest of the garden is just starting to wake up, your underground crew of red wigglers can be hard at work. By the time you’re ready to tuck your spring seedlings into the earth, your tower will have already begun enriching some black gold that you can use to give your young plants a head start. Here’s how to make and maintain a budget-friendly, garden-friendly worm composting bin.
Why Try Worm Composting?
Worm composting (aka vermicomposting) harnesses the natural digestive power of worms as they break down organic material. Any sort of composting is essentially a win for sustainably minded gardeners, but a vermicomposting bin offers a fast-track to fertility. Because the worms do the heavy lifting of shredding and digesting, you can often see results in as little as 8 weeks, much faster than a cold-compost pile.
A worm tower is a great space-saver. This worm compost bin project uses the trench method, so doesn’t take up loads of precious space. It is well-suited for urban gardeners with more kitchen scraps than yard waste. Since the worms live and eat underground, these systems are naturally insulated and, when managed correctly, produce zero foul odors.
The real magic, however, lies in the worm castings. This is a polite term for worm poop. These castings are a lot more nutrient-dense than standard compost, packed with beneficial microbes and minerals that are immediately bioavailable to plants. And this particular project is incredibly easy on your pockets.
Your only outlay for this project will be the composting worms. You need to invest in composting-specific worms like red wigglers, rather than common earthworms. You should be able to find these online for $20-25. You can buy NaturesGoodGuys Red Wigglers from Amazon in tubs of 300 worms, ready and wiggling to do your composting bidding!
How to Make a Worm Tower
The most common DIY route for your worm bin composter involves a 5-gallon plastic bucket or a length of 4-to-6-inch (10-15 cm) wide PVC pipe. To prep your tower, drill a series of holes (approximately half an inch wide) around the sides of the lower two-thirds of the container. If you are using a bucket, drill several holes in the bottom as well, to allow the worms to move freely between the tower and your garden soil.
A pipe option is especially handy because it allows for deep insertion into the soil. The holes act a bit like worm doors. They allow the worms to exit the tower, deposit their nutrient-rich castings directly into the surrounding garden soil, and return to the tower to eat. This creates a radius of high soil fertility around the tower, and all without you having to move a single shovel of dirt.
The surrounding earth acts as a natural insulator, keeping your worms cool in the summer and warm in the winter. If you were to leave a plastic bucket sitting on bricks in the sun, by comparison, you would risk cooking your worm colony. This in-ground DIY method is far better for your worms (and for spring soil fertility).
Where to Place Your Worm Tower
The right worm composter location is everything when it comes to keeping worms happy. Choose a spot that is primarily shady. The tower should also be near established roots. Ideally, place your tower in a perennial bed, or near heavy feeders like tomatoes or squash. Worms will migrate out of the holes to aerate the soil and distribute nutrients directly to the roots of favorite plants. Just ensure it isn't in a high-traffic area where you might trip over the lid while weeding.
Dig a hole deep enough so the tower sits firmly in the earth with the top 3-5 inches (8-13 cm) and the lid above the soil line. This prevents rainwater flooding the unit while keeping the entry point accessible for you.
Adding Food and Bedding
Once your tower is in the ground, it’s time to make it cozy. Start with a layer of bedding. You don’t need to spend a dime here: shredded paper, corrugated cardboard, or empty egg cartons work perfectly. Soak your compost browns in a bucket of water first, wring them out until they feel like a damp sponge, and toss them in. If you have leftover coconut coir or fallen brown leaves, those make excellent additions.
Add your stars, the red wigglers (Eisenia fetida). Unlike common earthworms, these guys are surface dwellers that love living in the high-density organic matter contained in your worm tower. Add your first handful of kitchen scraps – think apple cores, carrot tops, and used coffee grounds (make sure they are used). A few inches is fine.
The All-Important Lid
Don’t forget to add a lid. This serves several purposes. It keeps the internal environment dark (which worms love), it keeps pests out, it retains moisture inside the tower, and it prevents your tower from pooling in a rainstorm. If you are using a 5-gallon bucket, the easiest lid is the one that came with it. If you are using a PVC pipe, look for a matching PVC cap at a hardware store, though those will cost extra.
For a zero-cost DIY lid, get creative with whatever is in your garage. Maybe try an old terracotta pot saucer turned upside down, a heavy flat stone, or a scrap piece of pressure-treated wood weighted down with a brick. Avoid using thin plastic wrap or flimsy cardboard, as these will degrade quickly.
Maintaining Your Tower
Maintenance is a breeze – it’s all about maintaining food for worms, and keeping things clean. Just add new scraps once the previous batch has been mostly consumed. If the tower starts to smell sour, you may be overfeeding or the contents may be too wet. Simply add more dry shredded paper to balance the moisture. In summer, give the tower a quick spritz with the garden hose if the bedding feels dry.
A good tip is that each time you add more kitchen scraps, it’s good to layer them with some of the bedding material. If you find that there are particular types of scraps not getting composted, it probably means the worms aren’t eating them. Remove these items and avoid adding them in the future.
To harvest compost, either just let the worms do the harvesting for you as they carry nutrients into the garden soil. Alternatively, if you want to use the concentrated compost elsewhere, stop feeding the tower for a couple of weeks. Then, place fresh food at the very top. The worms will migrate upward, allowing you to scoop out the rich, finished castings from the bottom and middle sections to use elsewhere.
Vermicomposting FAQ
Can I use regular earthworms?
It’s best not to use worms from your yard. Standard earthworms are deep-burrowers that need to move vertically through many feet of soil. Instead, deploy red wigglers. These are epigeic worms, meaning they naturally live in leaf litter and compost. They are much happier in the confined, food-rich environment of a tower.
What happens to the tower in winter?
In most climates, the worms should survive just fine, as they move below the frost line in the soil. If you live in an extremely cold region, you can keep them protected by mulching heavily over the top of the tower ,or temporarily moving a portable bin into a garage or basement.
Will my worm tower attract pests?
As long as you have a secure, tight-fitting lid and you avoid adding meat, dairy, or oily foods, pests are not likely to be an issue. Because the food is contained within a buried structure, the scent is significantly masked compared to an open compost pile. In many respects, an in-ground composter is one of the best pest-free options.
Budget Worm Composters
Our worm project is great for a cheap sustainable win, but if you’re not confident with a drill, don’t want to make holes in your spare bucket, or can’t find a spare bit of PVC pipe, these worm composting solutions are reasonably priced and offer great features for different needs:
Great for smaller yards and compact corners, this Vego option has a similar style to our DIY project and is easy to maintain and harvest.
This is a similarly affordable worm bin with different levels, including a raised bottom level that allows you to collect liquid worm tea (fertilizer).
Highly ranked brand that has simplified a sophisticated model into an easy-to-use worm tower for bulkier composting needs with excellent drainage.
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