How to Make a Worm-Composting Bin From Plastic Buckets

compost bucket with food scraps and worms

​The Spruce / Candace Madonna

Vermicomposting is the technical name for what has become known as worm composting—the process of using various species of earthworms to digest and convert organic material into useable garden compost. Traditional ready-made vermicomposting bins can be a convenient way to start turning your food scraps into compost for the garden, but there can be two problems with ready-made bins: Either they're too expensive or they're too large. Worm bins can cost upward of $100 or more in many retail outlets. While they do work well, most gardeners would rather spend their money on plants.

The space issue is maybe even more bothersome. Often, the most convenient place to store a worm bin is inside a kitchen cabinet. They're out of sight this way, and it's a convenient place to dump your veggie and fruit scraps. However, kitchen cabinet space is often at a premium and a large, tub-type bin takes up too much valuable space.

The solution to both the financial and space issues is to make your own worm bin. Plastic 5-gallon buckets, such as the kind you can buy from your local home center for a few dollars, fit the bill perfectly.

Working With Vermicomposting Bins

Vermicomposting bins are structured so that the worms will start out with bedding and food on one level. As that level gets digested and turned into vermicompost, you start adding food and bedding to the next level. The worms instinctively migrate up into that level, leaving behind finished vermicompost for you to use in your garden. You simply keep switching back and forth between the two buckets, emptying finished compost then adding fresh food and bedding as the worms break it down for you.

The third bucket forms the bottom of the stack and is used to catch any moisture created as a byproduct from the other two bins. You can harvest this "vermicompost tea" from the lowest bucket and use it to fertilize your plants.

Project Metrics

 Working Time  30 minutes (to make the system)
 Total Time  3 to 6 months (to produce finished compost)
 Material Cost  $40 to $50 (including purchased worms)

What You'll Need

Equipment/ Tools

  • Drill with 3/16- and 1/8-inch twist bits
  • Trowel

Materials

  • 3 Plastic buckets (5-gallon size is best)
  • 1 Bucket lid
  • Shredded newspaper or cardboard
  • 250 to 500 Red wiggler composting worms
materials for making your own composting bin from buckets
The Spruce / Candace Madonna

Instructions

  1. Drill Bottom Holes

    In two of the buckets, drill 3/16-inch holes in the bottom, about 1 inch apart. Do not drill holes in the third bucket.

    drilling holes in the bottom of a bucket
    ​The Spruce / Candace Madonna
  2. Drill Side Holes

    Drill a line of 1/8-inch holes through the lip of both buckets, near the top. These holes will provide airflow for your bins, so the contents don't get too wet.

    drilling holes near the top of a bucket
    ​The Spruce / Candace Madonna
  3. Prepare the Lid

    Drill a large number of 1/8-inch-diameter holes through the lid. This will provide added aeration that will help break down the contents quickly.

    drilling holes in the lid of a bucket
    ​The Spruce / Candace Madonna
  4. Assemble the Vermicomposting Bin

    Stack one of the bins that has holes in the bottom inside the bucket without holes. Add 3 to 4 inches of moistened shredded newspaper or cardboard to this bucket, then add the worms. You can also add some food scraps at this time.

    stacking buckets
    The Spruce / Candace Madonna 
  5. Cover the Bin

    Just put the lid on the bin and let the worms do their thing. Add food as often as you need to—whenever the contents have been mostly digested.

    putting the lid with holes on the bucket
    ​The Spruce / Candace Madonna
  6. Add the Third Bucket

    Once the contents of this layer have been partially digested by the worms, stack the next bucket with holes onto the bin, adding fresh bedding and food to the new bucket and placing the lid on top. The worms will start migrating up to the top bucket for fresh food and bedding.

    The time it takes for the worms to break down the contents of the bottom bucket will depend on the number of worms and the quantity and type of organic material you put inside, but it generally takes three to six months to create a full bucket of compost ready for garden use. This might seem like a long time, but it can be considerably faster than passive composting in an open compost bin.

    As the bottom bucket fills with liquid, this "compost tea" can be used to feed plants. Empty the "tea" often, as it can begin to smell if allowed to remain too long.

    stacking another bucket on top
    ​The Spruce / Candace Madonna 
  7. Harvest the Compost

    As soon as most of the worms migrate up into the upper bucket, the contents of the underlying bucket can be harvested. The vermicompost is a versatile material that makes a great food or soil amendment for virtually all plants.

    harvesting compost
    ​The Spruce / Candace Madonna
  8. Repeat the Process

    Keep repeating the process as the lower bucket gets full, is emptied of its compost, and is moved to the top of the stack. Once established, your vermicomposting system can handle virtually all the organic non-animal refuse your house produces.

    repeating the process
    ​The Spruce / Candace Madonna 

Tips for Vermicomposting

This is a very simple system, but there are some things to keep in mind:

  • Don't let the contents get too wet. If they do, there are a number of ways to fix a wet worm bin, such as adding more fresh bedding.
  • Don't let the contents dry out, either. This is death for worms. The contents of the bin should feel as moist as a wrung-out sponge.
  • It is a good idea to add a few handfuls of the original vermicompost to the new bucket as you stack it on top. This will introduce a few worms—and maybe eggs—to the new bin, as well as other beneficial microorganisms to help with the decomposition process.
  • Maintain several worm bins for maximum composting capacity. Line them up in your basement or mudroom, and you'll always be able to compost your kitchen scraps.
  • Avoid putting animal materials (meat, eggs, etc.) into a vermicomposting bin. While worms can and do break down animal wastes, it can take too long for the process to occur, allowing bacteria and other pathogens to flourish.