How to Build Your Own Vermicompost System

What is vermicomposting?

Vermicomposting is a type of composting in which earthworms facilitate the breakdown of organic matter. Through this process food waste is transformed into the end product, worm castings. This method has all the benefits of traditional composting, which relies primarily on microbes, but also additional assets such as faster breakdown time and more nutrient-rich product.  Worm castings are considered highly valuable, and you could even make money selling them!

I’ve kept worms for a while, but haven’t started what is officially considered a worm farm until recently. My worms had been in my compost bin, which wasn’t layered in any particular way. A worm farm involves a slightly more complex layout, with several layers for food breakdown, a bedding area, and a drainage space for worm tea. The lowest box is partially filled with bedding, such as damp paper scraps. Worms are added here, and food scraps added on top of them. The worms will move upward as they eat, leaving castings behind them. They ultimately make their way through to the upper boxes. As they complete migration through each level, the castings can be collected and the newly empty box replaced at the top of the system.

The transition between levels is ultimately why I decided to switch from using worms in my compost bin to a true vermicomposting system. I continually add food scraps to my compost, which makes it difficult to retrieve the castings and finished compost at the bottom of my bin. With my worm farm, I can move boxes in and out easily.

With much appreciation to my boyfriend Liam for spearheading the construction of this project, here’s how we did it!

What we bought at Lowe's:

  • 2 planks of 0.75in x 3.5in x 8ft severe weather lumber for $4.97 each
  • 1 plank of pine corner edging for $7.76
  • 1 roll of ¼ in. 2ft x 10ft hardware cloth – it was the same price as this ½ in. hardware cloth for $12.02

We were able to get the 8ft planks of severe weather lumber cut in store at no additional cost to us. This only took a few moments in store, whereas it would have taken much longer at home. The planks were cut into 1-ft. sections.

In total, this cost us under $30!

At home, we already had a hammer, a wood staple gun, wire cutters, and a handsaw.

How we did it:

We started with our wood boards. After having been cut in store at Lowe’s, we were left with sixteen cuttings sized at 0.75in x 3.5in x 1ft. Because we had two planks, and there is some additional space eaten by the cutting blade, we ultimately got two end pieces that were slightly shorter than our other boards. We used these shorter pieces, and two additional pieces, for the top cover of the box.

With our remaining twelve pieces, we made three boxes. Liam nailed the boards together to form a mostly square shape. There was some slight bowing of the plank, but for less than $5 I can’t complain – besides, the worms won’t care.

Once we had the boxes together, I aligned them as well as I could, given the slight bowing. Definitely do this! If your boards aren’t in alignment, it will be hard to fit them together at later steps. Next, I cut out squares of the hardware cloth to fit on the bottom of the boxes. The hardware cloth squares were easily stapled to the boxes.

We wanted a sturdy worm farm, which is where the corner edging comes in. Having several boxes stacked on top of one another without anything holding them in place seemed slightly too precarious for my preferences. We devised a plan to use the corner edging to hold them together, while remaining flexible to move the boxes in and out as we please. To do this, we determined the length of each side, and Liam used the handsaw to cut a piece of the edging of that length for each corner. These pieces ended up being consistent with the printed measurement, 3.5in.

We decided to fasten the edges halfway down each box corner, so that it would overlap with the box below it, forming an interlocking system. To make sure the placement was the same for each box, Liam also cut a jig of half the length of each edge piece as a placeholder to determine where to nail the permanent fixture. It came out perfectly!

With all the boxes stacked together, we are very happy with the end product! The last step was to build a cover for the top of the system, which I did easily just by stapling our four remaining boards together. All that is left is to place a tray underneath the bottom box to catch the worm tea drippings, and if you plan to keep your worm bin outside, put a weight on the top of it so nothing can get in.

We were also very happy with the price point for this project, especially for under $30! Similar worm farm products are available on Etsy for $50 minimum, and also charge $50+ for shipping, so we saved a lot of money building our own.

If you’re wondering where you can get yourself some worms, I highly recommend Uncle Jim’s Worm Farm. That’s where I purchased my worms, which are red wigglers. They all arrived healthy and have done a great job in my compost bin, lasting through the harsh New England winter. Depending on the season, you may also be able to find red wigglers at your local bait shop or a sporting goods store that carries fishing supplies.

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