DIY Industrial Worm Bins For The Home Gardener...

This article has been updated again - See the update near the bottom.

One idea we had is to create industrial sized worm bins to help create rich compost (worm castings) and to help digest all the sod and weeds we will be removing to make way for edible plants. Based upon some materials we have on hand, we originally decided on a 12 foot by 12 foot by 1 foot high bin that is divided in to three bins. Our version 1 plan called for the bin to be divided in to three 12 foot long sections. Had we not had these materials we still thought would have used 2x12 boards and in the end that is exactly what we did.

Version 1 Materials: We will be using 2 by 12 by 12 boards (1.5" x 11.5" x 12') we had on hand that used to be an old planter box and an old retaining wall. We bought shade cloth locally at a nursery for $18 and are reusing old stakes from an earlier garden fence project. We will also be using worms from our small three level home worm bin. This will make the cost of the project only $18 plus the black plastic cover. You will need fasteners like screws (3" and 1") for attaching the boards and adding the top/lid.

"Imagine having 144 cubic feet of worm castings, or better yet, 200 cubic feet!"

Choosing a site was somewhat of a challenge. We wanted the worms out of the heavy rain and hot sun, yet we also wanted to be able to fill and empty the bin somewhere convenient that we could get to with a fully loaded wheelbarrow. We found an out-of-the-way spot on one of the corners of the property where we had already been dumping sod and weeds and such. This meant I needed to pitchfork at least 2 cubic yards of very heavy compost at least twice - once out of the way and once back in the bins. But at least I did not have to move the compost across the yard. I pitched some onto to an old tarp and some behind where the bin will go. I moved a lot of gravel as I did not want as much gravel under the bin and we replanted any daisies or other flowers that might get squashed or trampled.

On the bottom is shade cloth (shade cloth allows water to pass though) and on top one can use plastic or tarps or the like. The sides, as mentioned, are 2" x 12" x 12' with additional stakes for support. The total area of this bin is roughly 12 feet wide by 12 feet long by 1 foot tall which equals approximately 144 cubic feet. Imagine having 144 cubic feet of worm castings! By making the bins side by side we (in a sense) gain a free bin compared to having one or two long bins. This will make covering the bin more difficult but we will not have to cover the bins very often compared to the luxury of gaining another bin. Most people might have a flat spot for a bin that they just need to build their bin upon without all the moving and flattening. For us, the sooner this is built, the less we have to move twice.

Version 2:

After getting the site flattened, other ideas were introduced and the design was modified to version 2. Instead of making the bin 12' by 12' we went with 10' by 20' which makes for a sizable 200 cubic foot bin. This required clearing a flattening a larger area. The version 2 bin is divided down the center making two 5' by 20' bins. We decided on 6 mil black plastic for the bottom and made trough like indentations in the soil below the plastic in each bin. This trough will allow us to collect the worm tea as it gathers in the trough and flows down hill to the bottom of the bins. The black plastic is 5' by 25' per side and thus continuous with a little extra to spare. The image above is the bin being built.

Version 2 Materials: We used 2 by 12 by 20 boards (1.5" x 11.5" x 20'). We bought 10' by 100' 6 mil Black Plastic Sheeting like you find on Amazon and are reusing old stakes from an earlier garden fence project. We will also be using worms from our small three level kitchen type worm bin. You will need fasteners like Deck Screws (3" and 1") for attaching the boards and adding the top/lid. We used the kind that are made for cedar and do not rust or stain. You could use 1 by 2 for holding down the plastic also. We rolled the plastic on our strips of wood on the short ends of the bin and screwed that down. We then laid the strips on the plastic for the long sides of the bin and screwed them down. Having the plastic compressed under the wood strips helps the plastic not just tear out.

For this version of the bin the plastic will just be laid in the bottom rather than pinned under the sides. By laying the plastic in we can replace it if needed. We can also use it to help herd the worms or worm castings out of the bin (after the bulk of the castings are removed) by grabbing the plastic and pulling it the length of the bin so it scoops the casting along towards the end of the bin. More images coming soon.

UPDATE:

We loaded up the bin with a huge amount of compost-able sod and weeds then proceeded to hose it down so there would be enough moisture for worms. Seemed smart to add water since it is the middle of summer. On top of that we placed tissue for worm bedding, worm castings full of worms and more tissue. We wanted the worms to start out in the same exact stuff they are used to since they were being moved from their old home (a kitchen size (1.5 square foot worm bin) to their new home which is a worm bin the size of a kitchen (100 square feet)! We also felt to start them at one end of the bin in a concentrated mass.

At that point we sealed the bin with 6 mil black plastic using wooden strips. The strips were just the scrap cut offs (1/4" thick and 1.5" wide or so) from ripping 2 by boards on the table saw. Since the plastic is the full width of 10 feet wide we folded that over and pinned it down with wood to be ready for when we fill the other bin.

Other Thoughts: We used plastic as we could not think of something better at the time. At some point we will make part the lid easier to open to check on the bin. We might add a soaker hose to the next version if while using this bin we find that might help. Clearing the hard packed gravel that was loaded with weeds and making the ground flat took enough time and effort that the bin had no real frills other than the trough at the bottom. We still need to add and reposition some support stakes. On the outside (near the middle) of the bin we will add stakes and near the corners we will cut the stakes off level. Now that the bin is made we can further refine it. Ideas welcome...

The next installment of this article will go here...

Links:

1Check out Vermicompost for more info...

2Check out Compost for more info...

3Check out Mulch for more info...

4Check out Permaculture for more info...