How to Build a Vertical Worm Compost Tower
Using a vertical worm compost tower is a great way to introduce worms into any garden while also speeding up the process of composting. Worms provide a vital role in the health of gardens, and composting adds vital nutrients to any type of soil. Adding worms to compost can speed up the process and make the finished product more nutrient-rich and beneficial for plant growth. Let’s take a look at a simple project that can be used in any garden to boost plant and soil productivity.
4 pieces of lumber that are at least 5” wide and 1” thick
Wood for the cover
The first step is to build the worm tower. You can make it as big or as small as you like depending on your space requirements and the amount of material that you want to compost. However, you should work with a tower that is at least three feet tall and 5 inches wide for practical purposes. You can also use any type of wood that you have available. However, try and avoid treated, painted or stained wood as they may leech toxins into the compost pile as well as into the worms. These can get transferred to your food supply later on.
Preparing the Wood
You want to bore a series of holes along the bottom 6 inches of each board. These will be driven into the ground and allow the worms to enter and exit the compost pile. They will enter to feed and then exit to burrow, reproduce, fertilize and colonize your garden. The holes should be around ¾ to 1 inch in diameter, and each board should have a series of them that are around an inch apart. If you’re working with 5” wood, there should be 5 or 6 holes in each piece. Remember, you have four pieces that make up the walls of this tower. Bore the holes with a dremel or similar tool.
The next step is to simply screw the four pieces of wood together and make sure they are secure. Not only do you want at least two screws to connect the tops and bottoms of each board, but you should also insert a few screws along each side as well. Space the screws around 4 inches apart in order to minimize warping and bending. These gaps can cause compost to fall out, reducing heat within the compost pile and enabling insects to enter. While many insects are fine, there are a few common species that can degrade the compost as well as pose a health risk to the worms. In other words, make the tower as sealed as possible.
Installing and Filling the Tower
Once you’ve built the tower, simply choose a location in your garden, dig a hole and insert the the tower. Make sure that the hole is deep enough to cover the holes in the wood before packing some dirt around the bottom to hold it in place.
Next, add a few inches of potting or garden soil to the tower. Then add about 2 cups of shredded paper, peat moss, finished compost or coconut fiber on top of the soil layer.
Next, add the earthworms. The amount that you add will depend on the size of the tower as well as how much compost you will be using. A couple of handfuls should be just fine for a tower that’s about 3 feet tall. Then add about a cup of fresh kitchen scraps, such as plant material or peelings from fruits. Never introduce meat or dairy products into the tower. This can attract vermin, insects and cause harm to the worms. It can also introduce bacteria into the system that can spread to your crops. Put the lid on and you’re good to go.
Check the tower about once a week to see if the worms have eaten all of the kitchen scraps. The exact amount of time will vary based on your tower, how many worms you are using (along with their species) as well as the amount of scraps you put in the tower. In most cases, you can expect to refill the tower every week or two. Don’t over-fill it otherwise the food scraps will spoil and the worms won’t eat it. This will take a little bit of trial and error, but it’s worth the effort over the long run.
Now all you have to do is wait until the upper layer of the compost pile has turned black. It will resemble dirt. You can now transplant it, along with excess worms, into your garden or continue to add scraps as necessary. Try this trick for yourself, and feel free to share any insights that you may have to make this project more effective.