Vermicomposting, or using worms to break down waste materials, is a fast and effective way to turn kitchen scraps into worm castings, a highly valued form of compost. Food scraps traveling through a worm's body is just about the most incredible thing that can happen to soil.
After being eaten, digested and then pooped out by worms, soil will be 5 times richer in nitrogen, 10 times richer in potassium, and will have 7 times as much phosphate, 1.5 times more calcium, and 3 times as much magnesium. Worm casting compost also contains enzymes and beneficial microbes that speed up the soil food web and help plants grow more vigorously.
Functionally, the main activity in a worm's life is digesting. Darwin was lavish in his praise of them, citing that they accomplished their life's goal of digestion flawlessly, rarely suffering illnesses or obstacles to set them back. In fact, his final book was devoted to trying to understand their impressive ability of turning death and decay into soil that is powerfully alive.
An excellent review of Darwin's experiences with worms and their worldwide importance is the book The Earth Moved by Amy Stewart. You can harness the digestive power of worms in your own kitchen or back porch by setting up a worm bin. Worms will turn your food scraps and other waste organic material into a soil amendment that is made quicker and of higher quality than traditional compost, and with little to no smell.
Setting up a Worm Bin
The essential components of any worm bin is a set of stackable bins that have holes through the bottom to allow the worms to travel from the bottom bin upwards as the they travel to the fresh food scraps at the top. My husband and I have been using the Worm Factory produced by Nature's Footprint which retails for about $80. It's a great system and we love how simple it was to set up and use.
However, if you want to go the DIY route there are many plans online that require only supplies you can buy at a hardware store. One especially good and straightforward plan can be found here.
Getting Your Worms
The best species for worm bins is Eisenia fetida, or the red wriggler. This species thrives in organic trash, reproduces quickly in the conditions of a worm bin, and is used to living in only a few inches of soil. It is recommended that you start with 1 pound (or about 800-1,000 worms) at the beginning. Too few and they won't reproduce quickly enough to get the system running at full capacity.You can buy your worms from many sources:
1. Mail order worms: Many companies will ship you a container full of worms. We ordered ours through Uncle Jim's Worm Farm and our worms came quickly and alive.
2. Local farms: Check out Find Worms to find a nearby worm farmer.
3. Find a vermicompost friend: since worms are constantly reproducing, many small-scale worm composters will be happy to give you some of theirs
4. Bait shop: many bait shops sell red wrigglers as bait. Just be sure to look for the Latin name Eisenia fetida to make sure you are getting the correct species
Preparing the Worm Bin
Prepare your worm bin before your you introduce the worms. The bottom tray is the base of the system and should consist of moistened bedding material (like shredded newspapers). Bedding is essential for airspace and allows excess moisture to drain through the bed and into the collection jar. Add a few cupfuls of garden soil into the bedding to inoculate it and introduce beneficial microbes to the system that will begin to break down the food for your worms before they arrive.
Preparing a Feeding Tray
A feeding tray is the top bin in your system and the only one that you will be adding food scraps to. To create it, start by covering the bottom of the tray with one or two sheets of dry newspaper. This is only for the first feeding tray, not for the ones you will be adding weeks later.
Next, add moist bedding material evenly across the newspaper. This includes carbon-based material like cardboard, paper and junk mail, unsalted nut shells and dry leaves. In one corner, add 2-3 cups of food scraps which can be fruits and vegetables, coffee grounds and tea bags, and pasta or cereals.
Note: Do not use animal products, anything coated in vinaigrette or heavy sauces, or much citrus. These products are hard for worms to digest and will slow down your system. Place moist newspaper on top of of the food and put a lid on the bin. After this initial feeding, plan to feed your worms equal parts bedding material and food scraps.
When the worms arrive, place them and any material that they traveled with under the wet newspapers in the top feeding tray of your worm bin. Your worms will likely be stressed when they first arrive, so expect about a week for them to acclimate to their surroundings and begin their frenzied eating.
To prevent them from trying to leave the composter through the top, shine a bright light on the bin for the first few days. This will cause them to burrow deeper into the bedding and will allow them the time to acclimate. Once they are comfortable, they will begin to move around and eat.
Adding Additional Trays
Add food scraps and bedding material into the feeding tray whenever it seems to be getting low. When your worms have filled this first tray, it's time to add a second tray to the system. Use a tray of similar size to the one below it, but make sure it can stack inside it. The newest tray will be the new feeding tray and the filled feeding tray will become a processing tray.
Remove the newspaper from the top of the old feeding tray and line the new feeding tray with shredded bedding material. Add two to three cups of food and cover the top with wet newspaper and put the lid back on. After a day or two, you should see worms in the top feeding layer, meaning that they have migrated upwards. To keep the worms migrating through the layers, do not put food in any other tray than the top feeding tray.
Harvesting Your Worm Compost
As you build up your worm bin system with multiple processing trays, the worms will migrate to the top layers and the bottom processing trays will be left with nutrient rich, microbially-enhanced worm castings mixed with bits of decomposed organic matter. This process typically takes 3-4 months.
When this material is black and chunks of matter are small and crumbly, the worm compost is ready to be used. Plan to harvest the finished vermicompost when the top feeding tray is full. Pull all trays off the bottom tray and put them to the side, keeping them stacked in order. Now put the bottom tray on top of the other trays, leaving the lid off so that light can hit it.
You can also use a small hand rake to shift the compost to expose the worms to light. This will startle any worms still in the compost and draw them down into the feeding tray one tray below. When you are confident that all the worms are out of the tray, you can take the soil out and store it until you are ready to use it.
Using the Finished Vermicompost
Not only do worm composters prevent a large amount of household wastes from going to the landfill, they also provide the user with an unparalleled soil additive to use in their gardens or planter pots. Use the castings as you would commercial fertilizers. They will not burn plants and can be worked into the soil before planting seeds or bedding plants.
They can also be used to periodically top dress around the base of plants, or as an ingredient in potting soil. Castings discourage many plant pests and strengthen plants against diseases. By soaking worm castings in water, you can also make a great liquid fertilizer that will give a pro-biotic boost to your plants by allowing them to absorb the nutrients more quickly than from dry castings.
A vermicomposting system is a great way to become a more responsible disposer and maintain healthier plants. Be warned, they are addicting! Once you start keeping worms, you may find yourself expanding your operation and even peering into your friends and neighbors scrap bins, wanting to take their excess produce home for your own microherd. Just make sure to share some of your castings!
Lydia Noyes is serving as an Americorps volunteer with her husband in West Virginia at the Big Laurel Learning Center. There, they live with two nuns and help to run a sustainable homestead mountain ridge retreat and ecology center that resides on a 500-acre land trust. You can follow her homesteading adventures on her personal blog Living Echo. Read all of her MOTHER EARTH NEWS posts here.
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