Composting in bins with red wiggler earthworms is great for apartment dwellers, those who don’t have yard space, or for people who don’t want to hike to a backyard compost bin with their food scraps. By letting worms eat your food wastes, you’ll end up with one of the best soil amendments available—worm castings. This is a low cost, easily managed worm bin system.
MATERIALSTwo 8-10 gallon plastic storage boxes (dark, not see through!) Cost: about $5 eachDrill (with 1/4" and 1/16" bits) for making drainage & ventilation holesNewspaperAbout one pound of red wiggler earthworms
You can also BUY bins if you want a sleek system!
Step 1: Drill about twenty evenly spaced 1/4 inch holes in the bottom of each bin. These holes will provide drainage and allow the worms to crawl into the second bin when you are ready to harvest the castings. Step 2: Drill ventilation holes about 1 – 1 ½ inches apart on each side of the binnear the top edge using the 1/16 inch bit. Also drill about 30 small holes in the top of one of the lids. Step 3: Prepare bedding for the worms by shredding newspaper into 1 inch strips. I use the non colored pages and run them through my shredder. Worms need bedding that is moist but not soggy so I moisten the newspaper by soaking it in water and then squeezing out the excess. Cover the bottom of the bin with 3-4 inches of moist newspaper, fluffed up. If you have any old leaves or leaf litter, that can be added also. Throw in a handful of dirt for "grit" to help the worms digest their food.
Step 4: Add your worms to the bedding. One way to gather red wigglers- rather than the other types - is to put out a large piece of wet cardboard on your lawn or garden at night. Lift up cardboard to gather the red worms. In San Diego, a The Solana Center will supply you with earthworms to get started. Each worm can consume about 1/2 of its weight each day. For example, if your food waste averages 1/2 lb per day, you will need 1 lb of worms or a 2:1 ratio. There are roughly 500 worms in one pound. If you start out with less than one pound, don't worry since correct care will allow them to multiply very quickly. Just adjust the amount that you feed them for your worm population.
Step 5: Cut a piece of cardboard to fit over the bedding, and get it wet. Then cover the bedding with the cardboard. (Worms love cardboard, and it breaks down within months.) I also love a burlap fabric remnant cut to fit the top. It keeps moisture in and flies out.
Step 6: place your bin in a well-ventilated area such as a laundry room, garage, balcony, under the kitchen sink, or outside in the shade. Place the bin on top of blocks or bricks or upside down plastic containers to allow for drainage. You can use the lid of the second bin as a tray to catch any moisture that may drain from the bin. This "worm tea" is a great liquid fertilizer. To prevent ant attacks, you can run a finger's width of Vaseline around the base of your bottom bin, or the cups. They don't cross it. If you use cups to stand your bin off the ground, run Vaseline around the cup base. Step 7: Feed your worms slowly at first. As the worms multiply, you can begin to add more food. Gently bury the food in a different section of the bin each week. What do worms like to eat? Feed your worms a vegetarian diet. Most things that would normally go down the garbage disposal can go into your worm bin (see the list below). You will notice that some foods will be eaten faster than others. Worms have their preferences too. Here's a guide to what mine eat.
Worms LOVE:Banana peelsCereal and grains Coffee grounds & filterEgg shells in small amountsFruitTea bagsUnbleached paper towels - mine are Costco Vegetables
Worms HATE:Citrus Dairy ProductsFats MeatFecesOils
Step 8: Harvest your soil. Try either A or B to see which is best for your space and style.
A) Quick but messy: To separate the worms from the compost, empty the contents of the worm composter onto a tarp or old plastic tablecloth. Worms hate light and will wiggle into the pile. Wait a few minutes.Then with your trowel or your hands, remove the top layer of the compost pile until you see worms. Then wait again, be patient, and continue removing the compost. Repeat until thôere are lots of worms in a small pile. All the worms can go into the next iteration of the compost box, or half can start another compost box.
B) Slow and neat: Make a second, identical compost bin by repeating Steps 1, 2, and 3. Take the lid off your first, full composter, and place the second bin directly on the compost surface of the first. Then repeat Step 5, putting kitchen scraps in the second box, and put the lid on the second box. In 1–2 months, most of the worms will have moved upstairs to find the food there. The first (bottom) compost box will contain mostly vermicompost.
When the first bin is full and there are no recognizable food scraps, place new bedding material in the second bin and place the bin directly on the compost surface of the first bin. Bury your food scraps to the bedding of the second bin. In one to two months, most of the worms will have moved to the second bin in search of food. Now the first bin will contain (almost) worm free vermicompost. (You can gently lift out any worms that might remain, and place them in the new bin, or put them into your garden!)
Troubleshooting
Problem. A) Probable Cause. B) Solution
1. Worms are dying or trying to escapeA) You're keeping it too wet. The bedding is too dry. Bedding is used upB) Add more bedding Moisten bedding. Harvest your bin
2. The bin smells A) Not enough air. Too much food. Too wetB) Drill more ventilation holes. Do not feed for 1-2 weeks. Add more bedding 3. You have fruit fliesA) Exposed foodB) Bury food in bedding