DIY : How to Start a Worm Compost Bin – Bethany Frandle – Medium
How to Make a Worm Compost Bin
When starting a worm compost bin, you can build your own or purchase one.
You will need the following items to build your own worm compost bin:
- Plastic storage bin with lid — it should be opaque and have a depth of eight to twelve inches
- Power drill or other mean of making holes
- Newspaper and cardboard
- Note: Most colored ink is toxic to worms, so never use paper with colored printing on it for bedding.
- 2 cups of soil
- Worms: Red wigglers (Eisenia fetida) and/or redworms (Lumbricus rubellus)
- Note: Be sure that your worms are not an invasive species in your area and that they pose no environmental threat. This can be done with a quick Google search.
How to Construct Your Bin
- Drill holes in storage container lid. Create two rows of holes for ventilation near the top of the bin. The holes should be three to four inches apart, and they should be ¼ inch or less in diameter. Don’t put any holes in the bottom — this way the bin can be stored anywhere and not leak. Note: If you store your bin outside, be mindful of when it rains. Without drainage holes, the contents can get too soggy, or the worms can drown.
- Shred plain newspaper into small strips — you can do this by tearing or by putting the newspaper through a shredder. If you have plain, corrugated cardboard that is free of bleaches and inks, you can tear it up into squares with four inch sides and soak in water overnight.
- Wet the newspaper strips until they are damp, like a wrung-out sponge, and place them in the bin by the handful. Remember: you don’t want water to collect at the bottom of your bin, so make sure the newspaper isn’t too wet. Add four to six inches of newspaper.
- Place the cardboard pieces to your bin, add the two cups of soil, and mix it all together.
- Put some newspaper over the worms right away as they dislike light.
Where to Put Your Bin
Place your bin in a place that is safe, quiet, and out of direct sunlight. Worms do best in temperatures ranging from 40 to 80˚F, so be mindful of where you place them. If where you live experiences harsh winters, you’ll need to keep your bin inside during the winter or only compost seasonally. If your bin is inside your house, be sure the lid is tight. Dogs will eat just about anything, and cats like to play with worms. If your bin is outside, secure the lid somehow to keep racoons, skunks, chickens, and other creatures out of it.
What to Feed Your Worms
- Worms will eat any vegetable scraps — fresh or cooked
- They will also eat coffee grounds, tea leaves, eggshells, fruit (except citrus), oatmeal, other cooked grains, squash, bread, pasta, and other bread-like things.
- They will eat rabbit droppings, newspaper, and uncoated cardboard.
- Don’t intentionally feed your worms dairy or sugar, but if there are small traces of these on other scraps, it’s okay.
- Never feed your worms citrus of any kind, meat, bones, vinegar, oil, or salty/processed food.
- Never put glass, plastic, aluminum, rubber, or sponges in your compost.
- Never mix fresh cow, horse, or chicken manure into the bedding. As they decompose, they emit heat-trapping gasses.
How to Feed Your Worms
Worms are capable of eating their weight in scraps a day, but the actual amount they eat on a specific day can vary significantly. It might take worms a few months to start eating a lot, so be careful about overfeeding as the worms begin establishing the bin. Overfeeding can cause smell and attract insects.
Begin by feeding just a cup of scraps the first day. Bury the food waste in the corner of the bin and be sure to cover it with an inch or so of newspaper. A few days later, add another cup of scraps in a different corner. Feeding them small amounts about once a week should be enough and try to judge how much is too much. If you begin to notice a bad smell, feed them less as the smell is coming from scraps they haven’t been able to eat. As time pases, they will eat the food scraps, newspaper, and cardboard, and produce worm castings.
Worms like to eat rotting food, which is why it can take a few days before they start eating the food you give them. They will eat soft food before eating harder foods, and it’s better to rip up bigger scraps into smaller pieces so they can eat easier. Worms won’t eat seeds, so they could grow where you put the castings.
How to Maintain Your Bin
Try to keep your bin moist — remember the wrung-out sponge example. Consider purchasing a spray bottle and mist the paper to keep it from dying out. You might have to do this more in the beginning of your bin’s life. Worm castings hold water, so as they appear they will help keep the bin moist. The challenge is finding the right water level. It needs to be damp and airy. If it becomes too soggy, mix a few handfuls of dry newspaper and fluff the bin.
One way to determine if it’s too wet is by the behavior your worms. If your worms are congregating on the sides or lid and trying to escape through the air holes, your bin is too wet. If you’re struggling to keep the bin dry enough, cut a hole out of the lid and put window screen in its place with duct tape. Remember: your worms need protection, so simply taking the lid off could cause them to be eaten or be exposed to too much light. Be mindful of where you put your bin.
Keep your contents between six and eight inches. Having too much stuff in your bin could turn the bottom into an inhospitable environment for your worms. If you think you have too many worms, start a second bin, gift them to a friend who is interested in a worm bin, or feed them to a chicken. You could also distribute some into a compost pile, but be sure that the worms you have won’t disrupt the natural ecosystem.
Every now and then, dig through the bin to check if there is any standing water on the bottom. If there is, clean it out. This water could create some bad smells or kill your worms. If your worms are happy, they will reproduce. You’ll know this is the case if you see small, baby worms in the mix and worm cocoons, which are small, lemon-shaped beads. If you begin seeing mites, pot worms, or tiny black beetles in your bin, there is no need to worry. They are other decomposers and will help your worms out. Lastly, if you go on vacation, add fresh newspaper and feed the worms well.
What to Do With Your Compost
When your bin has more castings than anything else, you will need to harvest it. Don’t add new food for a few days, and then put squash, or another worm favorite, on one side. Wait a few days for the worms to migrate, and then scoop out the material opposite to the squash during the day. Place in on something hard, such as the lid, and form the pile into a pyramid shape. The worms, in an attempt to escape the light, will migrate to the bottom. Take the castings from the top of the mound and put them in a bucket, checking to make sure you didn’t take any worms with. Put the worms back in their bin, add fresh (moist) newspaper, and mix the contents of the bin up. Begin feeding regularly.
As mentioned earlier, castings are very wet. In order to store them for future use, you need to spread them out and let them air-dry for a few days. Once dry, sift them with a screen or a colander to catch any remaining food scraps. You can store them in a bag or container. Worm castings are rich in nitrogen, phosphorus, potassium, and some micronutrients. This means they are great as soil conditioners. You can mix it with your potting or garden soil or as a top dressing for your plants.