Composting With Worms
Editor’s Note [Updated on May 9, 2011] – This article was originally written in April 2007. Please see the following links for updated, more timely information concerning composting:
- Composting in the City – How to compost without a yard, little space and virtually no time.
- The Next Wave in Composting – What to do with the “biodegradable” and “compostable” products.
- Guide to Composting in the Winter – When the temperatures outside fall, so does your compost’s efficiency. Here’s how to prepare.
- I Got Worms! Composting and You – Vermicompost, or composting with worms, is a great first step before you commit to a large compost pile. This guide will show you how to get started.
- Cheat Sheet: Composting - Feel behind on the talk about compost? This article breaks down composting, its benefits and whether or not it’s right for you.
ORIGINAL ARTICLE:
Let worms eat your organic waste! They will happily turn it into some of the best fertilizer on earth – worm compost, otherwise known as “worm castings” or “vermicompost.”
Only a few things are needed to make good worm compost: a bin, bedding, worms and worm food. By following the steps listed below, you will learn to make, maintain and use your own worm compost.
Only a few things are needed to make good worm compost: a bin, bedding, worms and worm food. Photo: Howstuffworks.com
Worm Bins
Your bin needs to be only 8 to 16 inches deep, since compost worms are surface feeders. You can build your own bin by using a washtub, dish pan, used shipping crate or a commercially available worm bin. Just be sure your bin has a lid to keep out flies and rodents. It also needs holes in the bottom (a quarter inch or smaller), for ventilation and drainage.
The rule of thumb for bin size is two square feet of surface area per person, or one square foot of surface area per pound of food waste per week. Because worms like moderate temperatures, place your bin in a shady location where it will not freeze or overheat. Some good locations include:
- Kitchen corner
- Garage
- Basement
- Patio
- Outside the back door
- Laundry room
Bedding Materials
Black and white newspaper is the most readily available and easy-to-use bedding material. Tear it into strips about one inch wide and moisten so it is as damp as a wrung-out sponge. Cow or horse manure can also be used to lighten bedding and absorb excess moisture.
A handful or two of soil, ground limestone or well-crushed eggshells every few months are good for providing grit and calcium. Fill your bin with moistened bedding, toss in a few handfuls of soil, and you are ready to add the worms and food. Over time, the bedding and food are eaten by the worms and turned into dark worm compost.
Worms
The best kind of worms for composting are “red worms” or “red wigglers.” They are often found in old compost piles, but are different from the earthworms you would normally find in the ground. These worms have a big appetite, reproduce quickly and thrive in confinement. They can eat more than their own weight in food every day! When purchasing red worms, one pound is all you need to get started.
Feeding Your Worms
Worms like to eat many of the same things we eat, only they aren’t so picky. Some of their favorites include:
- Stale bread
- Apple cores
- Orange peels
- Lettuce trimmings
- Coffee grounds
- Non-greasy leftovers
- Vegetable scraps
Begin feeding your worms only a little at a time. As they multiply, you can add larger quantities of food waste. Bury the waste into the bedding regularly, rotating around the bin as you go. When you return to the first spot, most of the food you buried there should have been eaten. If not, don’t worry. Just feed the worms less for a while.
Methods for Collecting Your Finished Worm Compost
After you have been feeding your worms for three to six months, you may notice the bedding has been eaten, and you can begin harvesting the brown, crumbly worm compost. Harvesting the compost and adding fresh bedding at least twice a year is necessary to keep your worms healthy.
Method 1:
Move the contents of your worm bin to one side, place fresh bedding in the empty space and bury your food wastes there for a month or so. Harvest the other side after the worms have migrated to the new food and bedding.
Method 2:
Remove one-third to one-half of the contents of your bin, worms and all, and add the worm compost to your garden soil. Add fresh bedding and food to your bin.
Method 3:
Spread a sheet of plastic out under a bright light or in the sun. Dump the contents of the worm box into a number of piles on the sheet. The worms will crawl away from the light into the center of each pile and you can brush away the worm compost on the outside by hand. Soon you will have wriggling piles of worms surrounded by doughnut-shaped piles of worm compost.
Using Your Worm Compost
Worm compost is more concentrated than most other composts because worms are excellent at digesting food wastes and breaking them down into simple plant nutrients. Use it sparingly for best results.
Mulching and Amending Soil
To mulch with worm compost, apply a one-inch layer to the soil around plants. Be sure the worm compost is not piled against plant stems. To amend soil, worm compost can be spread one-half to two inches thick over garden soil and mixed in before planting, or mixed into the bottom of seeding trenches or transplanting holes. You can also mulch your worm compost into:
- Houseplants: Sprinkle worm compost around the base of plants to fertilize. Each time you water, plant nutrients will seep into the soil.
- Potting Mixes: For healthy seedlings, mix one part worm compost with three parts potting mix or three parts sand and soil combined. Peat moss, pearlite and worm castings are also good ingredients to add.
Warning Signs
Some symptoms that your worm composting is not going as well as it could are:
- If your worms are dying
- If your bin smells rotten and/or attracts flies
Worms Dying
If your worms are dying there could be several causes:
- It may be that they are not getting enough food, which means you should bury more food into the bedding.
- They may be too dry, in which case you should moisten the box until it is slightly damp.
- They may be too wet, in which case you should add bedding.
- The worms may be too hot, in which case you should put the bin in the shade.
- The bedding is eaten, and it is time to add fresh bedding.
Bin Smells
If your bin smells rotten and/or attracts flies, there may be three causes:
- First, it may be that there is not enough air circulation. In this case, add dry bedding under and over the worms, and do not feed them for two weeks.
- Second, there may be non-compostables present such as meat, pet feces or greasy food. These should be removed.
- Third, there may be exposed food in the bin. In this case, secure the lid, cover food scraps with bedding, and cover worms and bedding with a sheet of plastic.
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