Montgomery County Resident’s Guide to Vermicomposting

Food Waste Background

The Montgomery County Department of Environmental Protection (DEP) Recycling and Resource Management Division estimated that approximately 56,000 tons of residential food waste were disposed of in the trash in 2017. Much of this waste can be prevented through weekly meal planning, creative cooking, freezing foods, and utilizing the best storage practices. However, some food waste is inevitable. You can reduce your environmental impact and create rich compost to nourish plants by composting your kitchen scraps. At home food waste composting with worms requires some work but has a huge positive impact.

Why Vermicompost?

Montgomery County currently provides  yard trim composting bins at no additional charge to residents. However, these bins cannot be used for food scraps. These compost bins are designed for composting only yard trim because they are completely open on the top and bottom and have aerating holes around the sides.

County processing capacity for food scraps is limited, so there is not currently a county-wide food scraps collection program. However, a program is being piloted in two neighborhoods, and only residents who have never previously had their food scraps collected for recycling are eligible.  Other residents who want to compost their food scraps may hire a collector who will pick up and deliver their food scraps to a composting facility in the region.

Outdoor rodent-proof bins and collection pickup can be expensive, and you may not live in the neighborhoods supported by the pilot program. Your space might be too small to accommodate two outdoor compost bins, or you want quicker results than outdoor composting in the winter (compost rates are slower when it’s colder). What’s the solution?

Compost indoors using red wriggler composting worms! This type of composting is called vermicomposting (vermi=worm). Indoor vermicomposting offers several benefits:

• Very efficient composting method.
• Easy and inexpensive to get started.
• Can be done indoors in a small place.
• Odorless (if done correctly).
• Can be a fun family project, especially for children.

How to Set Up Your Bin

1. Buy 1 18-gallon plastic bin and 2 lids.
2. Drills air holes of the same size around 1-2 inches from the top of the bin and around the lid to provide some air flow for the worms.
3. Cover the holes with screening material, such as window screening material (no metal material, though, as this can rust). This will make sure the worms do not escape. Use a waterproof glue.
4. Place the bin on top of the lid or other piece of plastic. For extra air flow and drainage, set it on top of some rocks or bricks. The bottom lid is to catch any extra liquid that drains out.
5. Add damp shredded newspaper to a height of around three inches.
6. Add your worms to the bin!
7. After a few days of letting the worms get adjusted to the bin, start feeding them.

Check out more detailed instructions here. 

The Worms

You’ll want to use red wriggler composting worms instead of the earthworms you find outside. Red wrigglers, specifically Eisenia fetida, prefer decomposing organic matter.

Worms can eat up to half their weight in food each day, but usually eat between 25-35% of their weight. To determine the best number of worms to start with, weigh your food scraps produced in one week. Then, order two times the weight of worms for your bin. For example, if your family produced 1 pound of food waste a week, you’ll get 2 pounds of worms for your bin. If you do not want to measure your food waste, starting off with  1 pound (approximately 1,000) of worms is a good bet. There are three places you can get your worms:

1. Order Eisenia fetida There are lots of companies that sell worms. You can expect to pay between $20-$50 for 1 pound of worms.
2. Contact your local USDA extension office.
3. Get the worms from someone else with a worm bin!

What to Compost

It might be helpful to print out or write down a list like and keep it on the fridge to help you and your family remember what to feed the worms.

Here are some feeding tips:

• When feeding the worms, make sure to bury the food under the bedding. This will help prevent fruit flies and odors.
• Always add food scraps to a different part of the bin every time.
• Feed the worms about once a week. They do not like to be disturbed often.
• Worm populations can double every three months! So, avoid overfeeding them at the beginning – they’ll be able to eat more later.
• Chop up the scraps into smaller pieces before adding it to the bin. This will help the worms digest faster.
• Cover food scraps with at least 2-3 inches of bedding.

Worm Bin Maintenance

The worms will not attempt to escape unless the conditions are off in the bin.

If the worm bin is too wet: add more dry bedding, unclog the drainage holes, and discard rotting food.

If the worm bin smells: you are probably overfeeding your worms. Get rid of rotting food and do not feed the worms for a week.

If there are fruit flies: Make sure you are burying the food under the bedding to avoid fruit flies. You can also put flypaper or other traps on the lid or nearby to catch the flies.

Worms are sensitive to light, so they prefer to be covered and kept in dark places. Laundry rooms, under the kitchen sink, or basements work well. Worms will die at freezing temperatures though, so avoid keeping them outside or in cold garages.

How to Use the Compost

You can harvest the compost once every few months using one of these methods:

1. Move all the compost and worms to one side of the bin. Add new bedding and food to the other side. After a few weeks, the worms will have migrated over, and you can remove the compost that is done.
2. Remove all the compost and put it on a tarp or other easy-to-clean material exposed to light. The worms do not like light and will crawl to the bottom of the pile. Remove the top of the compost pile every 20 minutes as the worms migrate to the bottom.

You can use the compost to nourish your plants in several ways:

• Mix with potting soil – up to 20% of the mixture can be vermicompost!
• Sprinkle a layer near the base of plants as a topdressing.
• Use some in seed-starting mixes indoors and outdoors.

Store harvested vermicompost in a container with a lid. If finished vermicompost becomes dry, it becomes difficult to incorporate into the soil and soil mixes.

Written by Fall 2021 Climate Fellow, Alyssa Bialek