Vermicomposting: How to turn waste into compost over winter

Vermicomposting with worms turns food and other organic waste into nutrient dense compost.

Traditional outdoor composting slows or stops in cold weather due to low outdoor temps. Vermicomposting can be done indoors. It is an effective way to manage food waste over winter, plus it creates plenty of dark, rich compost to start seeds in spring.

Additional benefits of vermicomposting

• Worms speed up the breakdown of organic matter, so compost is finished faster.
• Castings (worm manure) enrich humus (final compost product).
• Vermicomposting can be done in very small spaces indoors.
• Compost leakage can be used to feed and water houseplants during winter.
• Data confirms vermicompost has higher levels of nutrients than traditional compost.

Start an indoor worm farm in 10 steps

Supplies:

• Composting worms
• Worm housing
• Cardboard
• Newspaper
• Soil
• Food waste — FEED bread, grains, coffee grounds, tea, fruits, vegetables, leaves/ plant clippings. DO NOT FEED meat, fat, dairy, feces.

1. Starter kits and bins are available for purchase online ($50-$200). Alternatively, make your own worm housing from 10 gallon Rubbermaid containers. Free instructions can be found at http://whatcom.wsu.edu/ag/compost/easywormbin.htm
2. Purchase composting worms from a reputable vermiculture supplier. There are several species of worms to choose from.

Worm populations self-regulate according to available food and space. In my 10 gallon worm farm, 1lb of Red Wrigglers doubled population size in 3 months, then held steady.

3. Place your bin in a dark, well-ventilated area.
4. Maintain temperature between 40-80 degrees F.
5. Place a tray beneath worm farm to collect leakage. Leakage can be used to feed and water houseplants.
6. Prepare bedding. Cut 1 inch strips of newspaper. Soak in warm water. Wring out excess water. Fill bottom 3 inches of bin. Do not let bedding dry out.
7. Scatter a few cups of soil over prepared bedding.
8. Add worms and feed. Start by gently burying 1 cup of chopped food scraps in bedding. Burying food in bedding helps minimize smell, fruit flies and rodents. Feed every few days. Increase food steadily. Check worms often.
9. Cut a piece of cardboard that will loosely sit on bedding. Moisten it with water and set it on top. A moist cardboard inner cover helps insulate and maintain moisture levels. Set Rubbermaid lid on bin as an outer cover.
10. Compost is ready to harvest in 3-6 months, depending on how many worms you have and how much you feed them.

How to harvest vermicompost

There are more ways than one to harvest vermicompost, but the quick and easy method is side-to-side harvesting. Side-to-side is accomplished by feeding the worms on one side of the bin for a few weeks. The worms will migrate to that side, allowing you to harvest the vermicompost from the unoccupied side of the bin.

Put new bedding in the side you’ve harvested. Feed worms on the fresh side only for a few weeks. The worms will migrate to the fresh side, allowing you to harvest the remaining vermicompost.