R4: Compost

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Vermicomposting at Home

Benefits

Composting at home is an efficient way of adding value to your garbage and decreasing greenhouse gas emissions. Vermicompost is ideal for apartment-dwellers, for those who already have a garden composter but who wish to make compost indoors in the winter or for those who wish to produce superior fertilizer for their indoor plants.

Vermicomposting, using special earthworms to eat organic waste, can be done indoors. It is odourless, doesn't require mixing and yields vermicast which is a rich organic fertilizer that harbours beneficial bacteria, fungi and micro-organisms that normally coexist in a healthy, balanced soil ecosystem. According to agricultural research, vermicompost is sometimes considered better than compost in terms of plant growth and yield.

When you add compost to indoor plants, some worms may end up in the soil, This is actually greatly beneficial since vermicast production is continuous and is distributed around the roots, burrowing channels provide aeration and secreted mucous allows for better moisture retention. However, you should avoid releasing vermicomposting earthworms outdoors because they are not native to Canada. Simply sort your compost well or freeze it before you use it outdoors.

Worms

The best type of worms to use is Eisenia foetida, also known as red wrigglers, since they are used to living in rich organic soils, they reproduce the fastest and they eat the most (half of their own weight in a day under optimal conditions). Do not use those big grey earthworms you find outdoors when it rains; these will not be happy in a vermicomposting bin.

Bin

Use a non-toxic plastic container with a tight fitting lid and aeration holes. Use shallow containers because composting worms only live and eat in the top 20 cm of the soil.

Gravel

To provide sufficient drainage and aeration for the bin, rocks should be laid down at the bottom of the bin.

Bedding

Worms cannot live solely in food waste. They need bedding to live in when not eating so that they can stay away from the acidic micro environment of decomposing food. The best bedding material is soil (use finished compost or take it from a dead potted plant). Some recommend using only newspaper as bedding but this is not like the worms’ natural environment and they may then be more sensitive to decreased feeding bouts when you go on vacation.

Newspaper

Newspaper is useful to cover the top of the compost inside the bin although there is already a lid. The lid doesn’t directly touch the compost as the newspaper does. The newspaper retains humidity in the bin, discourages drosophila (flies), and provides the worms with food. The fact that worms can eat newspaper means that no food needs to be added while on vacation, for example, and the worm population will still be able to survive for about a month.

Nitrogen rich waste

Good to vermicompost:
• All raw fruit and vegetable scraps
(including banana and citrus peels)
• Coffee grinds and filters, tea bags
• Egg shells (dried, crushed)


Avoid:
• Transformed food (with oil, grease or vinegar)
• Bread or other dough, meat/dairy products
• Large amounts of already stinking rotting waste
• Contaminated materials (feces…)

Carbon rich waste

Good to vermicompost:
• Leaves, twigs (indoor plants), dried grass clippings
• Newspaper (b+w ink), Paper, brown paper
• Cardboard boxes, egg cartons
• Soil and roots from a dead potted plant

Avoid:
• Coloured ink or glossy magazines
• Excess of bleached paper
• Leaves from outdoors (they have bugs)
• Contaminated materials (used Kleenexes…)

Habitat parameters

Temperature
The ideal temperature range fpr mating and depositing egg capsules is between 16°C and 25°C.

Humidity
The perfect humidity is between 60-80%. Damp soil becomes rapidly depleted in oxygen givng rise to a foul smell. If you squeeze compost in your hand, it should feel like a moist sponge.

pH
Worms prefer neutral pH (6-8) and their activity normally maintains the pH viable. If you eat a lot of citrus, help to neutralise the acidity by adding egg shells.

Light
Avoid overheating your bin by protecting it from direct sunlight. Light outside of your bin should discourage worms from wandering astray.

Soil disturbance
Worms mix the compost themselves. Aside from digging to bury food or harvesting, avoid mixing which can interrupt worm feeding and mating.

Troubleshooting

When you set your bin up and introduce new worms, keep the room's light on 24h for a few days to prevent worm migrations. When you start vermicomposting your colony is small, so start by adding only a bit of food at a time. If the worms avoid the bedding, if foul smells occur, if leachate is a problem, if your colony dramatically reduces in size, if food waste doesn’t fully degrade before you add some more, check aeration, moisture and pH. A troubleshooting guide is available at: http://r4.concordia.ca travque@yahoo.com