Compost is beneficial for lawns, gardens, trees, and potted plants. It adds organic matter to the soil, enhances the ability of the soil to hold moisture, increases soil porosity, reduces erosion, improves plant growth, and aids the development of healthy root structures. Composting also reduces greenhouse gas production and the amount of material sent to landfills, helps to recover valuable materials, and reduces water use.
Compost is easy to produce and apply to the garden. Just choose a method that fits your time and space requirements, and you can create a more environmentally friendly home and garden in a relatively short time.
There are a number of ways to compost, including bins, tumblers, trenches, piles, and vermicomposting.
Bins and tumblers
Regular compost bins can be built or purchased (many municipalities offer inexpensive bins and composting workshops). There are also tumbler systems commercially available. These are more expensive, but they produce good compost rapidly (in as little as 3 weeks) because the drum has a handle that enables daily turning of the compost. This aerates the mix, facilitating swift decomposition.
Trenches or piles
Many people don’t bother with a compost bin. Instead, they maintain a compost pile in a corner of the garden or bury kitchen and garden waste in an 8-inch trench and leave it to rot for several months, after which they plant above it. Trench or pile composting is easy, though it can draw pests to the garden.
Worm bin composting
A vermicomposting system can be kept outdoors or inside because it is completely enclosed. This type of system requires special worms that are suited to living in decomposing organic materials rather than garden soil (such as the redworm, also known as the red wiggler or manure worm). A vermicomposting system requires a layer of carbon-rich material that acts as bedding (shredded cardboard, paper, or dried leaves) to which kitchen wastes can be added. The worms consume and aerate the materials as they move through them and eventually convert them to worm castings, which make excellent compost.
How long does composting take?
Composting usually takes anywhere from a couple of months to a couple of years, depending on the effort you put into it and the materials used. Chopping or shredding materials and turning the pile regularly speeds the process significantly. If properly tended, composting should take 2-3 months, though letting the compost age for another couple of months is beneficial. If you don’t chop up the materials, it may take 4-8 months or more. Compost tumblers can reduce the processing time to a few weeks.
There are some materials that may take longer to break down in home composters, such as compostable plastics. Compostable plastics are made from organic materials (corn, potatoes, soy, etc.) that can decompose back into water, biomass, and carbon dioxide after composting. However, most home composting systems don’t produce enough heat to break these plastics down quickly, so the process may take a couple of months longer than with other compostable materials, and as long as 2 years for some compostable plastics. Commercial composters, which grind materials and generate more heat, can decompose these bioplastics more quickly.
Composting is complete when the material is crumbly and dark, with an earthy smell. You can remove completed compost from materials that are not yet broken down by sifting the material through wire mesh and then returning the partially decomposed items to the pile.
How to add compost to your garden
To extract the finished compost, remove the bottom layer of decomposed matter. Commercial bins have a door at the bottom for this purpose. If using a compost pile, you’ll have to remove the layers on top to get at the finished compost underneath. If you have sufficient space, you can have two compost bins or piles going at the same time so that you can draw from the finished pile while the newer pile carries on decomposing.
There are several ways to use compost in your garden, including adding a layer on top, applying as a tea, or making your own rich potting soil.
Use as a top dressing
Add a layer of compost on top of the soil and mix it in using a shovel or rake. You can add up to 6 inches for a new vegetable garden and 4 for an established garden (lawns require only about half an inch).
Make compost tea
To make compost tea, add compost to a cloth or burlap bag and submerge it in a bucket or barrel of water. The ratio should be approximately 5 parts water to 1 part compost. Steep the tea for a week, stirring a few times. Then use the compost tea to water your plants. The compost in the bag can be spread over the garden or added back to the composter.
Make potting soil
You can make your own rich potting soil by mixing 1 part compost, 1 part vermiculite, and 1 part soil or peat moss. Adding some organic fertilizer can help to improve growth, as compost often does not provide sufficient nutrients on its own.
- Compost Council of Canada. (2010). “The How Tos of Composting” and “Using Compost.” Compost.org.
- David Suzuki Foundation. (n.d.). “Composting Dos and Don’ts.” DavidSuzuki.org.
- Metro Vancouver. (n.d.). “Here’s the Dirt: Backyard Composting.” MetroVancouver.org.
- New Brunswick, Canada, Department of Environment. (n.d.). “Composting.” GNB.CA.
- Southern Idaho Solid Waste. (n.d.). “Compost FAQ.” SISW.org.
- VegWeb.com. (2009). “Composting Guide – Composting Fundamentals.”
- World Centric. (2011). “Compostable Plastics.” WorldCentric.org.