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Companion Planting and Composting

Companion Planting is not the concept of matching plants to make a more visually appealing garden. It is a historically and scientifically proven strategy to minimize disease and maximize resource use and symbiotic relationships.

“Three Sisters”
Historical Companion Planting

Named used by the Iroquois for corn, squash and beans that were traditionally grown together for their symbiotic characteristics. Tall sturdy stalks of corn would grow first, creating support for the beans which would wind around the stalk, producing available nitrogen for the others as it grew, finally the squash, the lowest plant would provide ground cover to protect the soil, eliminate room for weed, and its larger leafy matter serves as mulch.

For centuries, farmers and gardens alike have noticed how certain combinations of plants achieve results and harvests far greater than that of what was achieved with the plants separated.
These anecdotes have been reinforced through scientific research that has found certain relationships are. They are:

  • Symbiotic nitrogen fixation

    Leguminous plants have developed a mutual relationship with specific soil bacteria. These bacteria attach at the roots of the plant and transfer nitrogen from a form that is unavailable to a viable form for plant use. In return, the bacteria receive nourishment from the legumes.

  • Trap Crops

    Plot can be designed so that they include plants that act as attractants for pests of the more desired crop. It essentially diverts the pest from the crop you want to harvest to a less desired crop.

  • Biochemical pest suppression

    Certain plants secrete chemicals that deter pests from entering the area. For example, marigolds are planted at the perimeter of gardens to remove flying pests from the area.

  • Habitat creation for beneficials

    Plants that attract beneficial insects to the garden can increase both the health of the plants and the biodiversity of the system

  • Physical spatial interactions

    For example, Tall, sun-loving plants can be grown with shade-loving low plants, as this will maximize the use of space in the garden, as well as acting as ground cover so that there does not exist a niche for weeds to grow.

  • Security through diversity

    This is a general concept that is completely opposite of the system that we see today in industrial agriculture that chooses to produce crops in monocropped rows acre upon acre. This relationship is that a diverse habitat is less likely to be subject to disease or pest, because there exists sufficient niches for each organism, pest and non-pest alike, and an losses are kept at reasonable levels.

How to make companion planting work for you

  • Be an attentive gardener;
  • Experiment with combinations of plants and record your success;
  • Remember each garden has it particular niches and needs and cater to them; and
  • Good luck!


Composting is the process of converting organic material (grass clippings, coffee grinds, eggshells, to name a few) into a soil-like substance called humus. It is an easy process that anyone can do in their home or backyard to help reduce waste as well as improve the health of their garden.

The Composting Council of Canada has compiled a list of do’s and don’ts for backyard gardening:

From the Garden...

Leaves (chopped - to speed their breakdown)
Grass (not wet)
Plants & Weeds (without ripe seeds)
Old potting soil
Soft plant stems

From the Kitchen…

Fruit scraps
Vegetable trimmings
Egg shells (crushed)
Tea bags
Coffee grounds with filters
Shredded paper

DO NOT include...

Meat, fish and bones
Fats and oils
Dairy products
Pet waste
Cheese, meat or other sauces

Compost is not only an effective waste management solution; it is also an excellent source of plant nutrients. It increases beneficial micro organisms, nematodes and earthworm populations. Compost also improves soil structure. It loosens up hard clay and adds stability to sand. The high humus content acts as a sponge that is a water reservoir for garden plants. Furthermore, compost has the ability to neutralize garden soil. This in turn creates optimum growing conditions.

If you live in an apartment, and not have a backyard, don’t despair! Vermiculture (worm composting) is gaining popularity as an efficient alternative to backyard composting. A container (typically the size of a standard blue bin) is filled with soils and special worms capable of degrade organic waste with a perforated lid. Waste is added and the worms quickly eat the products and excrete castings. These castings are extremely rich in nutrients that are readily available to plants.

Across Canada there are several cities and municipalities that include compost pickup as one of their services; they include, Halifax NS, Olds AB, Ottawa ON and Toronto ON (both as a pilot projects). Many others promote backyard composting with subsidized bins available through the city and yard waste collected in the spring and fall.

What can you do?

  • Contact your local municipality and ask them about the ways they promote composting in your area.

  • Start a vermiculture compost bin in your office, it’s a create way to reduce waste in the workplace!

  • Use your compost to grow veggies in the summer, they will be healthy plants from all the organic matter in the soil, and eating the fruits of your labour will increase your intake of fresh produce, and help reduce the importance on imported agricultural products


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