To ensure the health of his or her ornamental plants and vegetables, the ecologically responsible gardener must make some important choices. The tendency to want the prettiest flowers, the greenest grass and the biggest tomatoes can lead to bad decisions when the time comes to enrich the soil with fertilizers. Let’s look at the various types of fertilizers available and the environmental impact of each.
Five stars for compost!
Compost domestique © cc flickr (E. v. Muench)
The best fertilizer from an environmental standpoint is the compost you make at home. It is a locally sourced product that has not been wrapped in plastic or transported long distances, as is the case of commercial composts and fertilizers.
Furthermore, domestic compost is made from renewable resources — that is, our compostable waste — which is not the case of synthetic fertilizers. These are made from minerals and gases that are transformed chemically; the phosphorous and potassium in them come from rocks that are crushed and treated with substances to make them more soluble. Nitrogen is made from ammonia (NH3), produced by combining nitrogen(N) from the air and hydrogen (H) from natural gas, an energy-intensive process.
A few tips
- Reduce your use of fertilizer to a minimum
In most cases, it is pointless to apply large amounts of fertilizer each year. Incorporating 20% compost into the soil during planting will provide sufficient nutrients to meet the needs of most plants for their first year, and even for the following two years. Afterwards, simply add 2.5–5 cm of compost every two or three years to maintain the soil’s fertility.
Compost marin (Bio Nord) © Jardin botanique de Montréal (Jean-Pierre Parent)
Use compost and organic fertilizers instead of synthetic fertilizers
When compost is not enough to meet plants’ needs, it is preferable to use natural fertilizers. A good portion of their nutrients come from agricultural byproducts, thus giving them a second life (plant and animal waste). For their nutrients to be released, most natural fertilizers (as opposed to synthetic ones) must be broken down by organisms in the soil. Therefore, in addition to providing plants with nutrients, they stimulate biological activity in the soil.
As you can see, it doesn’t take much to change your habits when it comes to fertilizers. You will make better decisions by choosing the most natural ingredients possible, with a low impact on the environment at every stage of their production. Using compost will also reduce your household waste!