Gardening without pesticides

Gardening without pesticides

The Golden Rules of Ecological Gardening

It was long believed that the best way to deal with problems in the garden was to regularly spray pesticides to control unwanted pests. Over time, it was realized that this was not sustainable in the long term because it disrupted the balance of the environment and posed risks to human health. Rather, we are now trying to adapt our cultivation methods to support the health and vitality of plants so that they can withstand various stresses.

In fact, the best way to prevent problems in the garden is to first choose resistant plants adapted to the conditions of the environment and then to give them the appropriate care. In this context, pesticides are used only as a last resort when all other methods have failed.

Here are twelve rules to follow to get a beautiful garden without pesticides.

1. Place the right plant in the right place

A plant that requires shade and fresh soil will be much more susceptible to disease and pests if you plant it in direct sunlight in dry soil. It is therefore important to choose plants that are well suited to your growing conditions.

In most cases, it is better to move a plant that is obviously not in the right place than to try to keep it healthy by using pesticides.

2. Focus on plants that are resistant to pests and diseases

Even under good growing conditions, some plants remain particularly susceptible to pests and diseases. Unless you are willing to put in a lot of time and effort to keep them beautiful and healthy, the best solution is to replace them with more robust plants. The garden centers offer resistant cultivars in most types: phlox and monardes less vulnerable to white or powdery mildew, decorative crabappers more resistant to scab, roses free from black spot, etc.

3. Create a diverse environment

In a natural ecosystem, a multitude of organisms live in interdependence. In this diverse environment, populations of prey and predators tend to balance. To imitate this natural dynamic, several families, genera and plant species must be planted in order to attract a large number of living organisms that will interrelate.

Thus, it is better to plant a hedge composed of different shrubs than a wall of thuja or to arrange a massif of shrubs, perennials and bulbous plants that a rose garden.

If you have space and want a bit of shade, opt for an environment consisting of several strata of vegetation. An arrangement comprising a few trees, under which you plan shrubs and perennials adapted to the shady environment, will project a beneficial shade while welcoming a multitude of living organisms.

4. Attract natural predators

In order to attract natural predators (insects, mites, birds …), it is essential to choose the right plants. For example, several plants attractive to beneficial insects belong to the families of carrots (Apiaceae), mustard (Brassicaceae), mint (Lamiaceae) and daisy (Asteraceae). Many of them can be installed gracefully in landscaping.

Also make sure to have continually flowering plants and plant perennials, trees and shrubs that produce seeds and fruits that attract birds. Do not forget to introduce some conifers, as they serve as shelters for wildlife during the winter.

5. Amend the soil with compost

Compost is both an amendment and a fertilizer par excellence in the garden: it inoculates the soil in microorganisms, it serves as shelter and food for the latter, it improves the structure of the soil, it balances the pH and It provides essential nutrients to plants. With the exception of plants that thrive in poor soil, most plants benefit from compost.

As these elements are released gradually, plants benefit from a constant and regular source of food. On the other hand, there is growing evidence that plants that are fed with compost are more resistant to disease.

6. Fertilize with natural fertilizers

In an ecological fertilization program, natural fertilizers serve as complement to compost. They may be of organic origin (residues of plants or animals) or mineral (crushed rocks).

These fertilizers have not undergone any chemical transformation. To release their nutrients, most natural fertilizers must be degraded by living soil organisms. Thus, in addition to feeding the plants, they stimulate the biological life of the soil. Another advantage of this method of fertilizer degradation is to limit the risks of leaching and burning of the roots.

Natural fertilizers are particularly suitable in the following situations:

  • When the results of the soil analysis indicate a mineral deficiency
  • To restore a plant that has undergone great stress (disease, pests, drought, size of rejuvenation, transplant)
  • For plants grown in pots or containers

7. Make more use of mulch

A mulch keeps the soil moist and cool during the summer, reduces weed growth and, by incorporating with the soil, increases the water and nutrient retention capacity of the soil.

Mulches are well suited for use with trees, shrubs and perennials.

However, alpine plants and soil coverings that require well-drained soil can rot under a thick layer of organic mulch. It is therefore best to use a small gravel mulch around this type of plant.

8. Water deeply during periods of prolonged drought

A plant well adapted to its growth medium should not need to be watered outside periods of prolonged drought. However, newly planted plants must not run out of water during their establishment period. Once well established, most of them fill their needs with natural rainfall.

Plants that need water should be watered deep. Avoid wetting the foliage as much as possible, as moisture promotes the development of fungal diseases.

9. Prune trees and shrubs appropriately

The main purpose of pruning is to keep plants healthy. Dead, diseased or damaged branches should be removed as soon as possible.

In addition, sizes that aim to thin the antlers of dense trees and shrubs promote better penetration of air and light, making them less susceptible to pests and diseases.

For more information, please see our leaflet on the size of trees and ornamental shrubs .

10. Eliminate sources of infestation

It is possible to prevent or at least mitigate certain problems by eliminating outbreaks of infestation. For example :

  • By disinfecting your tools regularly to remove bacteria, viruses or fungus spores that are transmitted from one plant to another;
  • Eliminating plant debris infected with disease or infested with pests;
  • By cutting unwanted herbs before they produce seeds.

For more information, see the Horticultural Notebook, Diseases, Pests and Undesirable Plants section .


11. Keep an eye on your plants

Obviously, a well maintained garden is not immune to all problems. For this reason, attention must be paid to visible anomalies on the plants: leaves that have been smeared, stained or discolored, curled shoots, galls and discolorations on branches, etc.

It is important to be aware of the first symptoms caused by a pest, disease or poor growth conditions: these signs give you the chance to react before the problems become uncontrollable. Moreover, most control methods are effective when initiated at the onset of an infestation.

Finally, the more you know about the specific needs of your plants and the problems that may affect them, the more you will be able to react quickly.

12. Use low impact pesticides as a last resort

A plant looks bad. What to do? Begin by carefully examining it to identify the cause of the problem. If you do not detect any particular pests or diseases, make sure that the plant is not suffering from poor growth conditions (lack of light, dryness, excess or deficiency of nutrients, pH too high or too low, excessive cold , Burning caused by wind, etc.). If a pest or disease is involved, first assess the extent of theproblem and then decide whether it is appropriate to apply a control method. Strong plants that grow under good growth conditions can tolerate the presence of a few insects or pathogens.

If you decide to intervene, first try to control the invaders using cultural, physical, mechanical and biological methods. If these measures do not produce the desired results and the use of pesticides is inevitable, choose low-impact products. They are low in toxicity, short or long term, for human health and the environment. They degrade rapidly and most of them destroy pests with minimal effects on beneficial organisms.

Read and follow the manufacturer’s instructions carefully before performing any treatment. Pay particular attention to dosages, application procedures, safety instructions and waiting times between treatments. Finally, follow up after treatment and adjust your cultivation methods afterwards.

The use of pesticides is governed by the federal Pest Management Regulatory Agency (Pest Management Regulatory Agency), the Provincial Pesticide Management Code, and municipal by-laws such as Regulation 04-041 on the Use of Pesticides in City of Montreal. Before using a product, consult your local authority.

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