Gardens, lawns and ecological maintenance

Pesticides are prohibited at all times

See the information sheets on ecological maintenance on our website. In the event of a major infestation, contact the Permits and inspection Service for a permit.

What is my primary motivation for composting?

  • Reducing my waste and joining the growing movement of "responsible citizens seeking a more ecological lifestyle"
  • Producing my own economical, ecological soil conditioner for my flowerbeds, lawn and vegetable garden (or as a gift, if I don’t have flowerbeds, a lawn or vegetable garden).
  • A combination of the two, but in what proportion?

How much organic matter do I produce daily?

  • I am a vegetarian and every day, I eat a lot of different fruits and vegetables, including watermelon, pineapple, pumpkin, squash and corn, all foods that generate considerable waste.
  • I eat enough fruits and vegetables to generate, on average, the equivalent of a 750 g yogurt container
  • There are just two of us, so we generate little organic waste.

A balance of time/energy/personal needs: a guarantee of long-term success

Your answer to these two questions will determine the amount of time and energy you will choose to spend on composting. Remember that nature does things well, and on its own…

If you want to compost for the sole purpose of reducing the volume of waste you produce, even if results could take up to two years: add your peels every 3 to 4 days and forget about the compost, doing just enough maintenance to avoid odours.

If you are composting in order to harvest compost once or twice a year, you would do well to monitor its development, to find the perfect mix, to water and stir it, and to add everything you haven’t consumed, down to the last seed: more daily maintenance required, with peak periods in the spring and fall.

In either case, you would do well to start off slowly, working this activity into your daily routine.

You might also decide not to put everything in the composter from one day to the next. Remember that, until now, all of this organic matter had gone out with the garbage. Take the time to adjust to this new approach, to work it into your daily routine, and most importantly, to balance the contents of your compost! Before long, questions and uncertainty will give way to expertise and pride! Turn your first harvest into a celebration: in the spring or fall, bring together the ones who contributed to the production of your homegrown compost!

The ABCs of domestic composting

What is compost?

It is a biologically stable and hygienic soil conditioner, rich in humus, resulting from the biochemical conversion of biodegradable organic waste decomposed by microorganisms and aerobic organisms.

What is a composter?

Quite simply, it is a unit that accelerates and controls the work of nature. In nature, everything decomposes, layer by layer. The same thing occurs in the composter.

How to install the Earth Machine? 

  • Tip 1: assemble the composter upside down. This will make it easier for you to see the tabs and ensure that they are lined up with the slots before assembling.

  • Tip 2: when you turn the sod or loosen the soil to allow the microorganisms to move up into the composter, remove approximately 6 inches of sod around the composter and replace it with mulch. This will avoid the growth of tall grass (enriched by the organic matter) that is difficult to mow around the composter. To start: build a nest of twigs and branches to a height of 5 inches, then add soil and dead leaves.The composter is now ready to receive your organic matter.

How to get good results?

It’s all a matter of balance: Matter -> Water, humidity <-> Air, oxygen <-> Micro-organisms

Tip: 1 part green for 2 parts brown matter.

Nitrogen-rich materials
(green - humid materials)
Carbon-rich materials
(brown – dry materials)
Materials not to be composted
(or in very moderate amounts)
Fruit leftovers - raw, cooked
Vegetable leftovers - raw, cooked
Cooking water
Fresh sod shavings
Mature manure
Crushed egg shells
Dry leaves
Newsprint (if no leaves)
Straw, hay
Coffee grounds, coffee filters
Tea bags
Paper towels
Pasta, bread, rice
Walnut shells
Natural fabrics
Hair, nails
Bird litter, feathers
Animal hair
Dead plants and dried flowers
Weed seeds
Wood ashes
Slacked lime
BBQ briquettes
Meat and fish
Oil and fat
Dairy products
Human and animal excrement
Vacuum cleaner dust
Rhubarb leaves
Treated wood
Plants or sick foliage
Large amount of soaked material in one layer

How to collect the compost?

To maximize the production and use of compost:

  • In the fall: Remove the composter and move it closer to the house; cover the uncovered heap with a plastic tarp and let it ripen throughout the winter. Stirred a few times as soon as it thaws, this compost will be ready to use early in the spring (April).

  • In the spring (early April): Return the composter to its original location. Turn over compost stacked near the house all winter, alternating with brown matter, and pile it up next to the composter that has been returned to the yard. Turned over once or twice and covered with a plastic tarp, this compost will be ready in 3 months (end of June). The empty composter can then be filled normally with fresh matter from the kitchen as of April, and the cycle can start anew.

  • For sporadic use: Simply open the door and serve yourself.

How to use the compost?

In the spring, you can spread ripe compost on flowerbeds, the lawn, the vegetable garden. You can mix it with repotting soil for indoor plants. As a rule, it is preferable to spread young compost late in the fall: it will continue to ripen on the ground and will be perfect for use on most plants in the spring.

Where to find more information?

Lawn treatment firms solicit your business for the maintenance of your property. A word of caution: be wary of their "magic" formulas! Despite municipal bylaws prohibiting the use of pesticides outside the house, some companies are suspected of still using them illegally and without your consent!

Before settling on a company:

  • Ask yourself what you expect and draw up a list of the services you would like (fertilization, aeration, compost application, soil testing, nematode treatment, etc.)
  • If you don’t know the contractor soliciting your business, don’t hesitate to ask for references.
  • Compare prices with other companies (bearing in mind that the highest price does not necessarily guarantee the best service).
  • Ask for written information on the products offered, and require detailed invoices to ensure that these are the products being used.

Ensure that the contractor you select uses 100% natural fertilizer (almost always granular) that presents no danger to health or the environment, and whose N-P-K formula is less than 10 (ex.: 44-2 fertilizer by Acti-sol, whose figures are all lower than 10).

Furthermore, when you hire a contractor to apply fertilizer, low-impact pesticides or any other product on your lawn, ensure that the company is registered with the Town. Bear in mind, however, that being registered with the Town does not guarantee that the contractor is competent; he must have the legal permits needed to apply his products, in keeping with provincial laws. These rules also apply to companies that maintain hedges, trees and flowerbeds. Contractors who only do mechanical maintenance work (mowing, dethatching, manual weed removal, etc.) are not required to be registered with the Town.

Remember that, in the long run, adopting good lawn gardening methods (aeration, compost application, top soil application, dethatching, mowing high, etc.) is a winning formula, and that the application of various control products (ecological or other) must only be considered as a last resort. Because of this, companies whose services were once limited solely to lawn treatments (pesticides and fertilizers), now offer a range of services including manual weed removal, soil testing, etc.

In fact, some companies provide very good follow-up services dispensed by competent employees capable of diagnosing various problems to which your lawn may fall prey. Obviously, it would be wrong to lump all contractors together, but some have recently made considerable efforts to offer ecological maintenance services.

To find out if a company has recently been convicted of an offense, contact the eco-consultant at the Public Works Department by calling 450 621-3500, ext. 3305.

For additional information:

Putting in a new lawn: seed or sod?

After building a new home or following a severe infestation of grubs, you have a number of options for putting in a new lawn. Regardless of the one you choose, you should know that, to a great extent, the results will depend on your soil (its texture, organic composition, thickness). And while it may be more expensive to buy a sufficient quantity of high-quality topsoil (minimum 6-inch layer in the case of a new construction), you will come out ahead in the long run, as your annual lawn maintenance costs will be reduced.


Sod is a fast but expensive solution that requires less maintenance than seeding. Furthermore, between early June and mid-August, temperatures do not foster the germination of grass seeds (over 25ºC, dry conditions).

While putting in sod is especially practical if you have young children, as you don’t want them playing in dirt all summer long, it does carry disadvantages other than its high cost.

Firstly, since sod consists mainly of Kentucky blue grass, it is hardly varied. As a result, over time (after approximately 3-4 years), it becomes more vulnerable to pests, unless it has been properly maintained. It is also important to know that sod is grown on agricultural land where it is heavily subjected to pesticides. In fact, when a large quantity of sod is delivered to a neighbourhood, it is not unusual to detect a strong odour of pesticides. Consequently, you must take protective measures when handling the sod (wear long sleeves, pants and gloves). You should also wait a few days before allowing children (or pets) to play on it.

Another important consideration: sod can require a significant amount of water if put in during hot, dry weather. To save water, time sod’s installation with the weather. The planet will be a better place for it.

If you still choose the sod option, you can enhance the contents of your lawn over time, by adding other types of seeds every year. Simply adopt good gardening methods and overseed every fall, introducing new grass varieties to the existing one.

Conventional seeding

Seeding should be done between mid-May and early June and between mid-August and mid-September when temperatures foster the germination of the seeds. However, these periods can vary according to weather conditions, and every effort should be made to coordinate seeding with cool, rainy weather.

Seeding points to bear in mind:

  • Begin by levelling the ground well.
  • Spread a layer of high-quality topsoil rich in organic matter (adding compost is suggested)
  • Choose an ecological mix of lawn seeds that includes a percentage of fescue, perennial ryegrass, and Kentucky blue grass (depending on sun exposure and your tastes). Don’t hesitate to ask nursery personnel for advice.
  • If you opt for a mix that contains white clover, it is recommended that you seed in the spring rather than the fall, to allow it to take well.
  • Spread approximately 1.5 to 2.5 kg of seed per 100 m2 (if there is too much seed, the competition among the seeds will eventually be too strong, and results may be disappointing).
  • Cover the seeds with a thin layer of topsoil (a few millimetres).

Hydraulic seeding

There is a third, lesser-known option: hydraulic seeding. Offered by some companies, this type of seeding consists in mixing grass seeds with water and projecting it through a pump or hose. This method is more costly than conventional seeding, but is often more effective, especially in the case of sloped surfaces or large areas. It is also faster.

This can be explained in part by the fact that the seeds, which have soaked in water, will germinate more quickly. In addition, the use of mulch (paper fibres, shredded wood, hay or straw) in the mix or applied afterwards, will keep the surface moist longer, and keep birds away from the seeds.

In addition, the seed mix can be personalized to your preferences.

Long-term lawn maintenance

First, you have to know that a healthy lawn (diverse and pesticide-free), with longer roots, is better able to withstand the attacks of more pests than a weakened lawn. As a result, prevention becomes your best weapon against severe infestations, regardless of the type of pest. What’s more, a healthy lawn is much more capable of withstanding the full range of environmental stresses, such as drought, heat, cold, and trampling.

For your lawn to grow well, the temperature must be cool and humid, and the soil must be rich and light. When establishing a new lawn, it is the soil that supports the growth of the grass, which is why it must be adequate if you wish to obtain good results.

If you have adopted ecological maintenance habits in recent years, but your lawn’s appearance leaves much to be desired, the problem most likely lies with the soil’s composition.

In Rosemère, many lots are clayey, resulting in highly compact soil. This is bad for grass roots. To counter the problem, aerate the soil annually, then add a thin layer of topsoil (with aged compost), and overseed, ideally at the end of the summer (mid-August to mid-September), otherwise in the spring. On the other hand, newer neighbourhoods located in the eastern part of the town are on higher ground, and the soil is sandy and poor, which also presents a problem for lawns. Sandy soils should be enriched through the annual addition of topsoil (with 1 cm of aged compost), followed by overseeding.

As for other good habits to adopt

  • Watering
    You should water in depth but less often, forcing roots to grow deeper to reach the water. One or two waterings per week are sufficient. If the water penetrates well, the results should be quite good!

  • Mowing
    The grass should be no shorter than 7.5 cm (3 inches), except for the first cut in the spring, when you can go a little lower. Bear in mind that the length of the roots is proportionate to the length of the grass. Also ensure that the blades of your mower are well sharpened.

  • Grasscycling
    Leaving grass clippings on the ground cuts the need for fertilizer by 5% to 50%, which is hardly negligible. Another way of reducing green waste at home is to enrich your lawn, using tree leaves as fertilizer. In the fall, simply mow over the leaves to shred them.

  • Reducing thatch
    Thatch is nothing more than dead grass that has not decomposed and has accumulated on the surface of the soil. You shouldn’t have any if you’ve adopted ecological lawn maintenance habits. Thatch is often a problem of poor decomposition related to the use of chemical fertilizers or pesticides, which kill off the best possible decomposers, earthworms. On the other hand, thatch can also accumulate in soils that are very poor in organic matter or overly compact. In both cases, adding aged compost could improve the situation by activating decomposition by microorganisms.

Alternatives to a lawn

There are instances when conditions are so difficult for grass seeds that the establishment of a healthy lawn is either virtually impossible or too expensive over the long term.This could be a sign that you should stop fighting nature and opt for vegetation that is better suited to the environment and will do well. Rosemère, for example, has many hills and slopes. Properties are seldom level, and often slope towards the ditch in front of houses. Water drains quickly on these inclines, making it particularly difficult from grass to take. However, flowerbeds and rock gardens, including landscaping arrangements for drought conditions, often yield much better results (thyme, gypsophila repens, sedum repens, Irish moss, pink corepopsis, arabis, ajuga, etc.)

On the other hand, there is sometimes so much shade under a tree that grass is unable to grow, which is hardly surprising when you consider that grass is a form of vegetation that thrives in the sun. Compounding the problem is the fact that the quantity of leaves that fall in autumn is sufficient to suffocate any lawn. Putting in shade-friendly vegetation (hostas, ferns), ground covers (vinca minor, moss) and inert materials (flagstones, mulches, etc) are effective alternatives to grass and effectively showcase Rosemère’s many magnificent trees.

In areas with intermediate sun (slight shade), opt for creeping phlox, pachysandra, lysimachia nummularia, dead nettle, birdsfoot trefoil, etc.

Replanning your garden might also provide a welcome opportunity for you to create a cosy corner, with a swing, lanterns, and water garden where you wouldn’t have any grass to mow… Be creative!

For additional information on the establishment or maintenance of a lawn, please contact the Town’s eco-consultant, at 450 621-3500, ext. 3305, or see the following list of reference books and websites:

  • Fortier Serge, 2005. Alternatives écologiques à la pelouse. Les Éditions Serge Fortier Inc, Qc. 327 pages.
  • Lévesque Micheline, 2008. L’écopelouse – Pour une pelouse vraiment écologique. Bertrand Dumont Éditeur Inc. 192 pages.
  • Lévesque Micheline, 2005. Le guide complet des pesticides à faible impact et autres solutions naturelles. Isabelle Quentin Éditeur, Ville Lasalle, Qc. 214 pages.
  • Rubin, Carol, 2002. How To Get Your Lawn Off Grass, A North American Guide to Turning Off the Water Tap and Going Native. Harbour Publisher, 208 pages.
  • Rubin, Carol, 2003. How To Get Your Lawn and Garden Off Drugs: A Basic Guide to Pesticide-free Gardening in North America. Harbour Publisher, 144 pages.
  • Smeesters E., Daniel A., & Djotni A., 2005. Solutions écologiques en horticulture. Éditions Broquet, St-Constant, Qc. 198 pages.
  • Website of the Montréal Botanical Garden: Lawn and Ground Covers
  • Website of the Montréal Botanical Garden
  • Hydraulic seeding website

Ants are social little insects that generally play a useful role in nature and whose presence is not necessarily problematic. Since there are many trees in Rosemère, ants are quite present and active here for much of the season.

In your grass, they can cause a few problems as they tend to build small nests here and there throughout the lawn. On the other hand, they aerate the soil by excavating galleries, clean away small debris and effectively prey on a number of garden pests, including white grubs. While we should learn to appreciate and tolerate them, there are a few things we can do to make our lawn a bit less attractive to them:

  • The regular use of vegetal compost enhances the moisture and organic matter in the soil; it’s a good way of enriching the lawn and disrupting the work of ants.

  • Spreading a thin layer of black earth on sandy soil will reduce the proportion of sand, making it harder for ants to build their tunnels.

Carpenter ants tend to be more worrisome though they are rarely a source of major problems. Carpenter ants build their nest in damp or rotting wood, tunnelling deeply. They are often visible near old tree stumps, fences with rotting wood or close to cords of wood. These ants are quite active; they forage for food wherever they can find it, which is why they visit our houses every spring. If they happen to come across damp wood while visiting, chances are they could settle in. The best way to avoid this situation is to watch for the infiltration of water (window sills, basements, roof…) and to replace any wood that remains damp. As a rule, ants do not attack sound wood, but they will make the most of pre-existing problems.

Although they tend to be more active at night, some clues could point to the presence of an ant colony in your home:

  • Presence of tiny piles of sawdust in the house.
  • Ants active in the house during winter, particularly if they are winged.

To get rid of a colony of carpenter ants, you have to find the main nest and destroy it. Unfortunately, it is not always easy to locate. In some cases, it is outside the house while satellite nests are indoors. If the nest found inside is easily accessible, simply use a vacuum cleaner (don’t forget to empty the bag and leave it outside…) or boiling water to kill the ants.

A number of so-called "low impact" products can be used if you have ants in the house. Borax-­based products (approximately 5% concentration) are used as bait to kill the colony. Foraging ants contaminate the queen by sharing the poisoned food in their second stomach with the rest of the colony through a process known as trophallaxis.

To eliminate outdoor nests, you can install an ant trap at each corner of the house, adding a borax-based product (ex.: "Attack" by Safer’s) as bait. Simply pour the sweet borax mix in aluminium plates or in a trap designed for this purpose ("Ant Pro"), which can be ordered online from However, the mix must be renewed daily, as it tends to dry out and must remain liquid, if the ants are to drink it.

You can also sprinkle diatomaceous earth ("Insectigone" by Chemfree) where ants are likely to enter or pass. The silica naturally contained in this powder acts mechanically by dehydrating the ants and causing their death. Sold in most good hardware stores or garden centres, these products must be used as directed, and though they are low impact, they should be kept out of the reach of children and pets.

Still, it is important to remember that ants can be useful when they are outside, and the excessive use of diatomaceous earth could prove harmful to other useful insects living in your garden, including the invaluable pollinators.

Whether you are dealing with ants in your lawn or carpenter ants, you must prevent them from entering your home, where they are not welcome. First, you would do well to search for, and seal cracks and holes through which they can enter. In addition, discard aphid-infested houseplants and clean food crumbs from your cupboards, as these could attract them.

Beware of the "good" exterminator who returns every year… If he’s back, it’s because your problem hasn’t been settled! In fact, resorting to the services of an exterminator who uses pesticides is only justified if a colony has settled inside the frame of your home. A conscientious company will also seek a way to keep the ants from entering the house, offering to caulk doors and windows and proposing various methods to seal the different openings.

Resorting to an insect specialist such as an entomologist can often prove to be a better long-term approach. On the other hand, if you must call in an exterminator who uses pesticides, remember that he cannot use them outside the house, unless you have obtained a temporary permit from the Town’s Public Works Department. For additional information, contact the Town’s eco-consultant, at 450 621-3500, ext. 3305.

For additional information:

  • Boucher Stéphanie, 2006. Les insectes de nos jardins. Éditions Broquet, St-Constant, Qc. 208 pages.
  • Lévesque Micheline, 2005. Le guide complet des pesticides à faible impact et autres solutions naturelles. Isabelle Quentin Éditeur, Ville Lasalle, Qc. 214 pages.
  • Very complete website of the Montréal Insectarium

In today’s world, the cost of having a perfect "weed-free” lawn, both economically and environmentally, is very high, which is why it is so important for you to determine your level of weed tolerance before defining a plan of action.

At the outset, it is important to know that it is difficult for weeds to take hold in a very dense lawn of adequate length. In fact, a lawn that is suddenly overrun with weeds is a lawn that has been weakened for a variety of reasons (poor gardening conditions, soil that is depleted, acidic or overly compact, etc.). Applying good gardening methods will help you counter the problem.

Whether it’s dandelions, plantain, crabgrass, strawberry plants or Creeping Charlie, weeds often take over where grass is already struggling. In Rosemère, the soil is heavy and compact in a number of places, due mainly to its high clay content. These conditions tend to favour the growth of weeds with large, pivoting roots like dandelions and plantain, as well as the proliferation of Creeping Charlie. Others, like strawberry plants, do particularly well in depleted or acidic soil. In these cases, fertilize well using natural products and add lime to restore the soil’s pH balance. A soil test (provided by many gardening centres) can help you opt for the most effective solution.

Avoid keeping lawn sections damaged by grubs from being exposed to weeds too long. In fact, if you wait too long to reseed these patches, annual weeds will take root, including the highly allergenic ragweed or crabgrass, which are very hard to eliminate. These weeds must be ripped out as quickly as possible in the spring, before they have a chance to bloom or produce seeds.

A bit of advice: if you buy a low-impact herbicide treatment such as TOPGUN or ECOCLEAR, available at garden centres, use the proper concentrations and avoid putting too much on the lawn, since they often eliminate all vegetation, without distinction. These products are better suited to the elimination of weeds that grow between paving stones or close to the asphalt.

Ripping weeds out by hand remains the most effective as well as the most ecological way of ridding yourself of these unwanted plants. A tip: after removing the weed, fill the hole with a mixture of earth and lawn seeds. That way, the empty space won’t invite another intruder. For your information, a number of contractors now offer this ecological maintenance service.

About white clover:

White clover cohabitates quite well with grass. However, it does tend to take over in dry or depleted soil. To maintain a fine balance between the two, adopt good gardening practices. Clover requires little maintenance and remains green during heatwaves. It will take better if seeding is done in the spring. However, it is more sensitive to freezing when not covered with snow in winter.

About corn gluten meal:

Corn gluten meal keeps weed seeds from germinating (dandelion, plantain, crabgrass), but it is not a herbicide per se. Consequently, it does not affect the grass or other vegetation already in the lawn. It should be applied in the spring, when the lilacs start to bloom. However, if you are planning to re­seed your lawn, you must wait until the fall, since this product will also keep grass seeds from germinating. You can also apply corn gluten meal in early September. It is important to use it in moderation, especially if you have already fertilized, since it is high in nitrogen.

And what about herbicides?

Municipal bylaws prohibit the use of synthetic herbicides to suppress lawn weeds. The Québec Pesticides Management Code, which went into effect in April 2006, is also highly restrictive when it comes to the use of pesticides.

If your lawn maintenance contractor offers you a miracle cure for your weed product, be wary! Chances are it won’t make your dandelions curl up and die, unless of course, some chemical pesticides have been added to the mix. It happens more often than you might think!

Some new low-impact herbicides such as Sarritor (fungus that attacks plants), Fiesta (iron chelate also marketed under the name "Scott’s Weed B-Gone") and Organo Sol (containing citric and lactic acids), can also be offered by contractors but are not applied in a traditional fashion.

At this time, despite the constant marketing of new low-impact products, there is no truly effective selective ecological product (one that will eliminate weeds only). So, if you happen to detect the odour of chemical products in your neighbourhood, contact the eco-consultant at the Technical Services and Public Works Department, 450 621-3500, ext. 3305.

For additional information:

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