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revised October 01, 2013

Maintaining Your Lawn


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  • Mow high.
    Cutting your grass to 6-8 cm (2.5-3 inches) will help it develop a deep, extensive root system, grow thicker, and hold more moisture.

  • Cut your grass when it's dry.
    Sharpen your mower blade in the spring and keep it sharp to avoid tearing the grass. Grass can recover more quickly and easily from one clean cut than from many tears.

  • Leave the lawn clippings on your lawn.
    Clippings provide a great source of slowly released nitrogen for the grass and humus for the soil.

    Leave the grass clippings after mowing except under wet spring conditions. During this time it's best to remove thick layers of clippings (over 1/2 cm thick) to avoid smothering the grass.



  • Water in the early morning.
    Early morning is the best time to water your lawn and garden as less moisture is lost through evaporation and wind.

    Watering in the evening leaves the grass wet for a longer period of time, increasing the risk of disease. Grass growing near large trees may need more frequent watering, since the tree roots may use much of the soil water.

    A healthy lawn can survive several weeks in a dormant state. Visit WaterSmart Peel for more information on smart watering.

  • Check your lawn's moisture level often.
    During extended hot dry periods, your lawn may wilt, turn brown, and become dormant. But it will green again when regular moisture conditions return. Check your lawn regularly to detect any pests or other problems early.

  • Replace Grass.
    Plant beautiful drought tolerant gardens to reduce watering and the needs for pesticides and herbicides. For more information visit Water Wise Gardens.




Compost is a great fertilizer: it not only adds organic matter to your lawn, but also provides nutrients plants need to grow.

You can apply compost at any time. Mix it into the soil before seeding or laying sod, or spread it in a thin layer raked over the existing lawn.

Commercial Fertilizers

Commercial fertilizers usually contain three major nutrients:

  1. nitrogen (N) to promote leaf growth
  2. phosphorus (P) for root growth; and
  3. potassium (K), which is essential for stress resistance.

The three numbers on the packaging represent the proportions of these nutrients. For example, a 21-7-7 formulation contains 21 percent nitrogen, 7 percent phosphorus, and 7 percent potassium.

Slow-Release Fertilizers Are Best

Fertilizers with a slow-release form of nitrogen are better because they feed the grass and plants more evenly. There is also less risk that excess fertilizer will trickle away from the plants' roots.

Generally speaking, a good ratio for a lawn fertilizer is 4-1-2. (The numbers can be higher but should stay in that proportion; for example, 8-2-4).

Rates and Timing

When - and how much - you fertilize your garden or lawn depends not only on the type of soil and grass you have, but also on site and weather conditions. In general you should apply less fertillizer in the spring and early summer than in early and late fall.

Have your soil analyzed every few years by a professional laboratory. This will tell you not only what type and rate of fertilizer to use, but also if the pH of your soil is adequate.

Beware of combined fertilizer-herbicide products (weed and feed type). You should only consider these if your lawn has a widespread weed problem that can't be dealt with through other weed control methods (e.g., hand digging or spot-spraying).


Over-seeding and Replacing Sod

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Healthy lawns recover from damage and fill in thinned areas caused by insects or other damage. If bare patches don't fill in quickly, weeds can invade these open spaces.


Over-seeding your lawn during the early fall will make the grass stay dense. You can top-dress with compost or topsoil at the same time. Depending on the state of your lawn, you can use up to twice the seeding rate recommended for your grass type. Over-seeding is very important for lawns in shady areas.

Replacing Sod

Plant beautiful drought tolerant gardens to reduce watering and the needs for pesticides and herbicides. For more information visit Water Wise Gardens.

To replace sod:

  1. Cut out the dead or damaged area to about 2 cm deep.
  2. Rake the soil and add some compost or fertilizer.
  3. Put the new piece of sod in, stepping on it or rolling it. Keep the new seed or sod well watered until the new grass is established.



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Aerating your lawn lets water flow more easily to the plant roots, allowing them to grow more easily through the soil.

Aeration is best done in the early fall before overseeding and topdressing. Don't roll the lawn in spring as this will cause the soil to compact.

Signs That You Need to Aerate

You may need to aerate your lawn if:

  1. The ground is hard and compacted.
  2. Thatch (the layer of dead material between the grass blades and the soil) is building up, and
  3. Water doesn't penetrate well when you irrigate.

Mechanical Aerators

There are two types of mechanical aerators:

  1. a solid-tined machine that drives spikes into the ground
  2. a core machine that removes small plugs of soil

You can also use sandals and shoes equipped with spikes to aerate if your lawn is small.



Thatch is a mixture of dead grass and roots and other organic matter found between the green matter and soil surface.


Source: Zac Reicher, Associate Professor/Turfgrass Extension Specialist
Purdue University

In a healthy lawn, insects, earthworms, beneficial fungi, and other micro-organisms break down thatch and aerate the soil. Too much water or nitrogen fertilizer, compacted soil, or the heavy use of insecticides and fungicides reduce the populations of soil organisms needed to keep thatch levels down.

Thatch that is more than 1 cm (1/2 inch) thick can prevent water, air, and nutrients from getting to the plants' roots. It can harbour harmful insects and diseases and cause localized dry spots. When thatch dries out, it repels water and can be very difficult to wet again.

Remove excess thatch with a heavy rake or de-thatching equipment, and then over-seed.


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Revised: October 01, 2013


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