This site uses JavaScript. Please enable JavaScript in your Browser and reload the page to view the full site.

Lawn care


Plants need 16 essential nutrients to grow. Carbon, Oxygen, and Hydrogen are absorbed from the air and water while all the rest come from the soil. Most nutrients are used in very small amounts so they are generally available to plants from the natural breakdown of both organic material and mineral components in soil. Use organic fertilizer such as compost, to improve soil fertility.

Plants consume three nutrients from the soil in large quantities: Nitrogen, Phosphate and Potassium. These important nutrients are depleted by common gardening practices such as cutting down plants.

Fertilizers always have three numbers on their labels that refer to the amount of Nitrogen, Phosphate and Potassium available to the plant in the package.

Nitrogen (N)
The leaves, stems and roots need a large amount of Nitrogen for lush green growth. Nitrogen is easily lost from the garden by leaching with water or escaping from the soil as a gas.

Deficiency symptoms
There will be a uniform yellowing of the leaves that starts in the old leaves. The plant moves Nitrogen from the old leaves to make new leaves and tips. The stems will be thin and spindly.

Over abundance symptoms
The plant will have rapid bright to dark green lush growth. It will be weak because the cells are growing too quickly. The plant will be susceptible to insect and disease damage because of the weak cells. Nitrogen abundance also delays or reduces flowering and fruiting.

Phosphate (P)
Phosphate is needed for root growth, flowering, fruit and seed development.

Deficiency symptoms
The plant will have stunted growth and dark green leaves. The old leaves lower on the stem may become purplish between the veins. Delayed maturation, few flowers and poor seed development are further symptoms of deficiency.

Over abundance symptoms
Not normally a problem.

Potassium (K)
Potassium is needed for flower, fruit and leaf production. It increases the plant’s ability to withstand environmental stresses. It improves winter hardiness, heat and drought tolerance, resistance to fungal infections and insect damage. Potassium is found in abundance in the growing tips of plants because it activates enzymes, regulates the movement of fluids through the cells and plant. It is essential for plant growth.

Deficiency symptoms

Leaves yellow from the edges to the centre. Older leaves become mottled. Stems suddenly snap off.

Over abundance symptoms
It is best to apply Potassium in small quantities, or frequently if it is needed.

Organic fertilizers include compost, manure, and fish, bone or blood meal.

  • They improve the condition of the soil making it more porous, leading to better water drainage and water storage.
  • They improve the storage of all nutrients, reducing leaching into the waterways. They also supply micro-nutrients needed for plant growth, and feed the earthworms and other organisms that live in the soil.
  • Organic matter dug into the soil or applied annually as topdressing or mulch material is the best way to ensure that the soil is a healthy growing environment for plants.
  • Small grass clippings left on the lawn will break down and provide organic matter, plus they are a favourite food for earthworms.
  • There are organic lawn fertilizers available in the form of pellets for easy handling and can be applied to the lawn once a year in the early summer.

There are many good sources of information about how to compost, including how to build your own composter. Use your Green Bin for meat, fish, bones, cat litter and other items that should not go in your home composter. If you need a large quantity of compost, consider picking a load up from the City’s Trail Road facility.

Corn gluten meal (CGM) is a pre-emergent herbicide and a natural source of Nitrogen fertilizer which kills the seeds from weeds.

Ground-covering plants

Try something different! Use plants instead of grass for your lawn and garden. Consider trying something new in shady areas or in soil where grass does not do well. Check the suggestions below and ask your local nursery and garden centre for advice. Using these grass alternatives can help prevent soil erosion. However, many popular groundcovers are non-native species with invasive tendencies, which should never be planted near natural areas. Learn more about native plants.

Break up the soil with a garden fork or rototiller and dig in composted organic matter, such as material from your backyard composter, mushroom compost or well-rotted manure. Choose plants that will fit the location, the soil, sunlight and moisture conditions. Place the plants close enough together to provide proper coverage quickly; 15 - 30 cm apart (6 - 12"). Be sure to water regularly during the first year or until the plants become established. Weeding will be needed until the plants form a ground cover, mulching between plants with compost, shredded bark or other materials inhibits weeds.

Plant description Photo of plants
Ajuga or Bugleweed (Ajuga reptans)
Warning: Invasive non-native Ajuga is a fast-spreading ground cover requiring sun to light shade and moist soil. It grows 10 cm high, and develops flowers spikes, which are 20cm tall in late spring. The flowers are often deep blue though some cultivars are white or red. Shiny rosettes of leaves, either bronze-coloured or variegated grow from a horizontal stem. The cultivar ''Braunherz ajuga' is especially resistant to insect attacks. Though it is hardy to zone 4 it dies out during particularly cold winters in Ottawa.
Cotoneaster (Contoneaster dammeri) A low-growing, evergreen shrub that reaches 25 -45cm (1-1 1/2') in height and can spread more than 2m (6') because branches in contact with the soil root freely. This plant has small, glossy leaves with small white flowers that emerge in late spring, followed by red berries. Will thrive in full sun to partial shade, in well-drained soils. Ideal for slopes. CotoneasterCotoneaster
Japanese Spurge (Pachysandra terminalis) Japanese spurge forms a neat, uniform, evergreen groundcover. This plant grows best in light to full shade and moist, well-drained soils with a pH range of 5.5 to 6.5. It grows 15-20 cm (6-8") high and some cultivars have variegated leaves. Japanese SpurgeJapanese Spurge
Periwinkle (Vinca minor)
Warning: Invasive non-native Periwinkle grows in full sun to deep shade, reaching 15 cm (6") high with shiny evergreen leaves. Periwinkle blooms in spring, most have lilac-blue flowers, but there are white or violet-pink cultivars available. This plant can withstand droughts once established. Periwinkle spreads rapidly and can crowd out other plants.
Creeping Thyme (Thymus vulgaris or T. serphyllum) This is a good ground cover for full sun, loose, well-drained soil. There are many cultivars available, all with scented leaves, ranging from glossy green to variegated or woolly. In early June the 7-15 cm (3-6") tall mat is covered in tiny purple flowers. It spreads because the stems root in the soil they come in contact with. It dies out during winters with little snow cover. It is used as a ground cover, rock garden plant or between stepping-stones in a walk. Thymus serphyllumThymus serphyllum
Creeping Juniper (Juniperus horizontalis) This juniper grows slowly, but is excellent for covering rocky slopes. It requires full sun, well-drained soil and good air circulation. In fact it is tolerant of heavy alkaline soils also. 'Blue Acres', 'Blue Chip' and 'Wiltonii' have bluish foliage and very low growing. 'Green Acres' is a green cultivar. 'Plumosa' and 'Plumosa Compacta' are very popular junipers, commonly referred to as Andorra or dwarf Andorra, they turn a purplish colour after the first frost. Juniperus horizontalis cultivarJuniperus horizontalis cultivar
Bigfoot Geranium (Geranium macrorrhizum) The plant has deeply lobed leaves forming a mounding plant 20-30 cm (8-12") tall with flower stalks in early summer bearing white, pink or magenta flowers (cultivar dependant). Due to the intense heat in summer in Ottawa, it should be grown in partial shade. Plant in moist organic/humus rich well drained soil. They tolerate alkaline soils. Geranium macrorrhizumGeranium macrorrhizum
Bloodred Geranium (Geranium sanguineum) The pubescent lobed leaves are less than 5 cm (2") across and turn maroon after the first frost. Flower stalks rise out of the mounding plant, which is 30 cm (12") tall by 60 cm (24") wide, bearing magenta, rose or white flowers depending on the cultivar. It tolerates hot sunny spots in Ottawa. Plant it in rich, well-drained, moist soil. Note: There are many more species and cultivars of Geraniums that make superb ground covers. Geranium sanguineumGeranium sanguineun

Additional Ground Covers

Plant description Photo of plants
Clover (Trifolium repens) White Dutch clover is an early summer blooming, low broadleaf plant 7-8 cm (3") that is used in lawns. Until the 1980's it was included in grass seed mixes. Clover fixes nitrogen, enhancing grass growth. It needs no mowing, though tolerates it, and withstands traffic. Clover has deep roots so it is drought tolerant. Clover leaves die with frost leaving the soil exposed in the early spring and fall (coincidentally when grass grows vigorously), for this reason clover cannot be grown alone for erosion control. Clover spreads easily. CloverClover
Crown Vetch (Coronilla varia) This ground cover is ideal for large sunny banks that are too dry for grass. It forms an intertwined mass up to 30 cm thick. Like clover it is deciduous so does not cover the soil from late fall to early spring. Crown VetchCrown Vetch
Dwarf Chinese Astilbe (Astilbe chinensis 'Pumila') Low growing dark green, fine textured leaves grow from a stoloniferous root system. In mid summer it has 35cm (14") mauve-pink fluffy blooms. It spreads quickly if grown in partial shade and moist well-drained soil.  
Goutweed or Bishop's weed (Ægopodium podagraria)
Warning: Invasive non-native Goutweed grows in sun or shade and spreads extremely rapidly (invasively) the rhizomatic root system thrives in any soil type. It has green or variegated cream and green leaves and grows 25 cm (10") high. Use as a ground cover where it is restricted by buildings and concrete walkways.
Lily-of-the-Valley (Convallaria majalis)
Warning: Invasive non-native Grows about 15-30 cm (6-12") high with vertical pointed green leaves about 2.5-8 cm (1-3") wide, It has fragrant white flowers in May. Lily-of-the-valley grows in partial shade to deep shade. This plant is a vigorous spreader and if left unchecked may suppress other plants. Control its spread by digging out plants. It disintegrates in the heat of Ottawa summers if it is growing in dry soil. The bright red berries produced in summer are poisonous.
Convallaria majalisConvallaria majalis

Additional Low Growing Perennials

Plant description Photo of plants
Bishop's Cap or Barrenwort (Epimidium ssp.) Crimson, pink, yellow, or white flowers rise over a 30 cm (12") mounding plant in mid spring. Plant in moist, ordinary soil, 30 cm (12") apart as they increase slowly. They are excellent for the deep shade under trees where few other plants thrive. The foliage is semi evergreen and emerge from the winter red tinged.  
Creeping Jenny or Moneywort (Lysimachia nummularia)
Warning: Invasive non-native This ground hugging plant blooms yellow flowers profusely in late spring. It thrives in sun or shade so long as the soil is moist. It is invasive making it ideal for slopes.
European Wild Ginger (Asarum europaeum) This plant spreads to about 25cm (10") and has glossy kidney shaped leaves on 12cm (5") stems. They are ideally suited for acidic soil with a pH range of 5.5 to 6.5 growing in humus rich moist soil in shady spots.  
Spotted Deadnettle or Lamium (Lamium maculatum)
Warning: Invasive non-native Some common cultivars of Lamium include 'White Nancy' and 'Beacon Silver'. It has variegated leaves and is best in partial to full shade, and ordinary garden soil. Flower colours are white, pink and mauve-pink. It grows to approximately 20-30 cm (8-12") tall and spreads easily.
Lamium maculatumLamium maculatum
Moss phlox (Phlox subulata) Forms a moss-like mat 15 cm (6") deep; with white, blue, pale pink or dark pink flowers in spring. It needs full sun; and well-drained soil, even tolerating alkaline soils. After it blooms cut the stems back half way to promote new growth in the center and reblooming.  
Daylilies (Hemerocallis spp.)
Warning: Invasive non-native Daylilies are hardy, grass-like plants that are available as dwarfs 30 cm (12") to tall cultivars 1.3 m (4') and in many colours. They grow well in well-drained, ordinary garden soil. Yellow and orange cultivars flower best in full sun, whereas pastel coloured plants should be placed in partial shade otherwise the blooms fade.
False Rock Cress (Aubretia deltoidea) This is a greyish green, spreading plant. Thrives in full sun in well-drained ordinary garden soils. In early spring rock cress is covered in 15cm high rose-lilac to purple blossoms that fade to pink/purple. After it blooms trim back the stems to maintain it as a dense 25cm (12") wide mat.  
Foamflower (Tiarella cordifolia) This native ground cover grows 15-30 cm (6-12") tall in medium to heavy shade and rich moist soil. It produces white flower spikes in the spring.  
Hostas (Hosta spp.) Thrives in rich, moist soil in the partial to full shade, in cool yards the green and variegated cultivars grow well in full sun if the soil is moist or mulched. The leaves range in shape from narrow to broad, and come in many shades and patterns from deep blue-green to gold, plain or variegated. Hosta cultivars bloom from summer to fall having white or lilac fine lily-like flowers on spikes. Hosta CultivarsHosta Cultivars
Moss Moss lawns are becoming popular. They stand up to some traffic and certainly need no mowing. Moss grows in shady soil, that is acidic, poorly drained and has low fertility. Grass likes well-drained, fertile soil with a pH of 6.5 (near neutral). Choose which you would like, then adjust the soil pH accordingly. To get rid of moss, increase the light, dig in lime, and seed, or plant with another ground cover.  
Rock Cress or Arabis (Arabis caucasica) This is a greyish green, spreading plant. Thrives in full sun to partial shade in well-drained soils. In early spring rock cress is covered in 15cm high white blossoms that fade to pink/purple. After it blooms trim back the stems to maintain it as a dense 25cm (12") wide mat.  
Snow-in-Summer (Cerastium tomentosa) White flowers cover the grey leafed mat in late spring. The plant grows to 15 cm (6") tall by 1m (3'). It thrives in well-drained soil with low fertility in full sun. Cut back the foliage after it blooms to promote a dense compact plant.  
Stonecrop (Sedum spp.) Stonecrop can thrive in poor to rich soils and tolerates both sun and shade conditions. Yellow or red star-shaped flowers appear in the summer. Sedum acre is a low-growing, light-green succulent plant that spreads quickly. Should the plant become a nuisance, it is easy to weed. Sedum stonecropSedum stonecrop
Sweet Woodruff (Galium odoratum) This 15 cm (6") tall ground cover is best in moist shady spots where grass won't grow. It has whorled green foliage and tiny white flowers in late spring. The leaves and stems have a pleasant scent when cut or crushed.  

Lawn care tips

The Soil

Soil is the most important element for healthy grass. The roots of grass plants obtain needed moisture and nutrients from the soil and in order for roots to function they need plenty of oxygen in the soil.

All soils benefit from adding organic matter (like compost or manure) which contains nutrients and improves the soil:

  • increases moisture retention in sandy soil
  • breaks up clay soil to allow spaces for air, and water movement in the soil
  • is rich in micro-organisms that decompose clippings and slow down grubs


Keep the lawnmower blades sharp; torn grass is more susceptible to disease.

Cut about 1/3 of the grass blade. Your grass needs full leaves to create food by photosynthesis. Short lawns cannot produce enough food to be healthy.

Weed seeds need light to germinate; keeping the grass 7cm in height reduces weeds.

Digging weeds

Hand digging weeds is an effective way to remove weeds. Pick or dig up weeds and try to remove their roots.
Hand digging weeds is an effective way to remove weeds. Pick or dig up weeds and try to remove their roots.

Some weeds are acceptable, like clover. Clover grows vigorously in the hot dry weather of mid summer shading the soil, and fixes atmospheric Nitrogen, which the grass can use.

For the weeds you cannot tolerate, use a 'dandelion tool'. Remember to remove the whole root system because perennial weeds will grow again if part of the root remains.


Aerating fixes compacted soil that no longer has enough pore spaces for air and movement of water. This can be done with a machine that removes plugs of soil.

The grass must be top dressed after aeration to fill the holes in the soil with organic matter (or screened top dressing soil).

Otherwise the existing compacted soil gradually fills in the holes left by the machine, leaving the lawn uneven and the walls of the cores susceptible to drying out, damaging the roots near the core holes.

Fall is the best time to aerate and top dress compacted soil because the soil is drained, warm and the temperatures are pleasant during the day and cool at night.

 spreading compost with the back of a garden rake.
Topdressing: spreading compost with the back of a garden rake.

Almost finished topdressing.

Almost finished topdressing.

The job is complete, the grass is standing up again.

The job is complete; the grass is standing up again.


A thatch layer that exceeds 0.5 cm (¼ ", pencil thickness) can reduce the water entering the soil. Thatch results from cutting long portions of the grass repeatedly over the growing season. Earthworms love to eat short grass clippings, but long ones dry out and do not decompose easily. Homeowners should mow once a week so the clippings are short and attract the worms.

A gentle raking in the spring to remove debris is all the lawn needs.

Topdressing is the most effective way to manage thatch problems.

Reseed bare patches

Weed seeds grow well in bare spots on the lawn, so repair them as soon as possible. If the soil is compacted, loosen it, add organic matter and dig it in.

Sprinkle the seed on the soil surface, press it down, but do not bury it and keep it moist until germination occurs. Try adding some Dutch White Clover to your lawn seed mixture, which is hardy and low maintenance.

Lawn care: monthly upkeep

March (snowmelt)

  • Don't walk on soggy cold lawns
  • Remove debris from lawn
  • Look for dead patches and determine the cause (insect, disease or salt)
  • Look for bare and thin areas


  • Lightly rake to break up snow mould and to remove loose thatch
  • Apply gypsum to yards in areas where pets have damaged the lawn
  • In salt-damaged areas, aerate, apply gypsum or lime and water deeply in the early morning to flush away the salt
  • Reseed dead patches and over-seed poor areas with a grass seed mix that is suited to the sunlight conditions for each area
  • Perennial rye and fescue grasses are more tolerant of salt than Kentucky bluegrass
  • Consider alternative ground covers and/or different landscaping to prevent future problems
  • Apply corn gluten meal, a natural pre-emergent herbicide if you haven't over seeded.
  • Sharpen mower blades

Porous, black soaker hoses that leak water out through the material are a good method of applying water to the soil without excess evaporation or loss to wind. They are preferable to sprinklers where the water shoots up into the air before falling to the ground.


  • Aerate compacted areas of the lawn
  • Remove thatch if it is ½ cm, (¼" or pencil width) in depth
  • Topdress the lawn with organic material, such as compost, or with screened topdressing soil mix.
  • Spot seed and over-seed if you haven't already done so
  • Maintain the lawn at a mowing height of 7-8 cm (3"), leave clippings on the lawn, cut less than 1/3 of blade height each time.
  • Mow when grass is dry
  • Water deeply 2.5 cm (1") every 7-10 days if necessary, in the early morning
  • Fertilizers are not necessary especially if the lawn is treated with corn gluten meal, topdressed, or the clippings are left on the lawn after mowing. If fertilizing, use a balanced fertilizer
  • Hand pull weeds
  • Corn gluten meal reduces weeds and can be applied until the end of May. Itis also a source of Nitrogen fertilizer. Do not use on areas seeded with grass seed
  • As grass growth slows, reduce mowing frequency
  • Monitor and treat for: heat stress, insects and diseases
  • Hand pull weeds
  • Apply the summer treatment of corn gluten meal if needed


  • Maintain the lawn at a mowing height of 7-8 cm (3 inches)
  • Monitor and treat for: heat stress, insects and diseases
  • Fertilize with a balanced slow release or organic fertilizer (optional)
  • Water 0.5cm (¼"-1/8") every few days or let the lawn go dormant (turn brown), don't cut until it recovers after a rain
  • Cut only when necessary
  • Hand pull weeds
  • Sharpen mower blades


  • As in July, allow grass to go dormant
  • Water deeply in the early morning, 2.5 cm (1 inch) every 7-10 days if a dormant lawn is not acceptable
  • Hand pull weeds
  • Monitor and treat for insects and diseases
  • Maintain mowing height at 7-8 cm


  • The fall is the best time to dethatch, aerate and topdress the lawn
  • Over-seed and re-seed weak patches
  • Water deeply in the early morning, 2.5cm (1 inch) every 7-10 days if there is no rain
  • Monitor and treat for insects and diseases
  • Apply a fertilizer low in Nitrogen and higher in Phosphate and Potassium to increase winter hardiness (optional)
  • Hand pull weeds
  • Apply corn gluten meal if not putting down grass seed
  • Rake up leaves or chop them up with the lawn mower. Many leaves such as maple will damage the lawn if they remain on plants over winter.


  • Monitor and treat for insects and diseases
  • Chop fallen leaves with mower and leave up to 0.5cm mulch, compost the remainder if insect and disease free
  • Service lawnmower and sharpen blades
  • Plan to minimize salt damage this winter by applying gypsum to the areas of the lawn normally affected
  • Hand pull weeds
  • Apply corn gluten meal in late October if grass seed was used in September
  • Rake up leaves.

Use corn gluten meal to get rid of weeds

Corn gluten meal (CGM) is a non-toxic herbicide that prevents plants from rooting when they are germinating. For this reason, CGM needs to be applied at the right time. It is also a good natural source of Nitrogen.

CGM can be a fine yellow powder or gold pellets that smell like cereal. The pellets are easier to use on your lawn and are effective for up to six weeks.  Unlike the powdered product, the pellets will not blow away upon application or cake when watered.

Types of weeds affected

  • crabgrass (Digitaria ischaemum)
  • dandelions (Taraxacum officinale)
  • reduces the germination rate for curly dock, knotweed, lambs quarters, pigweed, and plantain.

Use corn gluten meal for:

  • lawns
  • flowerbeds
  • bulb beds
  • vegetable gardens

When to use

Three times a year is best. The first application can be done in early spring after the snow has melted -- mid-April (for crabgrass control) to mid-May (for dandelion control). The summer application should be done mid- to end of June. During July to mid-August, the lawn will be dormant or semi dormant depending on the temperature and rainfall. Avoid watering at this time to help reduce the survival of recently germinated weed seeds and the eggs of lawn insects such as the European Chafer Beetle, Japanese Beetle and June Beetles (lawn grubs).

Overseed from mid-August to mid-September if the lawn is not robust. Grass seed needs at least 6 weeks to establish before winter arrives. Do not apply CGM until the grass seed is established as it will prevent germination of these seeds as well.

If no grass seed has been put down, the third CGM application can be done in late August, to stop the weed seeds that have blown in during the late summer. Otherwise the third application is done in mid-September to late October, after the grass seed is established, and late enough to be active in the very early spring. This is known as dormant fertilization.

How to use

Use the corn gluten meal with a fertilizer spreader and then water the lawn and let it dry out. A ratio of about 10 kg CGM to 100 sq m is recommended for weed control.

The CGM will still be effective if you do not have a chance to water your lawn immediately after applying it, because the proteins are released every time it rains or the lawn is watered, until the pellets decompose.

Mix the CGM into the top 1/4" of soil before transplanting flats or container grown annuals, perennials or vegetables. These plants will not be harmed because they have a large strong root system.