Lawn Maintenance

Agdex#:	273
Publication Date:	April 2008
Order#:	08-017
Last Reviewed:	April 2008
History:	This factsheet replaces OMAFRA Factsheet, Lawn Maintenace 03-059
Written by:	P. Charbonneau - Turfgrass Specialist/OMAFRA

Introduction
Maintaining a healthy lawn involves using good maintenance practices throughout the growing season. These include proper mowing, fertility, irrigation and thatch control. These techniques provide a dense, healthy, high quality lawn.

Mowing
The importance of good mowing practices is often overlooked but has a major influence on turf density, uniformity and aesthetic quality of a home lawn. It is the most repetitious and time-consuming maintenance practice and it is often done incorrectly.

Frequency and Height
Turf can be mowed frequently, provided no more than one-third of the grass blade is removed in a single mowing. Mow as high as possible. Lower mowing produces a shallow root system. Shallow grass roots cannot take up water and nutrients and make the lawn susceptible to drought stress. Low mowing encourages broadleaf weed invasion and invasion from grassy weeds such as creeping bentgrass and annual bluegrass. It is best to mow a lawn when the leaves are dry. Dry grass cuts cleanly and clippings distribute more evenly.

Clippings
Leave clippings on. If they are excessively heavy, rake them up and remove them. Clippings contain nutrients and water, breakdown rapidly and do not contribute significantly to thatch. You can cut down your fertilizer (especially nitrogen) by 20%-35% by leaving the clippings on. Mowers

Mowers
Mowers need the capacity and power to handle the area being mowed. Consider weight, manoeuverability, ease in starting, ease of adjustment of height of cut and safety features. Keep mower blades sharp for a good quality cut. Select mulching type mowers that recycle grass clippings.

Fertility
Understanding and implementing a well-balanced fertilizer program is one of the most important factors in maintaining an attractive healthy lawn. The three main nutrients required by lawns are:

• Nitrogen (N)
• Phosphorus (P)
• Potassium (K)

Nitrogen promotes dark green colour, leaf and blade development, and density of the turf. Phosphorus is important for good root and rhizome development and promoting plant maturity. Potassium contributes to the general vigour of the plant, promotes wear and drought tolerance and hardiness against winter injury.

Amount of Nutrients
The amount of nutrients required by a home lawn is best determined by soil testing. A soil test will provide levels of phosphorus, potassium, pH and lime requirements. There is no soil test for nitrogen. Generally, 1.5-2 kg/100 m2 of actual nitrogen can be applied throughout the season, split into 2-4 applications. In the absence of a soil test, a 4-1-2 ratio (N-P-K) such as 20-5-10 is recommended. The three numbers on the fertilizer bag represent the amount of N, P and K in that order. For example the 20-5-10 fertilizer ratio listed above contains 20% N, 5% P and 10% K. Nitrogen has to be applied every year, while phosphorus and potassium are relatively stable in the soil. If the lawn is on sandy soil, higher potash or more frequent applications may be required because it may leach. On newly established lawns, higher levels of phosphorus and potash may be required. Fertilizers

Common turf nitrogen fertilizers and their properties are listed below in Table 1.

Type	Examples	Response	Problems	Water Solubility	Potential for burn
Inorganic	ammonium nitrate ammonium sulfate	immediately available quick green up	readily leaches causes lush growth	High	High to very high
Organic	activated sewage sludge   animal by-products plant by-products	slow release low leaching	more expensive than inorganic forms	Low	Low
Synthetic	IBDU urea formeldehyde sulfur coated urea polymer coated urea	slow release low leaching	release rate is dependent on temperature or moisture levels depending on the source	Very low	Low to very low

 

Timing
The timing of fertilizer application is determined by the total amount of fertilizer you wish to apply to your lawn. Table 2 below has some suggested timing of fertilizer applications based on the number of yearly applications.

Number of yearly applications*	EarlySpring	LateSpring	EarlySummer	Late Summer/Early Fall	Late Fall
1	—	—	—	1st application	—
2	—	2nd application	—	1st application	—
3	—	3rd application	—	1st application	2nd application
4	—	3rd application	4th application	1st application	2nd application

* each application consists of 0.5 kg of nitrogen per 100m²

Late fall fertilization with a quick release nitrogen fertilizer is beneficial for home lawns. Apply when the lawn has stopped growing but is still green. It:

• increases fall and spring root growth
• promotes a thicker lawn
• results in an early spring green up.

The lawn will green up earlier in the spring and will not give the rapid flush of shoot growth that occurs with spring-applied nitrogen.

Application
An even application of lawn fertilizers is very important in achieving a uniform green lawn. If using a drop type spreader, operate it the long way of the lawn. First apply header strips at each end of the lawn to provide room for turning. Overlap one wheel's width when spreading the fertilizer and shut off the spreader when reaching the header strips. With a centrifugal type spreader, make two split (half rate each) applications at right angle to each other. Always make sure the spreader is properly adjusted, otherwise you could end up with striping or uneven colour.

Irrigation
When normal rainfall does not provide enough moisture during the growing season grass goes dormant and turns brown. To ensure a high quality lawn the lawn must be watered. Signs that a lawn needs water include:

• footprints remain while walking across the lawn
• a slight change in colour to dark blue-green and grass blades folding inwards.

Frequency and Timing
Water in the early morning when there is little or no wind. This allows more even water distribution. Water before mid-day when the evaporation rate is the highest. Watering can be done in the evening, but this may encourage disease developing. Most disease-causing fungi require several hours of leaf wetness for infections and disease to occur.

Amount of Water
Too much water can cause thatch, fertilizer leaching, increased disease or grass weed problems such as creeping bentgrass, annual bluegrass or rough bluegrass. Too little water can cause shallow rooting of the turf, which makes the lawn susceptible to disease, drought stress or winter injury. Infrequent, thorough watering is best. When the lawn wilts, wet the entire area to a depth of 10-20 cm. The amount of water required to achieve this depends on soil characteristics. To measure how much water has been applied, place a straight-sided can or jar in the area being watered, and then check the water level in the can or jar. Approximately 2.5-4 cm of water in the can corresponds to an adequate irrigation of the lawn. Areas of the lawn needing more water include slopes, areas near buildings, curbs, sidewalks and light soils. Low lying areas, shaded areas and heavy soils may not need as frequent irrigation.

Dormant Lawns
During extended dry periods, a lawn may turn brown and go dormant. A lawn can survive from 4-6 weeks in a dormant state during summer dry periods. Once the rains return the lawn will green up in 7-10 days. If the lawn is dormant:

• Keep traffic off
• Stop mowing
• Do not fertilize

Irrigation Equipment
Hose watering is suitable for small areas only. A sprinkler attachment provides adequate coverage for an average size lawn despite the inconvenience in moving the sprinkler and a lot of water can be wasted. An underground irrigation system is the most expensive, but also the most efficient method, and may be considered for very large lawns or industrial properties.

Thatch
Thatch is a layer of organic matter made up of decaying grass leaves, stems and roots that build up in between the lawn and soil surface. It is a common problem on home lawns, particularly for lawns established for several years.

Identification
A thatchy lawn feels very spongy when walked on. Cut a triangular patch of lawn with a sharp knife and lift it back to measure the thickness of the thatch layer. More than 2.5 cm of thatch is too much.

Why is Thatch a Problem?
Thatch harbours insects and diseases. Thatch can restrict grass roots from growing into the soil root zone, resulting in a shallow rooted lawn. Thatch interferes with water infiltration.

Minimizing Thatch
Cultural practices that minimize thatch development are:

• frequent mowing
• proper watering
• proper fertilization

Excess thatch can be removed by vertical mowing or core aerating. Core aerate using a hollow steel tine core aerator which removes cores of soil. This physically breaks up the thatch, brings up beneficial soil micro-organisms that help break down the thatch and alleviates compaction.

Timing
Dethatch or aerate in spring and fall during periods of good growth, allowing for quick lawn recovery.

Overseeding and sodding
Overseeding is a method of thickening up a lawn that has become thin or damaged by insects, diseases , weeds, drought, excessive traffic or other types of damage. To insure success, add compost, peat or topsoil before overseeding. Overseed at double the seeding rate for establishing a new lawn. The best time to overseed a lawn is in the fall (mid-August to mid-September). Keep the overseeded area moist by watering several times a day. One week after seeding, reduce watering to twice a day until seedlings are established.

Sodding is another method of repairing damaged lawns. Cut out dead or damaged areas to a depth of roughly 4 cm. Rake the soil, add fertilizer and place the sod on top of the soil. Insure good sod/soil contact by stepping on the sod or rolling it. For the best results, sod should be watered within an hour of being laid. Water sod frequently and make sure it does not dry out until it is fully rooted. Newly sodded areas will be rooted in 10 days to two weeks. Refer to OMAFRA Factsheet, Lawn Establishment, Order no. 08-025W and Lawn Renovation, Order no 08-021W for more information on overseeding and sodding.

A summary of the timing for fertilization, mowing, irrigation, over seeding and aeration can be found in Table 3.

	Early Spring (May)	Late Spring (June)	Summer (July)	Late Summer (August)	Fall (September)	Late Fall (October)
European Chafer and Japanese Beetle	check for grub damage	Overseed or sod damaged areas				check for grub damage
Hairy Chinch Bug			Check for chinch bugs	Overseed or sod damaged areas
Sod Webworm					Check for sod webworm Overseed or sod�damaged areas
European Crane Fly	Check for eatherjackets	Overseed or sod damaged areas
Diseases (turf diseases are treated with cultural practices	Assess snow mould damage, rake to encourage the turf to dry up and fertilize lightly to encourage recovery.	Monitor for leaf spot, especially in excessively wet springs followed by hot, humid conditions. Raise mowing height and fertilize lightly to encourage recovery. Avoid heavy applications of nitrogen in early spring to minimize leaf spot and melting out.	Monitor for necrotic ring spot. If it is a problem, aerate and overseed with perennial ryegrass in the late summer/ early fall.	Continue monitoring for necrotic ring spot. Follow cultural practices in previous column. Monitor for dollar spot. Fertilize if dollar spot becomes a problem.	Monitor for rust. If rust is a problem fertilize turf. Avoid fertilizing from mid-Sept. to mid-Oct.
Fertilization (N-P-K) P and K to be established by soil tests		**	** only if lawn irrigated regularly or a wet season	**		** (late October)
Mowing	Mow as high as possible. Do not remove more than 1/3rd of the leaf blade with each mowing.	Mow as high as possible. Do not remove more than 1/3rd of the leaf blade with each mowing.	Mow as high as possible. Do not remove more than 1/3rd of the leaf blade with each mowing.	Mow as high as possible. Do not remove more than 1/3rd of the leaf blade with each mowing.	Mow as high as possible. Do not remove more than 1/3rd of the leaf blade with each mowing.	Mow as high as possible. Do not remove more than 1/3rd of the leaf blade with each mowing.
Irrigation	Irrigate turf at least once a week with 2.5 cm of water if there is insufficient rainfall to keep turf from going dormant. Irrigation will help turf withstand grub feeding.	Irrigate turf at least once a week with 2.5 cm of water if there is insufficient rainfall to keep turf from going dormant. Irrigation will help turf withstand grub feeding.	Irrigate turf at least once a week with 2.5 cm of water if there is insufficient rainfall to keep turf from going dormant. Irrigation will help turf withstand grub feeding.	Irrigate turf at least once a week with 2.5 cm of water if there is insufficient rainfall to keep turf from going dormant. Irrigation will help turf withstand grub feeding.	Irrigate turf at least once a week with 2.5 cm of water if there is insufficient rainfall to keep turf from going dormant. Irrigation will help turf withstand grub feeding.	Irrigate turf at least once a week with 2.5 cm of water if there is insufficient rainfall to keep turf from going dormant. Irrigation will help turf withstand grub feeding.
Overseeding		**if turf has been damaged by diseases or insects		**if turf has been damaged by diseases or insects
Aeration		**		**

** application

Weed Management
A thick vigorous lawn is the best prevention against weed invasion. A dense stand of turf can compete successfully with weed seedlings for light and nutrients. Low mowing encourages broadleaf weed invasion and invasion from grassy weeds such as creeping bentgrass and annual bluegrass. Provided that a lawn is mowed in a timely fashion, at the proper mowing height, fertilized regularly and irrigated properly, weed invasion can be kept to a minimum.Problem weeds include both broad-leaved and grass weeds. They may occur when there are thin or damaged areas or heavily trafficked areas Control

Control problem weeds by:

• hand pulling
• hand raking
• mowing to prevent seed formation

Insect Management
A healthy, well maintained lawn is the defense against insect invasion. Insect damage is usually less severe on well watered lawns. Insects that infest home lawns are generally difficult to notice and their presence goes undetected until significant damage has been done. Insect damage can often be mistaken for drought damage. If the lawn remains brown or shows signs of thinning out despite watering, then closer examination for insects should be done. Regular inspection of the lawn including leaves, stems, roots, thatch and soil will help to determine if the problem is insect-related. The most common lawn insect pests are:

• Hairy chinch bug
• Grubs
• Sod webworms
• European crane fly
• Bluegrass billbug
• Turfgrass Scale

Hairy Chinch Bug
Hairy chinch bug damage starts to become noticeable from mid-July to mid-August. It causes damage by sucking plant juice from the grass stems with its piercing and sucking mouth parts. The first signs of damage are small fist sized sunken areas in the lawn. As the insects continue to feed these areas can grow very rapidly into large dead areas. Damaged areas are often taken over by weeds. Adults are very small (4 mm long) and their wings form an X on their backs. One method of detecting chinch bugs is to cut the ends of a metal can to make a cylinder and force it into the ground. Fill the cylinder with water, chinch bugs will float to the surface if they are present in the lawn. For more information consult OMAFRA Factsheet, Hairy Chinch Bugs in Lawns, Order No. 08-019. Grubs

Several species of grubs can cause damage by feeding on grass roots in home lawns. The most common grubs are:

• June beetle
• European chafer
• Japanese beetle

If animals such as skunks begin digging up the lawn or if small irregular patches of grass turn brown, it may indicate grubs present in the lawn. Check for grubs in late summer or early fall before damage is noticed. Lift a section of sod and soil with a spade, 10 cm square and look for white, C-shaped grubs in the soil. Keeping the lawn well watered helps minimize grub damage. For more information on grubs consult OMAFRA Factsheet, Grubs in Lawns, Order No. 08-023W.

Sod Webworms
Sod webworms are caterpillars that feed in the thatch on home lawns. The adults are small tan moths that fly around lawns at night. The caterpillars grow to 2 cm and are tan in colour. They have dark spots on their backs. They feed in the thatch causing damage that is similar to grub damage, where areas of turf can be lifted like a carpet. They also leave behind soft green fecal pellets in the areas they are feeding. The damage occurs in September.

Bluegrass Billbug
Bluegrass billbugs are in the weevil family. The adults are black and 5 mm long. Larvae are small white and legless with a brown head. Damage begins with small groups of plants turning yellow and dying. This occurs in mid-July to mid-August. Damage is usually spotty and rarely affects a whole lawn. Billbugs leave behind a sawdust-like excrement in areas they have been feeding. This is helpful in diagnosing the damage.

European Crane fly
The European crane fly is a relatively new pest to lawns in Ontario. The adult cranefly resembles a large mosquito. The larvae are known as leatherjackets. They are light greyish-brown with black specks. There is no visible head region. They range in size from 0.5-3.0 cm in length. Leatherjackets feed primarily on grass shoots during the evening and on grass roots during the day. Damage begins to show between early to mid-May and peaks by mid-June. Heavy infestations of leatherjackets can chew the grass down to the bare soil.

Turfgrass Scale
Turfgrass scale is a typical scale insect that resembles an egg cut in half lengthwise. It is brown with a yellow stripe in the middle. The immature stage is called a crawler and it is the size of the head of a pin. Typical damage is small patches of dead grass that do not green up in the spring. They are found mainly on sodded lawns and in general, do not cause much damage. During early July crawlers can be found on shoes when you walk through the lawn. Endophytes

One way to combat the damage caused by leaf feeding insects is to plant grasses that contain endophytes. Endophytes are fungi that grow inside the grass plant and make it taste bad. Lawn insects repelled by endophytes are hairy chinch bugs, bluegrass billbugs and sod webworms. Lawn species that may contain endophytes are perennial ryegrass, fine fescues and tall fescue. Consult your local garden centre or seed supplier about the endophytic grasses they sell. A summary of the major turf insect pests, how to identify them, the damage they can be found in Table 4.

If a lawn becomes damaged or thins as a result of insect feeding, it can be repaired by overseeding or sodding. Refer to these sections in this factsheet for more information.

Table 4. Summary of Lawn Damaging Insects

Insect	Description	Damage	Detection
Hairy Chinch Bug	start as brick red nymphs in June as they mature they turn grey adults are 4mm long and have an X on their backs	turf appears sunken damage is caused by sucking plant juices from the grass leaves and stems with heavy infestation large areas of turf may die dead turf does not pull out easily (still well rooted) can destroy an entire lawn in a season	cut the ends off of a metal can to make a cylinder and force it into the lawn fill can with water and chinch bugs will float turf species containing endophytic fungi show resistance to chinch bug feeding
Grubs	c-shaped white larvae with brown heads range in size from 1-3 cm depending on the species	feed on turfgrass roots lawn lifts up like a carpet animals (skunks, raccoons and starlings) dig up grubs	cut 3 sides of a square and lift to uncover grubs
BluegrassBillbug	adults are weevils about 5 mm long larvae are small white and legless with brown heads and are 5 mm long	amage starts as small areas of yellow grass that pull away above the thatch usually do not destroy entire lawns	sawdust excrement is found in the areas where the billbugs are feeding turf species containing endophytic fungi show resistance to chinch bug feeding
Sod Webworm	adult is a fawn coloured moth caterpillar is tan in colour	feed in September in thatch turf pulls away like a carpet	soft green pellets found in the dead grass area where the grass can be easily pulled away  turf species containing endophytic fungi show resistance to chinch bug feeding
European Crane Fly (leatherjackets)	adult resembles a large mosquito larvae are called leatherjackets greenish grey with no distinguishing features	leatherjackets feed in May and early June chew grass blades back to the ground level	�         examine the top of the thatch in thinned areas and leatherjackets will be visible
Turfgrass Scale	typical scale insect resemble an egg cut in half lengthwise brown with yellow stripe in the middle immature stage called crawlers and are the size of the head of a pin	small patches of dead grass that do not green up in the spring mainly on sodded lawns	during early July crawlers can be found on shoes when you walk through the lawn do not cause much damage

 

Figure 1. Hairy Chinch Bug

Figure 2. Grubs

Figure 3. Bluegrass Billbug

Figure 4. Sod Webworm

Figure 5. European Crane Fly (leatherjackets)

Figure 6. Turfgrass Scale

Other Pests

Moss

Mosses are primitive forms of green plants that form tangled clumps that grow in amongst a lawn. Moss plants have a tremendous capacity to spread. They produce large numbers of spores, each of which can give rise to a new moss plant. Mosses are poor competitors with a healthy lawn and are only a problem when the lawn is weakened by poor growing conditions. The following conditions weaken a lawn and promote moss invasion:

• poor aeration
• poor drainage
• low fertility
• high acidity
• heavy shade

Cultural methods can be effective in controlling moss. They are:

• Adequate fertility, especially nitrogen (2.0 kg per 100 m² of actual N).
• Control thatch by vigorous raking, aeration or vertical mowing.
• Reduce shade by pruning trees.
• Maintain a soil pH of between 6 to 7 - apply lime if soil is acidic.
• Improve surface drainage.
• Reduce compaction and increase aeration by spiking slicing or aerifying with a mechanical aeifier.
• Do not overwater.
• Do not remove more that 1/3 of the top growth at one time when mowing and mow at a height appropriate for the grass species.

Disease Management
Disease problems in home lawns are minimal. Excessive fertility can cause succulent growth that is more susceptible to diseases. When establishing or renovating a lawn area, select varieties that are resistant to various diseases. Improper irrigation also contributes to lawn diseases. Make sure to water in the early morning to minimize the length of time that the lawn stays wet. A summary of common turfgrass diseases on home lawns is shown in Table 5.

If a lawn becomes damaged or thins as a result of lawn diseases, it can be repaired by overseeding or sodding. Refer to these sections in this factsheet for more information on overseeding and sodding.

Table 5. Summary of Common Lawn Diseases

Name	Description	Conditions favouring disease	Damage and Control
Fairy Ring	circles or arcs of dark green grass or dead grass may be mushrooms growing in the ring	decaying organic matter in soil	repeated deep cultivation and drenching with water
Leaf Spot	begins as small oval reddish-brown spots on leaves in early spring under hot, humid conditions spots can spread to kill stems and crowns to cause lawn to thin or die out (melting out)	hot, humid conditions lawns that have been fertilized recently Kentucky bluegrass is most susceptible	raise mowing height lightly fertilize to encourage recovery Irrigate in the morning only
Mushrooms	grow after a rain		mowing will keep them under check
Necrotic Ring Spot	appears as roughly circular patches often with green tufts of grass inside resembling a donut	wet, cool conditions in spring promotes disease symptoms appear during a drought often a problem of sodded lawns	encourage deep rooting water lightly and frequently during dry periods overseed with "turf-type" perennial ryegrass
Powdery Mildew	greyish-white powder on leaves and stems	haded areas that are kept moist and have poor air circulation	decrease shade and improve air circulation usually thins turf but does not completely kill it
Rust	yellow flecks on leaves reddish-brown pustules form which produce reddish yellow spores   rust spores can be rubbed off easily during a heavy infection found on shoes and mower blades	stress caused by low nitrogen and drought perennial ryegrass is the most susceptible	fertilize and water infrequently mow high and frequently
Snow Moulds	circular or irregular straw-coloured patches on lawn after snow melts	long periods of snow cover, lush grass growth and long matted grass going into the winter more prevalent in areas where snow has drifted or where snow is piled up during winter	do not apply nitrogen during Oct. in the spring, rake matted areas to encourage drying and fertilize lightly to encourage recovery

 

Figure 7. Fairy Ring

Figure 8. Leaf Spot

Figure 9. Mushrooms

Figure 10. Necrotic Ring Spot

Figure 11. Powdery Mildew

Figure 12. Rust

Useful References

• Grubs in Lawns, Order No. 08-023W
• Hairy Chinch Bugs in Lawns, Order No. 08-019
• Lawn Establishment, Order No. 08-025W
• Lawn Renovation, Order No. 08-021W