Last Updated May 20 2014. All material copywrite protected.
A lawn is a wondrous thing. It's a little like the Marvellous Toy in the Irish Rovers Song: "It went ZIP when it moved, and POP when it stopped, and WHIRRR when it stood still; I never knew just what it was, and I guess I never will."
We would like our lawns to be deep green in colour, cool to lie on, and soft and luxurious, all with crisp clean edges and no weeds. We are frustrated because our lawns sometimes do not measure up. Then we are confused by the environmentalists and the xeriscape people who tell us that lawns are not good.
A definitive discussion of lawns would deal with irrigated and non irrigated lawns and then with "warm season" and "cool season" lawns. Because this article is aimed at the home owner in the Northern Great Plains region, I will deal only with irrigated lawns in temperate climates.
Let's take a look at these natural conditions. Does it rain for 10 minutes every morning? Does a great bird fly over 3 or 4 times a year and deposit a uniform layer of chemical fertilizer? Does another unimaginable creature lay down a noxious liquid that is toxic to everything except the special grasses? Do the deer and mountain goats come at 10:00 am every Saturday morning, clip the desirable grass to a uniform height and deposit the "clippings" in a special container for removal to another "meadow"?
Let's get real. It is possible to relocate these specially adapted species of grass to our urban yards and to nurture them there into a pure stand which is both beautiful and functional. However, it is important to understand the natural interactions that predate all the books and articles on the science and culture of turf grass.
Allow me to digress for a minute. The soil is a natural system of indomitable momentum. Even humans, the great destroyers, could not harm it significantly until they learned how to use the great might of nature against nature itself. As humans discovered the natural storehouses of energy in the form of hydrocarbons such as coal and oil and developed the internal combustion engine, they began to mine the very life from the soil. This process is continuing all around us. The evidence is to be seen everywhere in the form of wind and water erosion, drastically reduced productivity of farmland without massive chemical inputs, the continual appearance of new insect and disease problems, and the endangerment of evermore plant and animal species. Today, even the experts are hard put to find undamaged ecosystems in most areas of human occupancy. These actions are not deliberate or malicious. It is human nature to dominate and to disregard any consequences that don't inconvenience us directly or immediately.
Fortunately, the urban lawn requires very little in the way of topsoil--much less than most other landscape plants. The grasses are nature's great healers. They can establish under very poor soil conditions ranging from heavy clay to almost pure sand or gravel. Erosion by wind and water is quickly reduced to zero. Each season, the plants generate a new root system. Most of the previous year's roots decay slowly in the soil providing the organic components which are necessary for the establishment of the microorganisms which make the soil alive and productive. Light sandy and gravelly soils have increased moisture and nutrient holding capacity with each passing year. Heavy clay soils soon develop a pebbly texture which greatly enhances aeration and water infiltration.
Problems with existing lawns are seldom caused by the inadequacies of the soil, but by maintenance practices which damage the soil and prevent it from healing itself as it would naturally tend to do. Examples of such practices include overwatering, serious compaction, and the continual removal of organic matter.
The common wisdom has been to provide a new landscape with about 6 inches of good dark topsoil. Because of the cost ($12.00 to $15.00 per cubic yard) and the ethical considerations of stripping topsoil, I would suggest that 2 to 3 inches is adequate for lawn areas. In reclamation studies it has been shown that even an inch of topsoil is enough to inoculate the area with the micro organisms that give life to the soil. Areas for vegetable gardens, flower beds, and shrubbery will, however benefit significantly from a greater depth of topsoil, 8 to 12 inches is not too much. These areas should actually be excavated before the topsoil is applied.
For irrigated sites, topsoil with a sandy texture is always better than heavy, sticky topsoil. A good dark colour is a fairly reliable indicator of adequate organic content. For a small premium, some suppliers of topsoil will premix it with well rotted manure or bulk peat moss. Usually, this is an excellent value for your money but for lawn areas, at least, certainly isn't necessary. Soil with large clods of sod or chunks of clay is not a good value at any price.
To calculate the amount of topsoil you require refer to the following table:
At a depth of 3", one cubic yard of topsoil covers 162 sq.ft.
Before topsoil is applied the subsoil should be levelled carefully so that the topsoil can be reasonably uniform in depth. The surface should be scarified to a depth of at least 4 inches. This is especially important on construction sites where everything has been packed rock hard by heavy machinery and other construction activity. If this is not done, it may take years for plant roots to penetrate this layer adequately.
Unfortunately, the only machine available for this job is usually a rototiller. I have come to hate these machines because it is their nature to pulverize the soil. This is very destructive, especially with the heavier soils. A cultivator with spring shank chisels or sweeps is much better but usually hard to find. Even the teeth on a bobcat or front end loader bucket will do a reasonable job of the scarification if the subsoil is not too hard packed.
Now that the subsoil is adequately prepared, it is time to dump and level the topsoil. A good bobcat or loader operator will spread the topsoil with a minimum of compaction. Once the topsoil is spread, there should be no need for further tilling or cultivation. I will deal with seed bed and sod bed preparation towards the end of this article.
Aeration with a coring or hole punching machine should never ever be necessary unless the lawn is subject to unusually high traffic. Soccer and football fields will sometimes benefit from aeration, especially if the soil is a heavy clay type or the field is played on when it is too wet. Similarly, if a lawn has been subject to persistent vehicular traffic, aeration can speed the natural healing process. Sandy soil naturally allows air infiltration and clay soils that are not mistreated will naturally develop a pebbly texture which also allows more than adequate air infiltration. Soil which is continually water logged has little room for air in the tiny spaces between soil particles because they are already filled with water. Ideally the soil should be allowed to become quite dry between rain showers or artificial waterings. Then as the water sinks into the soil, it will actually draw the air in behind it. For more information about air/water relationships see watering.
The dried tissue of healthy plants contains 17 elements. Although these 17 elements are all absolutely essential for plant growth, we need only concern ourselves with very few of them. Hydrogen, Carbon, and Oxygen make up about 96 per cent of the dry mass. Since the plant obtains these elements from the water and air, they are never limiting in outdoor growing areas and we do not think of them as nutrients.
The remaining 4 per cent of dried plant tissue is made up almost entirely of Nitrogen, Potassium, Calcium, Magnesium, Phosphorus, and Sulphur in order of decreasing abundance. Of these, Calcium, Magnesium, and Sulphur are almost never in short supply and thus are not usually thought of as "fertilizer". This leaves the "fertilizer trio", Nitrogen, Phosphorus, and Potassium . The numbers on the fertilizer label indicate the percentage of these three elements or compounds thereof in order. Thus a 16-20-0 fertilizer would have 16 per cent Nitrogen, 20 per cent Phosphorus, and 0 per cent Potassium.
The remaining 8 elements are Chlorine, Iron, Boron, Manganese, Zinc, Copper, Nickel, and Molybdenum the respective concentrations of which are one hundredth of one per cent for Chlorine and one hundred thousandth of one per cent for Molybdenum. These are sometimes referred to as the micronutrients. Under normal growing conditions these are almost never limiting.
So what does all of this have to do with growing a great lawn? I included this level of detail to make the point that there is no such thing as a special or magic fertilizer. Besides air and water, it is well known and documented that any plant requires only 14 elements and many in such minute quantities that it is difficult to sufficiently eliminate them as impurities from laboratory reagents to even demonstrate that a plant grown without soil is harmed by their absence. If these elements are not in short supply, the plant will not benefit from the addition of more--it may indeed be harmed. For example, it is well known that animals need a small amount of salt in their diets. However, it is also well known that too much salt can be harmful. Indeed, salt in excess is more toxic that many herbicides and insecticides in common use.
On the prairies, we need to concern ourselves with Nitrogen and Phosphorus and that's all. Potassium, the main ingredient in potash, is abundant in prairie soils. Nitrogen is associated with lush vegetative growth and Potassium is associated with plant maturation and the bearing of seeds or fruit. Thus lawns will benefit from the addition of Nitrogen and gardens and shrub beds will benefit from the addition of Phosphorus. Too much Nitrogen on the vegetable garden will result in large, lush, and bushy plants with little fruit. Similarly too much Nitrogen on a lawn will result in a turf that is too soft and lush to withstand normal wear and tear.
For lawns Phosphorus is seldom a limiting factor. However, since much of our commercial topsoil comes from "heavily mined" crop land there may be a Phosphorus deficiency before you even start. For this reason, when new lawns are being established, it is a good idea to spread 16- 20-0 fertilizer at a rate of about 10 pounds per 1000 square feet. This fertilizer should be mixed into the top 4 inches of soil because the Phosphorus is not readily soluble and would thus take years to move into the root zone.
Nitrogen is a different story. An actively growing irrigated lawn requires about 3 pounds of actual Nitrogen per 1000 square feet per year. Since Nitrogen is very soluble in water it is easily leached out of the root zone and needs to be replenished on a regular basis. If none of the clippings are removed and they are short enough to settle deep into the lawn where they will decompose, only a small amount of nitrogen will need to be added. As a general rule of thumb, apply 34-0-0 fertilizer two or three times in spring and early summer at a rate of 3 to 5 pounds per 1000 square feet. For most city yards, a 50 pound bag of 34-0-0 is more that enough for a whole season.
A shortage of Nitrogen is easy to judge. Go across the street and compare your lawn with the neighbours' both ways up the block. If yours is one of the greener ones, you probably do not need to fertilize. If it is a lighter green than many of the other lawns, then an application of Nitrogen is probably in order.
The best way to apply granular fertilizer is with a hand held or shoulder bag type of "whirly- bird" broadcaster--the one with the crank on the side. I like the hand held version. It only holds about 5 pounds of fertilizer and thus reduces the temptation to over fertilize.
Avoid heavier applications. They only result in a lawn that is too lush and one that requires mowing every third or fourth day. The excess will certainly find its way to our watercourses where it is nothing short of toxic.
Avoid applications before the end of May. The levels of Nitrogen in the soil are naturally somewhat elevated in the spring because of decomposition during the fall and early spring when the plants are not utilizing it because the soil temperatures are sub-optimal. Before the end of May the factors limiting growth are much more likely to be soil poor soil aeration because of water logging and, as already mentioned, low soil temperatures.
Avoid applications after the beginning of September. It is not good to encourage lush growth in the fall.
Generally, slow release and organic fertilizers are a waste of money. The concentration of actual nutrients is often less that a quarter of what is contained in the chemical fertilizers while the price per pound is usually more than four times as high. The nice picture on the bag and the advertising hype will not help your lawn that much!
Slow release fertilizers and fertilizers with very low concentrations of actual nutrients are good for people who can't resist giving the "triple dose". Otherwise they are of little benefit because the soil has a remarkable ability to absorb and hold nutrients until they are needed. The "one application is good for all year" fertilizers are mostly chemical fertilizers with have been encapsulated in plastic or other very low solubility resins which delay their release. They were originally designed for very specific situations where overwatering could not be avoided. It was the marketing people that brought them into the lawn care realm, not the horticulturists.
The organic fertilizers fall into two categories. The liquid ones and some of the powders are nothing more or less than chemical nutrients derived from organic sources such as the decaying fish parts or pulverized bone. Others are made of partially composted materials and sometimes sewage sludge. These are very equivalent to the decomposing clippings at the base of your lawn. Although they appear to be environmentally friendly, one would have to question the fact that many of them have been transported hundreds and even thousands of miles from their place of origin to the Canadian prairies.
Mowers range in price from about $250 to well over $2000. Most home owners will get many years of excellent service from a bottom end chain store model. Remember, however, that you will be sharing between 15 and 40 hours of time with your mower every year. The more expensive models start more easily, run quieter, are more corrosion resistant, and are easier to push because they usually have bigger wheels and better bearings. If you have a large yard or significant slopes to contend with, consider a self propelled model. Although these models are more expensive and have more parts which will require service over time, they certainly require less effort to operate.
I love the small ground driven reel mowers. These mowers have no engines to give trouble. The only noise is a pleasant "whirring" sound. When properly tuned, they have the cutting action of a sharp scissor. Because they are almost indestructible they can often be bought at garage sales for a very low price. Although they are very environmentally friendly, they do have some disadvantages. They don't work well when the lawn is overgrown and they are normally only available in 12 or 15 inch widths.
I don't like bagging mowers of any kind. It is probably easer to mow twice as often and let the clippings fall where they may than to bag and remove the clippings. Furthermore, the practice of bagging and removing grass clippings is very damaging. The roots of grass plants are very good at finding and absorbing the nutrient compounds that exist in the soil. This mining process is very precise and efficient. The absorbed compounds become an integral part of the plant structures. When the plant structures are removed in the form of clippings or seeds, bagged, and removed, the nutrients are lost to the soil forever. The soil becomes impoverished while disposal sites and water systems are damaged by an overabundance of these "beneficial" compounds.
Mulching mowers are great in principle. Because they have no discharge chute or a discharge chute that is blocked or covered over, they are somewhat safer in that they are less likely to discharge small stones or other debris that might be in the lawn. However, they don't work well in tall grass, have a tendency to rough up the grass unnecessarily, and frequently don't lay down the "mulched" clippings very evenly. The mulching feature may be more of a selling gimmick than a real benefit.
Mowers need to be maintained. If you are not comfortable with changing the engine oil, cleaning the air filter, or sharpening the blade, take your mower to a reputable dealer annually for service and tuneup. The benefits are a mower that runs smoothly, starts when you want it to, and lasts for many years.
Mow regularly. During the prime growing time of late spring and early summer, once a week will probably not be enough. Ideally the clippings should never be more than 1/2 inch long. Short clippings will settle deeply into the lawn where they will decompose over time, freeing the nutrients to be reused. These decomposing clippings form a cushion which makes the lawn soft and resilient to play on and at the same time protects the grass shoots from the wear and tear of severe traffic. Imagine a blade of grass on the sidewalk. It will suffer serious harm if you step on it. Now imagine a thin layer of clippings between the blade of grass and the sidewalk. With this cushion, it can easily endure your foot print without suffering significant harm. Longer clippings will remain suspended above the soil and eventually form a thick thatch that will interfere with water absorption and plant growth. If a lawn is mowed regularly enough, it should never be necessary to power rack.
Regular mowing is very effective in controlling weeds. For weeds like quack grass, regular mowing is the only practical control method. Lawn species are well adapted to thrive at a constant height of 1 to 2 inches. Quack grass and many other weeds are not. I will deal with this in more detail under the heading of Weed Control.
Regular mowing is also essential for the development of turf that is dense and thick. Individual grass plants that are allowed to grow to their ultimate height of 6 to 10 inches will have only a few shoots. If they are consistently limited to a height of 1.5 to 2.5 inches they will have many shoots and the overall result will be a turf that is very dense in terms of shoots per square inch. Severe mowing that removes more than a third of the leaf area is very harmful. The shock to individual grass plants is so severe that entire lawns may turn yellow for a week or more while the plants regain their equilibrium. During this time, there is very little growth. If this happens a number of times during the summer, the shoot density will be low enough to expose small areas of soil to the sun providing a window of opportunity for weeds to establish.
Mowing height is a matter of considerable controversy. It is well known that a high mowing height of 1.5 to 2.5 inches results in a lawn which is more deeply rooted and thus more tolerant of drought and more resistant to the intense heat of mid summer. However, in small yards, the lawn simply does not look well manicured unless it is cut to a height of 1 to 1.5 inches. Such a low mowing height is just fine provided that the mowing and watering are regular enough. If you are adjusting the cutting height of a new mower for the first time, lay a short block of 2 x 4 wood on the grass. When you step on it, it should be about flush with the freshly cut lawn.
Thus the clear, tasteless, and odourless liquid which we usually take for granted is nothing less than a magical potion. Without water there is no life.
Plants cannot go to the fridge or the garden faucet for a drink when they are thirsty. They are, however, very well adapted to thrive in widely varying moisture conditions. A lawn that is properly grown will have roots that reach deep into the soil for the water they need. The deeper the roots extend the larger the reservoir of water that is available to them. A lawn with deep roots can survive the extreme summer heat and even continue to thrive. A lawn with shallow roots is very vulnerable in the same circumstance.
Deep rooting is easily encouraged by deep watering at intervals of 7 days or more. Except in conditions of extreme heat most lawns will do very nicely with waterings as infrequent as very 14 days. There are a number of reasons for this phenomenon. Infrequent watering implies lots of time for drying and, consequently, air infiltration into the soil between waterings. In urban yards, poor root development is often caused by inadequate aeration. The roots cannot go down because there is no oxygen there.
We all learned about photosynthesis in high school. Green tissue, in the presence of light, absorbs carbon dioxide and releases oxygen. The reverse of this equation is seldom appreciated. Green tissue, in the absence of light, or any living tissue which is not green absorbs oxygen and releases carbon dioxide. This process is known to biologists as respiration. Plant roots need oxygen just as surely as people do.
Overwatering or watering too frequently has the effect of depriving the plant roots of oxygen. Oxygen stress is indeed a killer. The grass plants cannot live if the roots are deprived of oxygen for too long. The lawn will not bounce back from this kind of stress because there are insufficient roots left to support growth. In an effort to adapt, the roots will grow close to the surface where the oxygen stress is less severe.
Inadequate drainage is closely related to overwatering. Grasses will not thrive in areas that are under ponds of water or wet and soggy much of the time. A slope of 1% is minimal and 2% is much better. This means that you should have a 1 to 2 foot drop for every 100 feet of distance or 1 to 2 centimetres for every meter of distance.
Like most plants, turf grass has the ability to regulate its water use. When water is in short supply, the growth processes slow down. The small pores, or stomata, in the leaves literally close and the plant goes into survival mode. Although it stops growing for the time being, its water requirements are greatly reduced. When the weather is hot, every grass plant in your lawn will grow for a few hours in the morning, switch to survival mode when the sun is high, and then revert back to active growth for a few hours in the evening. This is normal and healthy. When there is a lack of water in the soil the proportionate length of the survival mode is simply extended. No real damage is done except that you don't have to mow quite as often. Grass plants which suffer mild drought stress occasionally will have thicker cuticles, heavier cell walls, and a more extensive root system.
Of course, if the drought stress is severe or prolonged, there may not be enough growth to keep the lawn green and fresh. As the individual grass plants wilt the lawn takes on a blue or grey hue. From this stage a healthy lawn will bounce back within 24 hours of a thorough watering. However, if the drought is allowed to continue, the individual plants will direct what moisture is available to the newest, most central shoots allowing the older blades to whither and die. Even at this stage there is practically no permanent harm. A couple of waterings and a couple of weeks of good growing weather and the lawn will be as green and nice as it ever was.
In summary, avoid overwatering or watering too frequently. In clay soils, this results in continual water saturation. The water fills all the small spaces in the soil leaving little room for air which is absolutely essential for root growth and for the health of the microorganisms. In sandy soils, excess water can actually leach the nutrients and other organic compounds out of the root zone. Under watering does not damage the soil except in rare instances where a small area might be robbed of all natural precipitation by building overhangs and other structures.
Avoid watering too early in the spring. Growth in the spring is usually limited by low soil temperatures and poor aeration, not by a shortage of water. Watering in April or May inhibits soil warming and aeration and is usually self defeating. If you can find any moisture at all when digging in the top 2 inches of soil with a small trowel or table knife, watering in the early spring will do more harm than good. Although watering washes down some of the winter dust it will certainly not speed the greening of your lawn.
An actively growing lawn can easily use a half inch of water or more per week when the weather is warm. How can this water be efficiently replenished? How much water is this? Let's start with the second question. Assume that the average front lawn measures 25 feet by 40 feet. This volume of water, 25 feet x 40 feet x 0.5 inches, works out to about 260 gallons. If your sprinkler puts out 3 gallons per minute, it will need to operate about 1.5 hours. However, a significant part of this water may evaporate before it soaks into the soil and some of it will land outside the target area. When you add a back yard that is probably twice as large and possibly a side yard, it becomes apparent that a single water sprinkler might be required to operate a minimum of 6 hours per week. Not just any sprinkler will do.
It is important that the sprinkler be precise in its pattern, have a uniform application rate over the wetted area, and produce fairly large droplets that reduce evaporation and are less prone to drift in the wind. Unfortunately, most of the sprinklers on the chain store shelves simply do not measure up. Even if you are in the market for only one portable sprinkler, a trip to one of the professional underground irrigation companies listed in your local yellow pages is worth while. My favourite sprinkler is a brass impact sprinkler--the Rainbird 25PJ. Some of the precision plastic impact sprinklers with interchangeable nozzles are also quite good. These sprinklers all have 1/4 to 3/4 and full circle capability which is especially useful when starting a lawn from seed because they can water large areas from the edge. There is no need to walk on freshly watered seed areas.
The ideal solution is a well designed automatic underground irrigation system. Uniform coverage is easily achieved if the design is correct. It is possible to water during the cool of the early morning when there is little wind and evaporation is greatly reduced. An automatic system allows you to set the actual watering duration precisely. An underground system that is not automatic has a tendency to waste a lot of water because it is so easy to forget to turn it off. If your budget is tight, consider starting your lawn from seed instead of sod and applying the savings toward the price of an underground system.
For many soils, the long range impact heads are much better than the smaller range spray heads because the rate of precipitation is much lower. If you are working with clay soil or have significant slopes, a precipitation rate over 1/2 inch per hour is too high. The water will run off rather than soaking into the soil. However, for small or irregular areas, the short range spray heads may be the only option. With an automatic system, you can schedule two short waterings in close succession rather than a single longer watering to minimize the run off problem.
Whether you are watering with a single sprinkler or with an automated system, check the uniformity and the precipitation rate by placing empty food tins on your lawn. Measure the depth of water that accumulates in each tin.
One half inch of water per week is a good starting point. Observe your lawn. The objective is to provide enough water to keep the lawn happy but not a lot more. The first sign of water stress is a phenomenon that the greens keepers at golf courses refer to foot printing. At this stage of water stress, footprints on the lawn will remain visible for a period of time because the grass blades are slow to stand back up. As the water deficit becomes more severe, large sections of the lawn will develop the greyish or bluish tinge that is characteristic of wilting. The lawn will bounce back from this level of drought stress within 24 hours of a thorough watering. These symptoms are a signal that watering needs to be increased a little. With an automatic system this is easy to do because it is simply a matter of increasing the time on each zone slightly until the optimal amount of water is determined. If the weather is unusually hot, increase the zone times slightly. If it is unusually cool or cloudy, decrease the zone times a little. An automatic system will greatly reduce the total water consumption and at the same time insure a lawn that is lush and green.
Do not water everyday. Although an automatic system makes this easy and many "professionals" recommend it, it will not be good for your lawn. Twice a week in hot weather is OK, but once per week is always best. Watering too frequently will result in shallow roots, compacted soil, unusual weed problems, and a lawn that is too soft to withstand normal usage.
The whole issue of "quackgrass as a weed" is a perfect example of the benefits of working with nature rather than against it. When we provide a "quack grass environment" we should expect quackgrass. When we provide a "bluegrass environment" we may logically expect bluegrass.
Have you ever noticed that all crappy lawns have lots of quackgrass and all great lawns have none? Is the abundance of quackgrass the cause of the crappy lawn or is it the result? Think again. If all the quackgrass could be magically removed, would the crappy lawn be a great lawn? Not likely. It would still be a crappy lawn.
Quackgrass is an opportunistic species. Seeds are everywhere because they blow with the drifting snow. They have the ability to remain dormant for a long time and then germinate and grow quickly. Quackgrass is better adapted to survive conditions of drought, low fertility, and soil compaction than any of the premium turf grass cultivars. If not mowed, it grows quickly to a height of about 3 feet and then maintains its advantage by shading its potential competition--a little like the biggest kid getting all the candy because she has the longest reach.
Herein lies the secret of control. Bluegrass cultivars have a much higher shoot density and are much better adapted to continual close mowing. If the bluegrass is thriving and the mowing is frequent enough to keep the quackgrass from getting more of the available sunlight than its little cousins, the quackgrass will simply melt away--really! I have seen this many times, in small home owners yards and in 100 acre turf fields. The quackgrass grows much more quickly than most lawn grasses, especially in the spring. To be successful the mowing must be regular enough to keep the quackgrass from ever getting much taller than the more desirable grasses. The turf grass must be thriving as well. If it is thin, the quackgrass will simply become prostrate to avoid the mower and continue to persist. In other words, all the cultural requirements must be right.
I can hear the sceptics now. "If you mow your lawn everyday, you won't be able to see the quackgrass but that doesn't mean it isn't there." Many home owners have been amazed at how easy it is to get rid of quackgrass in the lawn. Others have told me that its a nice thought but that it simply doesn't work. This puzzles me. When I seeded my present lawn, there was hardly a square foot that did not have quackgrass. Within one year, I could forget about my lawn for 2 weeks and be hard put to find a single blade of quackgrass. I strongly suspect that the occasional lack of success has something to do with the turf grass species that are being cultured to compete with the quackgrass. Bluegrass cultivars are very strong competitors whereas the fescues and other species that are commonly used for non irrigated lawns do not compete nearly as well. More about this under Starting with Seed.
Quackgrass is not the same as Crabgrass. The names "Crabgrass" and "Quackgrass" are sometimes used interchangeably. This is wrong. Crabgrass is an annual plant that comes every year from seed and is not found in our area. We do, however, have a close relative-- Barnyard Grass, which is also an annual. It is a very course grass which is found in areas of high fertility and moisture. It is never a significant problem in cultured lawn areas. Although we do not have Crabgrass on the prairies, we do have Crabgrass Killer on our Garden Centre shelves. I presume it is intended for export to our friends in Ontario and British Columbia! It will not work on Quackgrass.
ANNUAL BLUEGRASS (Poa Annua)
Annual bluegrass seeds seem to be everywhere. When the conditions are right for them, they predominate. The most common cause of an Annual Bluegrass problem is daily watering. As the name implies, most Annual Bluegrass comes from seed every year. The seeds need continual moisture to germinate. The plants themselves are very shallow rooted. When the surface and the top inch or two of the soil are continually wet the Annual Bluegrass can easily predominate. While the deep rooted Kentucky Bluegrass is languishing from conditions of poor aeration, the Annual Bluegrass is happily taking over.
Once you know what to look for, it is easy to recognize an Annual Bluegrass problem. The most obvious clue is the seeds which form in spite of regular mowing. The Bluegrasses and Fescues will not set seed unless they are allowed to grow to their full height of 6 inches or more. At this stage, the problem will simply go away if you adjust your watering schedule to only once per week and possibly twice per week during extremely hot weather. As the Annual Bluegrass establishes over a period of 2 or 3 summers, it results in a very blotchy lawn. Large irregular patches are now pure Annual Bluegrass and the remaining areas have been partially invaded. At this stage the problem is much more difficult to handle.
There are herbicides which are designed to kill germinating seeds but not harm perennial plants such as Kentucky Bluegrass too much. Some of these are the "Crabgrass Killers". In theory they should work but I doubt the practicality of their use. I would prefer to correct the cultural practices and let nature's pendulum swing back the other way.
An Annual Bluegrass problem is a classical example of the human tendency to manipulate nature without understanding what is really happening. An Annual Bluegrass problem is simply a case of the darn stuff growing because someone has provided the exact right (or natural) environment for it. Even with your lawn, there comes a stage at which more intensive culture becomes self defeating.
Dandelions are biennial. The seeds which can drift for miles on a windy day usually germinate in the spring. During the first year they grow in among the grass plants and are barely noticeable. The plants are small; the leaves are quite narrow; and they usually do not flower. They then survive the winter under the ground as a long carrot shaped tap root. The following spring they start their growth quickly, often well ahead of the turf grass. Even under regular close mowing, they manage to flower for most of the summer. I refuse to get upset by a few dandelions, choosing instead to marvel at their unique ability to be everywhere in spite of our best efforts.
If there are only a few dandelions, they are easily removed with a small trowel or "dandelion fork". It is important to cut the root at least 2 or 3 inches below the soil to prevent its regrowth. If there are many dandelions, it may be necessary to resort to chemical control. The chemical herbicide of choice will probably be 2,4-D, dicamba, mecoprop (MCPP), silvex, or a combination of these.
To my neighbours' consternation, I am presently conducting an experiment with Dandelions in my front lawn. The lawn was started from seed with no preplanting weed control and is now almost 5 years old. I still think that ALL the dandelions will disappear but it hasn't happened yet. They are much fewer though. A number of times, I have heard, "Your lawn is so nice. Why don't you spray out the Dandelions?" My obstinate answer is, "Why should I? It's nice enough."
Try pruning some low branches to admit some light and air movement. Reroute the rain spout to another area where the light levels are high enough to allow the grass plants to compete with the Chickweed.
Chemical herbicides fall into two general categories: selective and non selective. Most of the selective herbicides are very harmful to broadleaf plants and much less harmful to narrow leafed grassy plants. Some are selective against germinating seeds while leaving existing plants relatively unharmed. The most common selective herbicides for home owner use are 2,4-D, dicamba, mecoprop, and silvex. They are often available in combination. Non selective herbicides kill everything green. The most common examples are Roundup and Gramoxone. Either one will kill your entire lawn. They are not at all selective.
Chemical herbicides come in various forms. "Weed and Feed" is a mixture of granular fertilizer and herbicide. It is simply broadcast over the lawn just as you would apply fertilizer alone. Although repeat applications are sometimes necessary, it will control most broadleaf weeds. The "Weedbar" is another common method of herbicide application. The chemical herbicide is embedded in a wax bar which is simply dragged across the weedy areas. Although repeat applications will probably be necessary, the weed bar is probably the safest way to apply the broadleaf herbicides to small areas of lawn. There is no possibility of desirable plants being damaged by chemical drift. It is also the safest for the gardener.
The most efficient method of applying chemical herbicides, however, is in the form of a foliar spray. A common product which is effective against most broadleaf weeds is "Killex". It is effective against all broadleaf weeds and relatively inexpensive. Foliar spray herbicides need to be applied as a light spray on the leaves. Attachments that fit on the end of your garden hose do not work well. Metering is not accurate and usually more herbicide is washed off the leaves than is deposited.
For small quantities, a small (1 litre) hand held spray bottle or mister is fine. Set the spray pattern for quite course droplets to avoid the fine mist that is easily inhaled or carried by a slight breeze. For larger jobs, a 3 to 15 litre pressure sprayer is recommended. Again, when pumping it up, keep the pressure as low as possible to avoid the fine mist. For larger yards and acreages, the ideal unit is a backpack sprayer with a lever pump on the side. These units are very efficient and will last a lifetime if properly maintained. Be sure to wash your sprayer thoroughly after each use and avoid using the same sprayer for herbicides and insecticides. This practice is a disaster waiting to happen.
A BAD STORY
"Oh, by the way, we sprayed for dandelions last month. Do you think we could have made the solution too strong?"
He had used a non selective herbicide to kill his dandelions. How could such a thing happen? What had gone wrong? It's a long list:
The theft of the herbicide was the smallest crime!
Start by looking at the basics. Has the watering, mowing, and fertilizer been right? If the answer is honestly yes, it gets a little tougher. Is there a problem with the soil? Perhaps a soil test is in order. Could the lawn have been watered with softened water? A soil test will show this also. Is there just too much traffic? Remember though that even football and soccer fields grow quite well. How are the weeds doing? Knotweed can be symptomatic of too much compaction. Chickweed can be symptomatic of too much water. Is there enough light? For turf grass to thrive, it needs at least two hours of direct sunlight per day or almost continual mottled light. What are the varieties of grass growing or more correctly, not growing so well? If 75 per cent or so is turf grass, the lawn should respond very positively to improved cultural practices.
Providing the lawn is reasonably level and the slopes are OK, it is usually much quicker and more cost effective to simply start caring for the old lawn rather than to replacing it. It never makes any sense to replace a lawn because of a weed problem--not even quackgrass.
If you still want to replace your lawn, it is important to kill the existing one. Although this can be done by cultivation over a period of a few months, it usually makes a lot more sense to spray it with Roundup. Roundup is a slow acting systemic herbicide that is totally effective. If you get 100 per cent coverage, you will get 100 per cent kill including all the underground parts. Seeds which have not germinated yet will, however, survive. After the required waiting period of 7 to 14 days, rototill the entire area before any relevelling is done. If the soil is very clumpy, it may be necessary to water it, let it decompose for a while, and then till it again. Sometimes, it is helpful to actually remove the old sod and haul it away but I am always very reluctant to do this because it results in lost organic matter and nutrients.
Now, the rebuilding begins. You have a choice of Seed or Sod.
Furthermore, the seeding process usually results in a better end product than does the sodding process. When you seed, the lawn usually turns out to be a little smoother because sod is rarely perfectly uniform in thickness and quality. When you seed, you can select the seed varieties that are right for your situation. When I was in the commercial sod business, I often found myself wondering why home owners whose budget was already stretched to the limit would pay us hundreds of dollars for sod when they could easily achieve the same result with seed. The main reason, I concluded, was that they simply did not know how. I will try to explain the process in adequate detail.
Let's start with seed selection. Some of the major seed companies have suggested that a premium lawn should be completely redone every 8 to 10 years. This sounds a little onerous to me! I like to think in terms of doing it right once--not every 10 years! There are some cultivars that perform exceedingly well--for a few years. An excellent example of this is a variety called Merion Kentucky Bluegrass. At one time it was recommended by most prairie experts. It usually developed into the "best lawn on the block" and then began to deteriorate. Today it is not on the recommended list for our area.
On the other end of the spectrum is the large lawn areas at the Saskatoon Zoo (formerly the Forestry Farm Park). These lawns were seeded about 80 years ago. They have always been high traffic areas. They have never been "pampered". And yet, they are as functional and beautiful today as they ever were. The seed variety was almost certainly something known as Common Kentucky Bluegrass. If that seed was available today, I would recommend it without hesitation or reservation of any kind. Unfortunately, the seed market has changed. Today, any Bluegrass Cultivar that meets minimum purity standards can be sold as Common Kentucky Bluegrass. For this reason, I would avoid Common Kentucky Bluegrass.
Today, there are many custom blends of lawn seed available. Many packages of seed have an appealing photograph of a beautiful yard but no information as to what varieties have been included in the blend or what the proportions are. Avoid these like the plague. They may not be suitable for our area or, worse yet, they may be seed surpluses that could not be sold to more discriminating customers. Custom blends that are properly labelled and sold by a reputable seed dealer are just fine. Make sure the blend is right for your purposes. The seed specifications for a not irrigated farmyard or acreage are much different than the specifications for a small, intensively maintained, high traffic urban lawn. Beware of special mixtures for shady areas. Some grasses do perform better in the shade but the difference is very very small. Generally speaking, if your area is too shady for one type of grass, it is too shady for all types of grass.
The only grasses to consider for our climatic zones (2 and 3) are in the Kentucky Bluegrass and Red Fescue families. Let's dispense with the myths first. Red Fescue is not red and Kentucky Bluegrass is not blue, nor does it have a blue tinge. Although Red Fescue is often referred to as Creeping Red Fescue, it does not "creep" nearly as strongly as Kentucky Bluegrass. The "creeping" habit is descriptive of these plants ability to self propagate sideways by means of lateral underground roots which are called rhizomes. It is not uncommon for sod customers to mistake the long white roots which are sometimes visible on the underside of turf pieces for Quackgrass roots. They function in exactly the same way.
Bluegrass and Fescue seeds are often mixed together. This is almost always the case with commercial sod. The sod farmers like the Fescue because it germinates and establishes very quickly and they like the Bluegrass because of its ability to form a sod which is very strong and tear resistant for ease of handling. Although these grasses are compatible, the lawn will usually develop into a monoculture within a year or two. The Fescue will predominate in areas of low fertility, low moisture, and shade. The Bluegrass will predominate in areas of more intensive culture--areas of adequate fertility, moisture, and sunlight.
Cultivar test plots of the various cultivars of Red Fescue and Kentucky Bluegrass are maintained in the Saskatoon area by both Canada Agriculture and the University of Saskatchewan Horticultural Department. The cultivars are evaluated on a regular basis for colour, shoot density, disease resistance, and overall appearance. Although the maintenance on these plots is minimal, the Bluegrasses almost always out perform the Fescues in all categories. The Kentucky Bluegrass cultivars are definitely better suited for the irrigated residential lawn. But which one?
Today, there are at least 50 cultivars of Kentucky Bluegrass on the market. Their success in regional trials varies significantly. The top rated cultivars in Winnipeg are not the same as the top rated cultivars in Saskatoon or Agassiz. Furthermore, the top rated cultivars may not be the same from spring to fall or from year to year. They also vary in their resistance to various diseases. For these reasons, it is a good plan to select a minimum of 3 and preferably 4 or 5 of the following cultivars and mix them together in equal parts: Adelphi, Baron, Birka, Fylking, Majestic, Nugget, and Sydsport. Although these special varieties are expensive, remember that you only need a few pounds.
Seeding rate is also a matter of considerable confusion. The seeds of the Kentucky Bluegrasses are very small. Typically, there are about 2,200,000 seeds per pound. When you do the math, 1 pound per 1000 square feet translates into about 15 seeds per square inch. With a 75 per cent germination rate, which is a reasonable expectation, this is already 3 times as much seed as is required to produce a very dense lawn. In fact, the lawn will actually take longer to establish if the initial density is too high. The trick is to spread the seed as evenly as possible.
Thus, when using pure a blend of pure Kentucky Bluegrass, a seeding rate of 1 pound per 1000 square feet is more than adequate. A little more is OK but definitely not necessary. Unfortunately, you will find "recommended rates" ranging from 3 to 7 pounds per 1000 square feet. When using Kentucky Bluegrass, these high rates are not necessary and may indeed slow down the establishment of your new lawn. It should be noted though, that the seeds of Red Fescue and some of the other grasses which are normally associated with non irrigated lawns are much larger. A pound of Red Fescue seed contains only about 600,000 seeds which is about 1/3 of the number of seeds in a pound of Kentucky Bluegrass. If you are using a portion of Fescue in your blend, which I do not recommend, a higher seeding rate is in order.
Let's get back to the dirt. The grade, a fancy word for describing the slopes, must be correct. The surface must slope away from the house and any other buildings on the property. There must be a drainage route for every square foot of your yard. We all know that water runs down hill but we sometimes don't recognize the low spots until they are hard to correct because they have already been incorporated into the finished landscape. Try to achieve at least a 2 per cent slope for all surfaces except the sidewalks and driveways. For these a slope of as little as 1 per cent is acceptable. A 1 per cent slope means a drop of 1 inch for every 100 inches of distance or 1 foot for every 100 feet of distance. The slope is easily checked with a string level or an ordinary carpenters level on a straight piece of 2 x 4 lumber.
Slopes which are exactly constant are very difficult to achieve and seldom look right. A front lawn which is slightly convex, or rounded up, always looks better than a slope which is exactly straight or concave. Hopefully, you were left with a slope which is nearly correct by the building contractor or the operator who levelled your subgrade and topsoil. If not, it may be necessary to hire a bobcat to come back and do the rough levelling again. Now the hand work begins.
The fine levelling process is not very difficult. People often say, "I was just starting to get good at it and it was done!" The surface must be loose enough to move about with a hand rake. Begin by raking off the stones, indestructible lumps, and other debris. Look for low spots where water might pond. Fill these in by raking soil from the high spots. It is useful to get down low and sight along the surface of the soil from many different directions. At this stage a 42 inch landscape rake or some sort of a "drag" device is helpful because it is much wider than the garden rake. If you can rent or borrow a landscape rake, great. Do not, however, go our and buy one because it will cost about $100.00 and you will probably never need it again. A simple drag device can be made from just about anything that is about 5 feet long, reasonably straight, and heavy enough to engage the soil a little. A short piece of an old wooden ladder is ideal. Simply attach a rope to each end and drag it over the surface of the soil with the 2 x 4 sides down. Weigh it down a little or have a friend apply some downward pressure with a rake while you are dragging it. Just a few passes will make you feel like a real craftsman. If there is a little loose soil to move around, the surface becomes perfectly level is no time at all. Check again for low spots and repeat as necessary.
The soil surface should be about 1/2 inch lower than adjacent sidewalks and driveways. After the lawn establishes itself, it will be flush.
Do not buy, rent, or borrow a roller. It is not necessary. Secondly, do not rototill or otherwise cultivate the site any more than is necessary. A seed bed of small lumps (1/4 to 1 inch) is much better than a seed bed that is very fine and pulverized. It provides lots of small crevices to hold the seeds and to stabilize the surface so the seeds don't blow or wash away. The seedbed should be firm--when you walk on it, the footprints should be less than 1/2 inch deep. Usually this firmness is not hard to achieve. By the time the levelling process is complete the necessary firmness has usually been achieved. If the levelling process is almost complete and the surface is still too soft, give it a good watering, let is dry for a day, and finish the job. This is much more effective than rolling and requires a lot less effort.
Now, it is time to spread the seed. Work when the weather is calm. Even a slight breeze will carry the fine seed a long ways. Begin by drawing the outline of the lawn area in the soil with the handle of the rake. For relatively small areas, the seed can easily be spread by hand, without any equipment at all. Simply take a small handful of seed and let it sift through your fingers as you walk about the area. The trick is to keep your hand high, at least waist height, and let the seed spread naturally as it falls. Take your time. Start by spreading the seed very lightly and keep working until the seed is almost all gone. Save just a little in case you need to do some touch up seeding in two or three weeks.
For larger areas, the small hand held whirly bird spreaders or the larger shoulder bag ones described in the fertilizer section work well. The traditional hopper spreaders which are ground driven are almost useless for seeding the fine grasses. They are not very precise and quite cumbersome.
Rake in the seed with a spring tine leaf rack. Although a normal garden rake will do the job, it has a tendency to disturb the soil too much and actually distort the seed pattern. I like to think of this process in terms of "hiding" the seed just a little. Simply walk briskly dragging the rake beside you with a moderate downward pressure. Rake out your footprints as you go. Sometimes, a second pass at right angles is useful. The goal is to "hide" a percentage of the seed within the top 1/4 inch of the soil. Do not be disturbed by the seed which is still visible.
Begin watering immediately. Water as deeply as you can without washing out the seed. With an automatic underground system, this is easy. Otherwise, impact sprinklers with 1/4 or 1/2 circle capability work well. If the area is large, you might consider putting a sprinkler in the middle and leaving it there until the grass germinates. You don't want deep foot prints in the freshly water seedbed. Always water until the surface just becomes shiny. Depending on the soil type and the precipitation rate of your sprinkler, this could be anywhere from 20 minutes to several hours. The goal is to thoroughly wet the soil to a depth of at least 4 or 5 inches. It may be necessary to water repeatedly for short intervals to a achieve this goal. After that a light top up watering every morning is adequate to achieve quick and uniform germination.
Bluegrasses will germinate in 2 to 3 weeks depending on the soil temperature. Do not even think about reseeding or touch up for at least 3 weeks. Usually even areas that seem to have all the seed washed out will have enough seed left to produce a very fine lawn. Small bare areas will fill in very quickly. If some reseeding is necessary, simply rough the area up a little with a garden rake and spread the little bit of seed which you saved for this purpose. Sometimes, it is easier to mix the touch up seed with a little fine topsoil and then spread this mixture over any bare areas which are slow to develop.
Start mowing as soon as the grass seedlings or in some cases, the weeds, reach a height of 2 to 3 inches. Mow regularly. Do not worry about the weeds for at least three months. By that time, there will probably be no weeds left to worry about. Sometimes, depending on the time of year you are seeding, it seems that all you are getting is weeds. This is OK. The weeds are actually your friends because they stabilize the surface and protect the tiny seedlings. With regular mowing, they will simply melt away. As the lawn develops change your maintenance practices to those described in the earlier sections of this article.
Although seeding can be done any time that the soil is not frozen, some times are better than others. Avoid seeding before the third week in May. Germination will be slow because of low soil temperatures. Avoid seeding after September 15 because the lawn will not have time to stabilize the soil surface very well before freeze up.
Seeding does require a little patience and a little faith but the results can be very gratifying.
Sod has the advantage of stabilizing the soil instantly and then establishing in 1 to 2 weeks rather than the 3 to 4 weeks that it takes for seed to establish. Sod is never blown away by the wind or washed out by heavy rains.
Sod selection is greatly simplified because there are rarely more than 2 or 3 suppliers to choose from. Do not make your selection on the basis of price alone. What is the seed blend? If the salesperson doesn't know or is reluctant tell you, be aware. Was the seed blend selected because it was cheap; because it was easy to start; because it produces a high strength sod; or because it will produce a high quality long lasting lawn with good disease resistance and easy maintenance characteristics? Will the sod be delivered fresh? Will the pieces be uniformly cut? Will the sod be weed free? Don't be shy about asking these questions. Probably the best way to evaluate potential suppliers is to check out recent sod deliveries in your area. Ask around.
Contrary to popular belief, thinly cut sod is better providing it does not have holes or frayed edges. Although thinly cut sod will dry out a little faster, it is much easier to handle, will shrink less, and will root more quickly.
Think twice about hauling your own sod. Few pick up trucks or utility trailers will safely haul more than 300 square feet. Sod is very heavy.
Measure carefully. It is hard to dispose of excess sod. Order exactly what you need. Usually the sod will go a little further than you expect. Do not order until your site is completely ready. Sod is very perishable and will not last more than a day or two on the pallet without deteriorating badly.
Sod bed preparation is exactly the same as seed bed preparation except that the edges adjacent to walks and driveways should be down about 1 to 1 1/2 inches to allow for the thickness of the sod. If the finished lawn is a little lower than the adjacent hard surface, that is just fine. It will fill in soon enough. If the top inch or so of the sod bed is fairly soft the sod will settle in better and the finished lawn will be smoother.
OK, it's time to put down the sod. Stagger the joints as a bricklayer would. Avoid putting small pieces at the edge. It is better to use them up in the middle somewhere. Make sure the pieces are pulled together tightly. If there are gaps, your lawn mower wheels will surely find them. The sod is easily cut with a replaceable blade utility knife or with a sharp hooked linoleum knife. Kitchen knives and sharpened spades do not work very well. If there is a lot of trimming, lay the odd shaped pieces on the turf black side up. That way, it is much easier to find the right piece for filling in here and there.
Start watering immediately. If it is a hot or windy day, you should be hosing down the sod before you are even finished the job. Water deeply. The soil below the turf should be wet to a depth of at least 3 or 4 inches. Do not let the sod dry out. It will turn brown and go dormant very easily. When this happens, it will take weeks to come back. Water daily until the sod is well rooted. In warm weather, this will take about a week. Start mowing as soon as there is significant growth. After 2 weeks, start treating it as you would a regular lawn.
Sod can be installed any time that the ground is not frozen. However, there is not much point in laying the sod before the third week in May because it simply won't root until the ground warms up. Similarly, late fall installations will just lay there until the ground warms up the following spring. Although the mud and dust will be under control the pieces are vulnerable until they establish.
There is a lot of controversy about rolling the lawn. With very few exceptions the rolling does more harm than good. It is sometimes argued that rolling improves the contact between the sod and the soil and that it helps to level the finished lawn by compressing the uneven sod pieces into a smooth surface. I think both of these arguments are usually advanced by people who haven't tried it. As you water the sod, it becomes very heavy and limp. Contact with the soil happens all by itself. The levelling effect will not be significant unless the site is very wet and soft. Under these conditions the roller and the person pulling it will create more non-uniformities than they fix.
It is not necessary to stay off the new lawn except when it is very wet and soft. In fact, moderate use is probably the best thing for it. Even during installation, experienced installers will often start closest to the pallets of sod and carry the pieces over the freshly laid turf. Providing you don't kick the pieces out of place, this does no harm. If sod is installed fresh and not allowed to dry out, it is practically fail safe.