Turfgrass Lawn Maintenance

Turfgrass lawn maintenance requires fertilizer, mowing, and the right grass seed.

Grass Seeds

Grass seeds

Photo By Shutterstock/Gunnar Pippel

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Whether it be from our ancient history roaming grassy savannas or traced back to the managed meadows of medieval castles and manors, one thing is certain: Mankind has a love affair with lawns.

In 2002, the U.S. turfgrass industry estimated the total economic impact of the turfgrass (lawn) industry to be $57.9 billion dollars; that’s a lot of grass seed and fertilizer. Not to mention pesticides and herbicides, which are under constant scrutiny for their potentially harmful effects on animals and humans alike. This begs the question of what does this controlled ecosystem in our front yards really require? What fuels it, and how can I make the most of mine without breaking the bank or creating a biodynamic desert with harsh chemicals?

To truly understand how to grow a beautiful and healthy lawn, we first need to understand at least a little about the plant making up the majority of modern lawns. These plants all belong to a family of grasses collectively known as turfgrass. They are given this name because of their tendency, under healthy conditions, to form “turf,” which is the dense growth of grass, roots and earth that makes up the typical lawn. Imagine a slab of sod.

There are different strains, some of which do best in cooler climates with lots of rainfall, others that prefer less fertile soil and hot, dry summers. All are capable of self-propagating, or essentially cloning themselves, by means of runners that grow out either above ground (stolons) or below ground (rhizomes) from the base of the plant. As with all grasses, the turfgrass plants require high levels of nitrogen, and most have high water requirements as well. If we can account for these basic needs, our lawns will thrive and be as green as our neighbors’ envy.

Choosing the right turfgrass

As mentioned previously, there are a number of different turfgrass varieties available today, and while they are generally classified for cool or warm climates, modern grass hybrids and seed blends allow for much greater flexibility when it comes to selecting the right grass for your needs.

The primary cool-climate grasses used are Kentucky bluegrass, perennial ryegrasses, and tall and fine fescues. These grasses can be grown in areas from the prairies to the cold regions of the northern Midwest and even in the cool, arid areas of the Intermountain West as long as irrigation is available. The growth of the cool-season grasses peaks in both spring and fall, with a sort of dormant period of minimal  growth throughout the heat of summer. Understanding this growing pattern is key to effective fertilization.

In the warm parts of the country, especially in the South, other grasses such as Bermuda, zoysia and St. Augustine are the best choices for many people. These grasses are warm-climate tolerant and only actively grow during the hot summer months. During the cooler winter months, they will often go dormant and have a strawlike color to them. Because of this, many Southern homeowners choose to invest in winter overseeding of an annual cool-season grass type, such as annual ryegrass, in order to preserve a green appearance nearly year-round.

Fertilizing

The grasses in our lawns are under continued stress from cutting, trampling and crowding as they form thick sod. It’s because of this that they periodically require additional nutrients to ensure they don’t outgrow the fertility of the soil.

As a general rule of thumb, no more than one to four pounds of a nitrogen fertilizer is needed per 1,000 square feet per season regardless of the type of grass we are growing. The warm-season varieties may require a bit more than the cool-season grasses.

The most important thing to take into consideration with any fertilizer application is to apply it at the right time to make it available to the grass when it is most needed. Understanding the growth cycle of our grass type is key to this timing.

Because cool-season grasses begin actively growing in the early spring and fall seasons, those are the times when the fertilizer can best be used by the lawn. The primary components of fertilizer are nitrogen (N) for leaf growth, phosphorus (P) for vigorous root growth, and potassium (K) to help both with root growth as well as aiding in the plant’s ability to uptake nutrients.

If you use a manufactured fertilizer product, spring fertilizer applications should be of the slow-release type, typically called a water insoluble nitrogen (WIN) fertilizer. These are usually sulfur- or polymer-coated fertilizers with high percentages of nitrogen and oftentimes combined with smaller percentages of phosphorus and potash as well as some iron for keeping the dark green color that we want in our lawns. They will slowly break down and release nutrients into the ground over a longer period of time, usually over eight to 12 weeks. Using a slow-release fertilizer early in the spring will ensure that the cool season lawn has a readily available supply of nutrients during its main growth period. Additional applications of quick-release, or water-soluble fertilizers, can be used later in the spring for a last blast of growth before the grass slows its growth during the summer.

Many homeowners notice that their lawns may seem to slow their growth and may even brown up slightly during the summer. For cool-season grasses, this is normal. Applying more fertilizer at this time can cause stress to a lawn by making it want to grow against its natural life cycle. Additionally, much of the fertilizer applied at this time will not be used by the grass and can leach into groundwater and cause serious environmental problems downstream. Worse yet, applying quick-release fertilizers during hot summer months can cause burning and even permanent damage to our lawns.

The second growth cycle for cool-season grasses begins in the fall as the weather begins to turn cool again. This is a good time for another application of a quick-release fertilizer geared not towards leaf growth, but rather to building healthy roots and preparing for the winter dormant cycle. This will help the turf resist disease and damage from the cold winter ahead and give it a good head start for the next season. These balanced fertilizers will have higher levels of P and K than their early season counterparts.

Warm-season grass varieties typically have tropical origins and so are geared to growing in warm weather and often in poor soils. Because their primary growth period is through the hottest parts of the summer, the time when they need fertilization is different than that of the cool-season varieties, although the nutrients are the same.

Fertilizing with a slow-release fertilizer in late spring will get the grass off to a good start, and through the summer another application of a quick-release type can continue to maintain health and appearance.

Fertilizing warm-season grasses should happen no later than early fall, about the time that a winter overseeding takes place. After that time, the cooler weather has signaled the grass to go dormant for the winter, and it will be stressed and susceptible to disease if it is encouraged to continue growing.

Organic fertilizer choices

There are, of course, organic fertilizer options, as well as what I like to think of as systemic methods of increasing and maintaining soil fertility in your lawns.

Organic fertilizers consist of nitrogen found in sources such as plant and animal by-products, rock powders and seaweed, as opposed to the fossil-fuel derived traditional fertilizers.

Another wonderful option that I have used with great success in my own yard is managed animal grazing. In my case, that meant rotating a portable chicken coop around my backyard throughout the spring and fall, allowing the chickens to consume weeds, add nitrogen-rich manure, and scratch and aerate the soil while spreading that manure around for me. I also have had neighbors who have tied horses in their yards for a day or two for the same effect.

Of course, it depends on where you live as to whether these options are possible, but it does bear mentioning as the cost of fertilizers consistently increases from year to year as the cost of the fossil fuels that they are tied to increases.

Another source for lawn fertilization can be from the clippings generated by the consistent mowing and grooming of our lawns. I have read that as much as 30 percent of a lawn’s total nitrogen requirements can be met through allowing clippings to mulch into the soil rather than bagging and removing them.

A primary reason for the removal of clippings is to keep a clean appearance to the turf, free from the straw color of the sun-dried clippings, as well as to prevent thatch buildup in the root zone. Both are legitimate concerns, yet they do not mean that the clippings need to be wasted.

By composting the collected lawn clippings with the addition of some straw, for instance, a high nitrogen compost can be easily generated.

Think of it this way: You are spending a good deal of time and money to grow a luxurious lawn that you are then cutting off and throwing away. All the fertilizer you purchased is going to produce more clippings to fill your garbage can. Seems like a waste, doesn’t it?

The only significant concern with composting lawn clippings comes from the use of broadleaf weed killers, mainly with the spray-on type that could be sitting on the leaves of grass.

If those clippings are composted and used in another application such as a vegetable garden, the weed killer could potentially cause harm or kill the “broadleaf” plants in the garden. After a week or two of mows after weed killer application, the clippings should be perfectly safe to add to the compost pile.

Pest and weed control

Overall, the greatest general deterrent to pests and weeds is a healthy, vigorous lawn that is too dense to allow much growth of weeds and healthy enough to resist disease and infestation from pests. There may well come a time to treat a lawn, however, and by keeping a few simple things in mind you can save a little money and leave a smaller footprint on the planet at the same time.

Weed prevention is one of the main concerns for most homeowners. Because our “managed meadows” have evolved into essentially living carpets, it’s seen as a major detraction to have anything growing within the lawn boundaries that is not of the accepted turfgrass type.

One good way to save a little bit of money on herbicide is to set a realistic expectation. Do you need to treat the small outbreaks of dandelions that pop up every spring, or can you make peace with having a few of them around — or why not just dig them up?

If you are determined to keep as many weed species out of the lawn as possible, I would consider applying a pre-emergent to your lawn as soon as it begins to green up in the spring. Pre-emergents will keep the weed seeds that were dropped the previous summer from germinating causing you to have to deal with them later.

If, or more likely when, you have weeds show up later in the season, you can easily manage them with hand removal or targeted application of an herbicide. When applying herbicides, there is a simple rule of thumb: “The label is the law.” Many lawn owners believe that if some is good, then more must be better. This is not the case with any herbicide or pesticide, and the application rates should be strictly followed.

Mowing

One of the reasons that lawns were originally enjoyed only by the wealthy elite was because the high cost of maintaining the trimmed and well-kept appearance of a lawn required either huge amounts of manual labor to scythe and trim the lawns by hand, or large herds of sheep or other livestock to keep them grazed down to an acceptable level. These problems were largely solved in the early 1800s with the invention of the cylinder or “reel” mower, in which a series of blades rotated against a fixed cutting edge.

By the dawn of the 20th century, pushmower design had been perfected, allowing people who could not have otherwise afforded it to be able to keep a lawn as part of their private homes. The biggest benefits to reel mowers is that they cut the grass similar to the way scissors would and at a very consistent height. Also, when a push style is used, there is no environmental impact, and the activity even provides the pusher with a good workout in the process.

Most common to today’s homeowners, however, is the rotary-style gasoline-powered lawn mowers that spin a sharpened cutting blade underneath a mower deck, essentially mimicking a powered scythe by “whacking” off the tops of the grass. The benefits are that they come in a wide variety of styles, many self-propelled, and they are easy to match a size to your yard. On the downside of these, however, are the perpetual cost of fuel and oil, as well as the higher maintenance cost over the life of the machine. Whichever method is used, there are certain things to keep in mind while mowing a turfgrass.

The act of mowing is, to the grass itself, a double-edged sword. While the cutting provides a neat and trimmed appearance and encourages the growth of lateral runners giving a fuller look and denser feel to the lawn, after grass is cut, root growth is temporarily halted, and the cut end of the leaf allows water to be lost and provides an opening for disease to enter the plant. Because of this, the homeowner needs to be aware whenever mowing of the time of year, the point in the particular variety’s life cycle, and the fertility level of the grass.

During a time of vigorous leaf growth, the grass is actively growing and can recover more quickly, so it is generally OK to use shorter mowing heights. In the case of most cool-season grasses, that means mowing when the blades are 2 to 4 inches tall and cutting them to a height of 1 to 3 inches. While the shorter height provides the grass a catalyst to throw out runners and fill in to a fuller and healthier turf, care should be taken to not cut too much at one time. Frequent cuttings are better than deeper cuttings.

During the warmer months when the grass is growing very slowly, homeowners should use the higher mowing heights. This helps to shade the soil from the heat of the sun, reducing water loss and encouraging root growth throughout the summer. The higher mowing heights also are a good idea, even during vigorous growth, in the more arid parts of the country to build drought tolerance in the lawn.

Warm-season turfgrass, because it’s already more drought-tolerant and in general more hardy, can be mowed to lower heights in general, often as low as 3/4 to 1-1/2 inches. It will be cut again when it has grown to only 1-1/2 to 2-1/4 inches in height. In the case of these grass varieties, the off-growth season is during the cooler winter months and, in many cases, mowing may not be required at all during this time.

The exception to this is in the case of winter overseeded grasses that should be mowed regularly to maintain a well-kept appearance. This is their period of active growth, so mowing can be frequent, but the height should not be kept too low as it is essentially a new lawn.

The mower

A final consideration in the mowing of lawns is the care of the mower itself.

When the blades of a mower are allowed to become dull, they are unable to make a clean cut of the grass blades. This causes a rough edge to be formed at the top of the grass blade that will not only affect the appearance of the lawn, but will open it up to disease as well.

The type of mower you choose to use will determine the maintenance schedule that you will need to work with. For the most common rotary mowers, the blades should be removed and sharpened twice per season, as long as no damage is done to the blade during the season. In that case, a midseason touch-up may be required. It’s not a difficult process — generally one bolt is removed and the blade can be sharpened on a bench grinder or with a heavy-duty metal file.

Reel-style mowers generally only require sharpening once per season. However, there are a number of parts to remove in order to sharpen the blade, and a sharpening kit with a crank and sharpening compound must be purchased.

There are a few basic things to pay attention to when maintaining your lawn, but at the end of the day, it is just a lawn and it wants to grow. More than anything, taking a little bit of time to understand what it is that you’re working with and how best to make it work for you is the best tool you can have in your shed.


Why monoculture may not be best

There was a time when acceptable lawns included a mixture of various grasses and some broadleaf plants as well. In fact, major lawn seed companies once promoted white Dutch clover as a beneficial addition to North American lawns. It not only adds some color, but it adds some nitrogen, too. So what changed, you might wonder?

It turns out that keeping dandelions, thistles, and other showy or tough-to-destroy weeds at bay could be made much easier once selective herbicides came on the scene. Unfortunately, the level of selectivity was not terribly precise. So herbicides that killed dandelions and thistles also killed clovers and creeping thyme and violets – as well as other lovely components of a diverse lawn matrix. So, the very same companies that promoted including white Dutch clover seed for lawns did an about face to make it OK to sell and use the broadleaf herbicides. And now, several generations later, most folks can’t imagine the thought of something like clover contaminating the lawn.

If you live where you don’t need to keep up with the Joneses and you want to experience a beautiful and diversified lawn, throw some white Dutch clover around and see what happens!