If you live in an apartment, you probably don't give much thought to grass. It's just the green backdrop to your on-the-go life.
But as soon as you plop down a deposit on your own piece of suburbia, strange thoughts start running through your mind. In the suburban world, grass seems very important, and you're consumed by its mysteries. Why does your neighbor's lawn glow deep green, like a rolling golf course, while yours withers to a brown mess, overrun by weeds? What makes perfect grass perfect? What do you need to do to maintain a beautiful lawn, short of shelling out hundreds of dollars to a professional lawn care service?
In this edition of HowStuffWorks, we'll find out what grass is, what it needs, and how you can make yours the best on the block. If you don't have your own lawn, or you couldn't care less what it looks like, none of this will seem very important. But if you're up late at night tossing and turning because the grass is greener on the other side of your fence, read on.
What is Grass?
Before we get into the peculiar world of lawn care, let's cover some basics. What exactly is grass?
Grass is the common name for the Gramineae family of plants. With more than 9,000 known species, this family is one of the largest on Earth.
Grass is extremely important to most people's lives, whether they know it or not. For one thing, grass is a major food source all over the world. Rice, corn and oats come from grass plants, for example, and most livestock animals feed primarily on grasses. In some parts of the world, people use grass plants in construction (bamboo is a grass, for example), and wherever it grows, grass plays a vital role in curbing erosion. Grass is also used to make sugar, liquor, bread and plastics, among many other things.
Grasses have a very simple structure, and a very simple way of life. You can better grasp what grass needs when you understand how it actually functions in the world.
At the base of the grass plant, roots grow down into the earth. Typically, grass roots are fibrous, or threadlike. They extend into the soil like fingers, collecting nutrients, soaking up water and securing the plant to the ground.
Grass stems, called culms, grow up from the base of the plant (the crown). In most grass species, the culms are hollow and rigid, except at the nodes -- joints that join stem segments together.
Narrow leaves extend out from the culms, above each node. The leaves alternate in direction. That is, if the first leaf on a culm grows to the right, the second leaf will grow to left and the third leaf will grow to the right and so on.
The lower part of the leaf is called the sheath, and the upper part is called the blade. In most grasses, a ligule surrounds the connection between the sheath and the blade. A ligule can take the form of a thin membrane or a fringe of hair-like projections.
Like the leaves on a tree, grass leaves serve to collect energy from sunlight through photosynthesis. The photosynthesizing chlorophyll in the leaf gives grass its green color.
There are two major methods of reproduction in grasses. Some grasses have additional stems that grow sideways, either below ground or just above it. Stems that creep along the ground are called stolens, and stems that grow below ground are called rhizomes. Grasses use stolens and rhizomes to reach out and establish new grass culms. The stolen or rhizome nurtures the new plant until it is strong enough to survive on its own.
Grasses also have flowers. The small flowers in most grass species are known as florets. Florets grow together in small groups called spikelets, which collectively form inflorescences. Flowers produce the spores that pollinate other flowers, which produce seeds. With any luck, some of the seeds will grow new healthy grass plants. (This site explains grass reproduction in detail.)
In some grasses, such as corn, the stem and the flowering part of the plant are obvious. But in lawn grasses, the long thin leaves overshadow the other elements of the plant. Unless you're up close, all you see is green stalks.
The Basic Elements
So, let's say you want a perfect lawn -- a lawn that looks like a golf course, a nice green carpet surrounding your house. Is this possible?
It's not only possible, it's really not that complicated, at least in most parts of the world. None of the advice that follows will help you grow a luscious lawn at the North Pole or in the middle of the Sahara desert, but it should do the trick in more temperate regions.
Like most plants, grass needs three things to thrive. It needs:
Additionally, it needs be largely free of destructive elements, namely:
If you have the right variety of grass for your area and you meet all these needs, a beautiful lawn should be a cinch. In the next few sections, we'll run down all the major elements involved in healthy grass and outline a course for proper lawn care.
No amount of water and sunlight will make your lawn luscious and green if you have poor soil, so this is a good place to start.
A grass plant's backbone is its root system. The roots soak up water, collect nutrients, anchor the plant and, in some species, spread out to grow new plants. A plant can only do these things effectively if the soil is right.
The soil needs to be loose enough that the grass roots can spread easily, absorbent enough that it will collect water and rich enough that it can provide the plant with nutrients. Roots also need a certain amount of circulating air, which means the soil can't be too compact.
Ideally, you want loam -- soil that has roughly equal amounts of silt, sand and clay (a "perfect" loam is about 40 percent silt, 40 percent sand and only 20 percent clay). Loam is fairly loose, but it has enough clay to absorb water effectively. Check out this page for a simple soil content test.
The soil's pH rating is also important. This rating tells you the relative acidity and alkalinity of the soil (this page explains the concept). The ideal pH level is around 6.5 or 7, but levels vary between different grass species and climate conditions. You can find out your soil's pH level with a home test or a professional test.
If you need to substantially increase the acid level, add sulfur. If you want to reduce the acid level, add lime (this page will give you the details).
To improve your soil, you can amend it with topsoil, compost or fertilizer.
Next to soil, the most important factor in lawn care is the grass species itself. In the next section, we'll see what's involved in picking the right grass.
The Right Grass
To establish a beautiful lawn, you need to choose an appropriate type of grass. There are two major factors in this decision:
Cool-season grasses, such as Kentucky Bluegrass, hold up well to cold winters, but don't do well in very hot weather. Warm-season grasses, such as Bermuda grass, love heat and sunlight. Commercial grass seed is usually a mixture or a blend of species. Mixtures are combinations of different types of grass. The various species all have different strengths and weaknesses, so collectively they hold up to just about anything. Blends are combinations of different varieties of the same type of grass. Blends are not as adaptable as mixtures, but they are generally more attractive because of their uniformity.
- Your local climate (average rainfall, heat, etc.)
- The amount of sunlight your lawn gets
Most grass species need direct sunlight several hours a day to thrive, but you can seed heartier grass that does well in the shade. If your lawn is completely covered in shade, consider another sort of ground cover.
It's also important to pick a species that does well with the amount of water in your area. "Water-loving" grass species will do terribly in drought-prone areas, and some grasses develop fungal disease in very wet areas.
Additionally, consider how you'll treat the grass. Some grasses hold up to heavy traffic and some don't. If you have kids and outdoor pets, you definitely need a resilient mixture.
Check out this site for a general guide to different grasses. For specific advice, check with nurseries and garden centers in your area -- they'll know which grasses do well in the local climate.
Once you've chosen a good grass, you need to decide how to plant it. In the next section, we'll look at the four major planting options.
If you're starting a new lawn from scratch or overhauling an ailing one, you'll need to add grass. There are three ways to go about this:
- Seeding - Planting grass seed in the soil
- Sodding - Laying out chunks of turf containing healthy grass plants
- Adding plugs or sprigs - Transplanting individual grass plants or small sections of grass and soil
The most common method (and the cheapest) is seeding. When planting new seed, select a good species or mix for your area. Look for high-quality seed -- don't go for the cheapest option. Check with a local garden center to find out the best time to seed in your area.
- To seed, first mix any topsoil, fertilizer or compost into your existing soil using a rotary tiller.
- Then use a rake or board scraper to level the soil. This minimizes bumps and holes, which make mowing more difficult.
- Next, scatter the seed, either by hand or with a mechanical spreader. The seed bag should tell you roughly how many seeds to use in a given area.
- Compact the seeds with a lawn roller.
- Rake the seeded area to lightly cover about half the seeds with soil.
- Cover the lawn with a little bit of mulching material, such as straw.
- Soak the seeded area and water regularly until the grass starts to come in.
Sodding is much more expensive than seeding, but you get instant results. With sodding, you can go from an anemic, patchy lawn to a rich green lawn in a day, whereas it may take years for a seeded lawn to grow in completely.
Sod arrives in rolled-up rectangular chunks, about an inch thick. Before you have the sod delivered, you should prepare the soil in the same way you would for seeding. All you have to do when the sod arrives is lay it out over the soil in straight rows. Stagger the sod chunks like you would stagger bricks in a wall. Fill in any gaps between the sod pieces with soil, compact the sod with a lawn roller and you're done. Water the sod regularly until it is well established. It's a good idea not to walk on the sod at first.
Grass sprigs (individual grass plants) and plugs (small sections of soil and grass) are a huge mail-order business. You specify the area of your lawn, and the company sends you the right number of live grass plants. Planting sprigs and plugs gets faster results than seeding, but it is more expensive and takes more work.
To plant sprigs and plugs, prepare the soil just like you were seeding or sodding. Then dig regularly spaced holes (6 to 12 inches / 15 to 30 cm apart, depending on the grass species), fill them with water and insert the plants. Fill in loose soil around the plants and press them into the ground. You have to water regularly and keep weeds at bay while the plants' roots spread in the soil. In mail-order grass, such as Zoysia, the stolens branch out quickly to grow new grass plants.
Watering and Mowing
Finally, we get to the meat of the matter. If you've got the right soil, and you've planted the right grass, how do you keep your lawn mean and green?
There are eight major components to lawn maintenance:
- Fighting weeds
- Fighting pests
- Fighting disease
Watering is simple. The general rule is to water heavily, when the lawn really needs it, rather than watering lightly more frequently. If you water lightly, the water won't make it down into the soil so it won't do much good. You should water enough to soak 6 to 8 inches (15 to 20 cm) deep, encouraging the roots to grow deep into the ground. Watering recommendations vary between different soil types, but as a general rule, water until there is about an inch of water (2.5 cm) over the ground surface.
Water as soon as the grass starts to dry out. Its color will change from green to bluish grey, and it will lose some of its bounce. If the grass doesn't spring back a few seconds after you step on it, it needs water. The best time to water is in the early morning; the water won't evaporate as easily as in the afternoon, and it will cool the lawn down as temperatures start to climb.
Mowing reduces the workload on a grass plant's root system. A large culm above-ground requires more water and nutrients from underground. It's easier for the roots to provide for the plant if the culm is smaller. Mowing also encourages the grass plant to expand. When the blades cut down the leaves, the plant has to grow new leaves to absorb sunlight. This helps build a thicker, heavier lawn, which is more resistant to weeds and disease.
It's best to mow frequently during the growing season. The rule of thumb is to never cut off more than a third of the grass plant at once -- it's bad for the plant to lose a lot of its photosynthesizing ability suddenly. One common mowing mistake is cutting the grass too short. It's best to keep cool-season grasses at about 3 inches (7.5 cm) high or taller, and most warm-season grasses do well at about 2 or 2.5 inches (5 to 6.5 cm) high. You may want to vary the mowing height throughout the year. In fall, winter and spring, you can mow closer because temperatures are cool and water is more abundant. In the summer, let the grass grow longer. The shade will help cool the soil.
Lawn care experts recommend varying your mowing pattern. That is, push the mower north and south one week and east and west the next week. Sharpen your mower blades a couple of times a year to ensure a healthy, clean cut. If you have a mulching mower, you can leave the clippings on the lawn to help fertilize the grass.
In addition to mowing and watering regularly, you'll need to make time for several larger jobs throughout the year.
Fertilizing adds nutrients to the soil so that the soil can provide nutrients to the grass. If you mow regularly, your grass will grow very quickly, which means it needs more nutrients than an average plant. Your soil can provide nutrients for most native plants by itself, but it may need some help to feed your grass.
What's Weed and Feed?
"Weed and feed" products are simply a combination of herbicide chemicals and fertilizer chemicals. These products may contain pre-emergent herbicides, which kill weeds that haven't sprouted yet, or post-emergent herbicides, which kill grown weed plants. Some weed and feed mixtures also contain pesticides. Just like "shampoo and conditioner in one" products, the idea of weed and feed is to cut down on lawn care time by giving you everything you need in one bottle.
Garden experts warn that this usually isn't the best approach to feeding and weeding. For one thing, the optimum fertilizing time is different from the optimum weed-killing time in most areas. More importantly, applying herbicide all over your lawn is overkill when you only have isolated weeds, and the chemicals can damage the environment. In most cases, applying fertilizer, herbicide and pesticide more precisely, when it is needed, is a better lawn care strategy.
The most effective way to fertilize is to spread slow-acting commercial granular fertilizer once or twice a year. Unlike water-soluble spray fertilizer, which acts on the leaves directly, granular fertilizer releases nutrients gradually over several months. If you spread the fertilizer in the fall, it will strengthen the plant's root structure, making it more resilient to drought and more resistant to weeds. You can also add natural fertilizer, such as compost and manure.
When soil gets compacted -- from foot traffic, mowing and the like -- oxygen can't reach the microbes that break down organic matter to enrich the soil. To keep your lawn healthy, it's a good idea to aerate it periodically -- to open up the compacted soil.
Manual and power core-aerators remove narrow sections of soil to form shallow holes. Air, water and organic material spread into the ground through the holes, revitalizing the soil. If heavy traffic compacts your lawn severely, it's best to aerate it every spring or fall.
In any lawn, thatch material collects around the base of the grass plants. Thatch is not made up of mowed grass clippings, as is commonly believed. Clippings usually break down in a week or so. Thatch is actually made up of culms and crowns that have died naturally.
A small amount of thatch helps conserve water in the soil by blocking evaporation, but heavy thatch build-up (more than a quarter-inch / 6 mm thick) keeps air and water from ever reaching the soil. If there's too much thatch on your lawn, rake it up or rent a power de-thatcher.
Weeding is an ongoing process, but it shouldn't take much time once you establish a healthy lawn. Grass, especially modern mixtures, is extremely competitive and will crowd out most weeds itself. If a lot of weeds do pop up, take it as a sign that your grass is weaker than it should be. This could mean your soil is deficient or water-logged, or it could mean you're cutting the grass too short.
Weeds will also pop up in a healthy lawn, of course. For the most part, this isn't anything to worry about. Almost all lawns have weeds, and they don't do much harm in small numbers. Simply pull up any weeds that detract from the lawn's appearance. If you have a larger weed problem, spray the individual weeds with a low-toxicity herbicide. Don't spray the entire lawn unless you have weeds throughout.
Pest control is similar to weed control. If you have a healthy, thriving lawn, you shouldn't have to worry about it. Bugs will make their home in your lawn, but they won't be able to damage the grass much.
From time to time, however, bugs may destroy some of your grass. You can treat infestations by spraying insecticide or certain bacteria (namely, Bacillus thuringiensis, or Bt). Only use insecticides that kill harmful insects specifically. Ants and spiders prey on lawn pests, so you certainly want to keep them around. Check out this site for more information.
Diseased lawns are usually caused by fungi feeding on the grass plants. Healthy grass stands up to fungus very well, but it develops disease now and then. Fight persistent or widespread fungi with a fungicide, available at any garden center. This site explains how to identify and fight common lawn diseases.
Lawn care is as complex as you want to make it. If you must have your own personal golf course in the backyard, you might devote many hours a week to your yard. If you just want something covering the ground, you could plant native grasses that pretty much take care of themselves. The links in the next section will show you the available options and expand on these basic guidelines for proper maintenance.
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