"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.
Maintaining Your Lawn
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:
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.Periodic Maintenance
In addition to mowing and watering regularly, you'll need to make time for several larger jobs throughout the year.Fertilizing
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.
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.Aerating
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.De-thatching
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
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.Fighting Disease
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.