Improving a Lawn
Five Common Lawncare Mistakes
Unfortunately, knowledge isn't hereditary. We learn as we go, this is especially true when it comes to lawn care. Every first-time homeowner has to go through the same basic steps to learn how to care for their lawn. Should I set my lawn mower to a specific cutting height? How much water should I use? When is the best time to fertilize my lawn? These are just a few of the numerous questions that arise.
The Lawn Institute offers these suggestions so you can avoid a few of the basic mistakes people make when it comes to proper lawn care.
1. MOWING: An unsharpened lawnmower blade will actually rip or tear the grass rather than provide a clean even cut. The ripping or tearing of the plant tissue can create a breeding ground for disease and other problems. Cutting your lawn too short is another common mistake that can create an environment that encourages weed growth, increases heat stress during dry or hot periods and makes your lawn more susceptible to insects and disease. Recommendation: Always keep your lawnmower blades sharp. At the outset of each growing season, sharpen the blades or have your blades sharpened by a professional. If you live in a warmer climate, where lawn care is a year-round activity, check your lawnmower blades periodically to make sure they're sharp. Set your mower blade to a height that cuts no more than the top third of the grass plant; this will encourage stronger roots. Cutting your lawn too short not only creates an environment for both weeds and disease it causes the lawn to lose moisture much quicker.
2. WATERING: Water is essential to all life . . . too little water and we die, too much and we drown. The same is true of the grass in our lawns. Water makes up 70% to 80% of the weight of our lawn grasses and the clippings alone are nearly 90% water. While most people are concerned about not watering their lawns enough, the fact is, more lawns are damaged or destroyed by over-watering then underwatering.
Recommendation: Use water wisely and practice water conservation. To establish itself, freshly seeded area or newly installed turfgrass sod has very important watering needs. Proper watering immediately after installation will ensure the turf gets established, and it will also have an impact on how well the lawn continues to flourish for years to come. Give your new sod lawn at least 1 inch (2.5 cm) of water within 1/2 hour of installation. Water daily or more often, keeping turf moist until it is firmly rooted (about 2 weeks). Then less frequent and deeper watering should begin.
The amount of water required for an established lawn will be determined by its overall health, beauty and ability to withstand use and drought. One inch a week is the standard water requirement for most lawns; however, this will vary between different turf species and even among cultivars within a specie. There will also be varying water requirements for seasonal changes and still more differences brought about because of different soil types. Some helpful advice, look at your lawn to determine if it needs water. Grass in need of water will have a grey-blue cast to it. Also, foot prints will still be visible after a half-hour or more on a lawn in need of water, while on a well watered lawn foot-prints will completely disappear within minutes.
You can also use a soil probe, such as a screwdriver or large spike to determine how dry your lawn is. If the probe can be pushed into the soil easily, it's probably still moist, but if it takes a lot of pressure to push in, it's time to water.
Remember too, just because your lawn turns brown during extremely dry periods doesn't mean it's dying; grass will go dormant during such periods. Your lawn doesn't have to be green to be healthy. Most grasses can survive 30-60 days of drought without substantial losses.
3. FERTILIZING: A few of the biggest mistakes made when it comes to using fertilizers is not only using the right mixture, but using the right quantity and applying it at the right time of the year. Often times when spring comes around people feel a need to fertilize their lawns in hopes of seeing a green plush lawn as soon as possible. Too much fertilizer, especially with high levels of soluble nitrogen fertilizer, tends to increase thatch problems and leaves lawns more prone to insect and disease. Or, worse yet, you will literally burn your lawn.
Recommendation: The goal of a good fertility program is to produce a reasonable amount of top growth, but not at the expense of root growth or carbohydrate storage. A good root system is the key factor to a healthy lawn.
Nitrogen (N), Phosphorus (P), Potassium (K)
Lawn fertilizers typically contain these three nutrients, although other nutrients may be included in small amounts. The three numbers on the fertilizer bag represent the percentages of N, P, & K-in that order. The back of the fertilizer bag should show the guaranteed analysis. Always follow the recommended application rates suggested by the manufacturer on the bag.
The grass plant needs more nitrogen than any other nutrient. Nitrogen is part of the chlorophyll molecule and helps give the lawn its deep green color. Nitrogen also tends to promote high leaf growth rates at the expense of root growth. Phosphorus is responsible for the energy transfer systems in the plant and is generally required in much smaller amounts than nitrogen or potassium on an established lawn. The exception is for newly established lawns by seeding, sodding, or sprigging, when the need of phosphorus is higher in the new plant. Potassium has a lot to do with good cell wall development and the plant's ability to withstand stress, disease, and insect damage.
Look for slow-release forms of nitrogen. The two basic forms of nitrogen that can be used as a fertilizer are organic and inorganic. The most commonly used inorganic forms of nitrogen in fertilizers are ammonium nitrate and ammonium sulfate. Both are soluble, quickly available forms of nitrogen and both tend to produce a fast increase in leaf growth for a fairly short period of time.
More and more, the slowly soluble or slow-release organic forms of nitrogen are being recommended by turf experts. These include sulfur-coated urea, urea formaldehyde, I.B.D.U., methylene urea, natural organics, and resin-coated urea. These tend to produce a lawn with good color without excessive leaf growth. They are designed to meter-out the nitrogen over a longer period of time. The slow-release forms of nitrogen do not have to be applied as often.
What fertilizer should I use?
Most turf experts recommend that a lawn fertilizer should have at least one-half of its nitrogen in one of the slow-release forms mentioned above. In most cases, both cool season and warm season grasses will do well when a 3-1-2 or 4-1-2 ratio of N-P-K is used on an established lawn. Some analysis numbers that meet these ratios are: 12-4-8, 15-5-10, 16-4-8, 21-7-14 and 20-5-10.
How much fertilizer should I use?
Fertilizer application rates should be as low as possible and still produce a high quality lawn. Over-fertilization weakens your lawn and causes excess leaf growth. As a general rule, if the amount of Nitrogen (N is the first number in the analysis) is between 5 and 12, the application rate should be 8 pounds per 1,000 square feet. If the N number is between 12 and 18, the application rate should be 6 pounds per 1,000 square feet. Any N number over 19 should be applied at a rate of 4 pounds per 1,000 square feet. Always follow the recommended rate stated on the bag by the manufacturer.
When should I fertilize?
The best time to fertilize a lawn is when it is actively growing. For Northern lawns (Cool Season grasses), begin the fertilization program as the grass begins to grow in the spring and reduce applications as the weather gets hotter. When cooler weather returns in the fall, the lawn can again be fertilized. A late fall fertilizer application after the first frost can increase lawn quality the following spring. For Cool-Season grasses, it is usually best to concentrate a larger amount of nitrogen during the early fall growing period and a lesser amount in the spring.
Southern lawns (warm season grasses), flourish during the warmer summer months, and therefore tend to require fertilizing shortly after green-up in the spring and again in the late summer months. For Warm-Season grasses in the southern areas, it is best to concentrate a larger amount of nitrogen during the early-late spring applications and a lesser amount in the fall. The fertilization program should start just after spring green-up and stop about two months before the average frost date in the fall. Frequency of fertilizer applications depends primarily on the amount and form of nitrogen used. The slow-release type fertilizers can adequately feed the lawn from 6 to 10 weeks. If the lawn still looks good and is growing well after 6 to 8 weeks, wait longer for the next application.
IMPORTANT: By leaving your grass clippings on the lawn, you are adding nitrogen almost continually, which can reduce the need for fertilization by as much as 25%. And, leaving the clippings on the lawn (grasscycling) helps the environment by keeping clippings out of our community landfills!
4. DETHATCHING: Thatch is that tightly packed layer of dead and living shoots, stems, and roots that develop between turfgrass and soil surface. As it is, dethatching takes a little time and effort and using the wrong dethatching equipment can make it a Herculean effort when it needn't be. Some dethatching machines have flexible, leaf rake-type tines that are ineffective in removing thatch. Spring tines that attach to a rotary mower blade aren't good for dethatching and can damage your mower. It's important that you use the right equipment if you are going to dethatch. Don't attempt to remove the entire thatch layer in one treatment and do not dethatch when soil is wet; only dethatch your lawn when it is needed rather than on a routine basis.
Recommendation: A little thatch is desirable, since it helps moderate temperature extremes at the soil surface and provides a cushion effect on the surface but too much thatch can present some negative consequences. To determine if your lawn has a thatch problem, remove a small, plug of turf several inches deep. Note the spongy layer of material between the turf and the soil. If this layer is more than 3/4 to 1 inch thick when you compress it, you should consider having your lawn dethatched or begin program which will encourage thatch decomposition. If you need to dethatch your lawn there are garden centers and equipment rental outlets that rent dethatchers. These machines are known as vertical mowers, verticutters, dethatchers or power rakes and they have vertically spinning blades which pull some of the material to the surface as they slice the thatch layer. Mechanical dethatching should be done in either late summer or fall when cool weather prevails. As is the rule when operating any equipment, follow the manufacturers or rental store's operating procedures. The organic material dislodged by the dethatching machine should be removed and composted. It's also important to note that grass clippings do not cause thatch and they are good for your lawn.
5. AERATION: Aerating a lawn is usually recommended when the soil becomes compacted and water and nutrients can't get to the roots of the plant. Lawn aeration equipment will pull "cores or plugs of soil out of the ground, letting air in. These plugs should be 2"-3" in depth. Such a plug should be pulled out of the lawn at about every 3". The plug-removal process is facilitated by watering the lawn the day before, but don't water to the point of muddying the soil. One of the most frequently made mistakes is the lack of sufficient cores or plugs removed from the lawn. If the tines of the aerator are set more than three inches apart, and only one pass is taken on the lawn, the effort may not have been sufficient to solve the problem. Two passes may be required to ensure that air, water and nutrients can get down to the roots.
Take care to mark all sprinkler heads so that they can be avoided with the aerator. This will save on costly repairs to the irrigation system.
Recommendation: Core aeration, a process where plugs of soil and grass are removed at regular intervals, can be done either by renting equipment or hiring a professional. A cool, dry fall day is the perfect time for this beneficial chore. Core aeration reduces compaction in heavy clay soils, permits a more rapid exchange of oxygen and water with grass roots and reduces the thatch layer on lawns. The soil and grass plugs can remain on the lawn since they will gradually decompose and return all their nutrients to the soil. Often times, two passes in the form of a criss-cross pattern are recommended to make sure aeration is sufficient. Leave plugs on the lawn as they will eventually breakdown and return nutrients to the soil.
The type of grass will determine whether to aerify in the fall or in the summer. Lawns composed of cool-season grasses such as Kentucky bluegrass and tall fescue are best aerified in the fall, when there is less heat stress and danger of invasion by weedy annuals. Allow at least four weeks of good growing weather to help the plants recover. Warm-season grasses such as zoysiagrass, centipedegrass, carpetgrass, St. Augustinegrass and bermudagrass, on the other hand, are best aerified in late spring and summer, when they are actively growing. With either type of grass, choose a day when temperatures are mild and soil is moderately moist, which makes the soil easier to penetrate. Avoid aerifying a wet soil, as it is messy and leads to further compaction of the soil as well. If the soil sticks to your shoes or if the core samples you take stick to your probe, you should wait until it dries out some before starting the job.