Gardening
Time now to begin mowing the lawn
Keith Hansen Smith County Horticulturist

Ladies and gentlemen, start your engines.

Yes, it's time to bring mowers and spreaders out of winter storage and pay attention to the lawn. No doubt the most common landscape feature of any yard, big or small, is the lawn. It forms the foundation of the entire yard, and performs many valuable functions.

Lawns eliminate soil erosion, reduce runoff and pollution, lower surface temperatures, muffle noise, reduce glare, and filter harmful pollutants from the air.

Lawn grasses, like other living plants, consume carbon dioxide and release oxygen. Plus, lawns provide inexpensive recreational areas.

So, it's no wonder that we put so much effort into this sward of green. But, the main goal of most folks is simply to have a pretty, green lawn. Although maintaining a quality lawn is a year-round task, there are three simple points that, if followed, will result in a thick, weed-resistant, healthy lawn. These three keys are mowing, fertilizing and watering.

Mowing: Mowing tops the list of factors that can make or break a good lawn. It's more

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height, place your mower on the driveway and measure to the bottom of the deck and adjust the height as indicated in the table.

Mowing frequency depends on the growth rate of the grass.

The rule of thumb is to remove no more than 1/3 of the blade of grass. So, if you keep your mower set at 2 inches, cut the grass when it reaches 3 inches tall. This reduces stress on the grass and also lets you mulch the clippings right back into the lawn instead of bagging the clippings.

Obviously, the faster the grass is going, the more frequently you will need to mow to prevent stress from removing excess foliage.

One other key to mowing - keep that mower blade sharpened! Pick up sticks and stones that can quickly dull the blade which results in torn grass instead of cleanly cut grass.

Fertilization: Turf grasses differ in their requirements for plant nutrients, especially nitrogen. Typically, centipede needs the least amount of nitrogen, while bermudagrass requires the most. Grass clippings return valuable nutrients back to lawn as they decompose, so the total fertilizer requirement can be reduced if clippings are left on the lawn. (And clippings do not add to thatch, as some believe, so do your lawn and the landfills a favor and not bag your grass clippings).

A soil test is an invaluable tool for determining your lawn's nutrient needs.

Most soils in our area are low in nitrogen and potassium (represented by the first and third numbers on a bag of fertilizer). Phosphorus (the middle number on the bag) typically is high, especially in lawns that have a history of being fertilized with a complete fertilizer.

There are many formulations of fertilizer on the market, and no one product is best. In the absence of a soil test, a general recommendation would be to use a product where the three numbers are in a 3-1-2 ratio (like 15-5-10, 21-7-14, 18-6- 12), or a 4-1-2 ratio (such as 16- 4-12). Generally, keep the first number (nitrogen) and the last number (potassium) close, and the middle number (phosphorus) low.

For slow, even growth, use a fertilizer containing nitrogen in a slow-release form, such as sulphur-coated urea, ureaformaldehyde, or plastic-coated urea (eg. polyon). This is especially important for lawns on sandy soil. Organic fertilizers provide sources of slow release nutrients and also help build up the soil.

How much fertilizer do you put out? First, you must know the area or square feet of the lawn. Multiply the length times width for each section of lawn, then add them together to get the total square feet. Write this down and keep it where you can refer to it in the future.

Many lawn fertilizers will indicate how much area the product will cover. A handy fertilization guide is included in Extension's 'Don't Bag It Lawn Care' pamphlet available for free in every county Extension office.

A soil test will also give you the pH of the soil which indicates the acidity the soil.

By knowing the actual pH, you will know whether or not you need to lime the soil, and how much to use. Centipede can tolerate a lower pH and usually doesn't need liming.

When to fertilizer is always a big question. Turfgrass specialists with the Texas Cooperative Extension recommend the following dates:

Common bermuda - April 15, June 1, July 15 and Sept. 1.

Centipede - May 15 and Sept. 1.

St. Augustine - April 15 and Sept. 1 (and June 1 if grass is not growing well).

Zoysia - May 1, June 1 and Sept. 1.

Notice that the first application of fertilizer in the spring is fairly late. The reason for this is that grasses develop a stronger root system if allowed to green up without being forced into vigorous top growth by early nitrogen fertilization.

Watering: Even though grass may be brown, it still needs to be watered periodically during the winter - not very often - but it needs to be kept out of drought stress.

During the driest part of summer when grass is rapidly growing and evaporation rates are high, lawns need about 1 inch of water every week, whether through rainfall or irrigation.

Check your sprinklers for their output by placing a few cans around the sprinkler heads and measure the accumulation over a 15 or 30 minute period.

This will give you an idea of how long you need to run your sprinklers to get the proper amount of water. It is best to supply the total amount of water required in one or two applications so the soil will be wet about 5 to 6 inches deep.

Frequent, shallow watering promotes a shallow root system which is more subject to stress and grub damage.

Water in early morning. Less water is lost through evaporation in the morning, and the grass dries quickly, resulting in fewer disease problems.

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Keith Hansen is Smith County Horticulturist with Texas Cooperative Extension. His web page is http://EastTexasGardening.ta mu.edu