Lawns sometimes get a bad environmental rap for the amount of water, fertilizer and pesticides that are applied to keep them green. However, lawns do provide important qualities. They 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. Although maintaining a quality lawn is a year round task, there are 3 simple points that, if followed, will result in a thick, weed-resistant, healthy lawn. These three keys are frequent mowing, proper fertilizing and timely watering.
MOWING. Mowing tops the list of factors that can make or break a good lawn. It’s more than just cranking up the old mower whenever you get the urge, or when grass gets knee-high. Improper mowing is responsible for the deterioration of many lawns. Mowing too close and too infrequently causes scalping and shallow rooting, which lowers the turf’s resistance to drought, diseases, and weed invasion.
There are two interrelated points that go into mowing: 1) mowing at the proper height for your type of grass, and 2) the proper frequency - both go a long way to develop and maintain a top-notch lawn. Here are the recommended mowing heights (in inches) for different grasses:
Common Bermudagrass: 1 – 2.5; Hybrid Bermudagrass: 0.75 – 1.5; St. Augustine: (in sun) 2 – 3; (in shade) 3 – 4; Zoysia: 1 – 2; Centipede: 1.5 – 2.
To set the lawnmower’s cutting height, place your mower on the driveway and measure to the bottom of the deck and adjust the height as indicated above.
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. For example, 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. This might mean mowing every 4 or 5 days in the summer.
One other key to mowing – keep that mower blade sharpened! Pick up sticks and stones that can quickly dull the blade, resulting in torn grass instead of cleanly cut grass.
FERTILIZATION. Turf grasses differ in their requirements for plant nutrients, especially nitrogen. Centipede needs the least amount of nitrogen, while bermudagrass requires the most. Grass clippings return valuable nutrients back to the lawn as they decompose, so the total fertilizer requirement can be reduced if clippings are returned rather than bagged.
A soil test (use Urban Submittal Form) 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 or a 4-1-2 ratio. 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. 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? Determine the area or square feet of the lawn. Multiply the length X 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.
A soil test will also give the soil pH which indicates the acidity of the soil.
By knowing the actual pH, you will know whether or not you need to apply lime, 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. The first application of fertilizer in the spring should only be after the grass has begun growing, which often is not until mid to late April. 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. During the winter, even though it may be brown, grass still needs to be watered periodically – not very often – but it needs to be kept out of drought stress. Dry lawns during a cold winter like we had are more prone to injury.
Providing adequate supplemental irrigation for spring green up is very important. If rainfall does not occur, then approximately 1.0 inch of supplemental irrigation water should be added to the lawn each week. While it is important to make sure adequate soil moisture is available for spring transition, it is also important to make sure the landscape is not over watered. Excess irrigation will create shallow rooted plants going into the hot, dry summer months, and it can also encourage disease problems such as gray leaf spot in St. Augustinegrass.
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.
Water in early morning. Less water is lost through evaporation in the morning, and the grass dries quickly, resulting in fewer disease problems.