Dormant Grass in Warm Weather

Maintaining a golf course in Las Vegas is more difficult than most people realize. Keeping a golf course in top shape requires a keen understanding of grass and how it reacts to the climate it is growing in. Las Vegas has a very unique climate that requires special attention and different grasses than other parts of the country.

If you have ever played golf in Las Vegas during the fall, you will most likely have experienced the overseeding process. This process usually occurs between the end of September and early part of October. It is necessary to overseed in order to keep the golf courses green throughout the winter.

Many golf courses in Las Vegas need to use a more resilient strain of grass during the summer months for it to survive. These grasses are called warm-season grasses and include Bermuda grass, Zoysia grass and Centipede grass. Although these grasses grow well in high heat they do not grow well in cold weather. Warm-season grasses grow best in temperatures that range from 75 F to 95 F. This is the reason for overseeding.

Siena hole 6As the temperature starts to drop, the warm-season grass begins to go dormant. Dormancy has been described as a period of rest or non-growth. This is different than dying; the grass will turn yellow and wait until the temperature heats up enough for it to grow again. One of the ways to tell whether a grass is dormant or dead is by looking at the crown of the grass. If the crown is hard and solid the grass is merely dormant, but if the crown is dry and flakey, the grass is dead. According to www.allaboutlawns.com, “The secret to grass, if there is one, is the fact that all of its growing takes place from what is known as the crown: a part of the stem that is at or near the surface of the ground.” When the golf courses start the overseeding process they need to dry out the grass. They will stop watering the golf course several days prior to the start of overseeding. According to Steve Swanson, Director of Grounds and Golf Course Operations at Red Rock Country Club, “…it is much healthier to let the grass go dormant than overseed.”

When a golf course overseeds they need to thin out the warm-season grass in order for the cool-season grass to find the soil. This, in a sense, will chew up the warm-season grass to expose soil.

Dormant grass is very sensitive and needs to have as little traffic on it as possible. Any damage to the crowns will slow the grass’ return with the coming of the warm temperatures.

When the golf courses overseed, they use a cool-season grass. These grasses thrive in the cool weather and will be green all winter long. These grasses include Kentucky Blue Grass, Tall Fescue and Perennial Rye Grass. Timing is critical during the overseeding process. If the seed is put down too early there is the possibility the seed will be burned by the hot sun. If it is put down too late the grass will have a longer gestation period and won’t take hold as quickly.

Due to the cost associated with overseeding, many golf courses will only overseed certain parts of the course. Typically they will overseed the tees, fairways and greens. This will leave only the rough to go dormant. This creates green grass outlined by a yellow perimeter of rough. Many people not familiar with this condition assume the course is in poor condition when the opposite is actually the case.

The rough is left this way on purpose for several reasons. Many people like the contrast between the green and yellow. This contrast will frame the golf hole better and give the golfer a more defined target to shoot at. Also, during the winter the rough will be thinner and easier to hit out of. This will increase the pace of play on the golf course for all golfers.

By not overseeding the roughs the golf course will get into better condition quicker. Many golf courses require cart paths only during the overseeding process. The less overseeding that takes place will allow the golfers to use the 90-degree rule sooner.

In addition, the dormant grass will require less water than active growing grass. This helps to conserve water in the dry Las Vegas desert where water shortage is a constant factor. This is better for everyone in the long run.

As the warm temperatures start to come back, the cool-season grasses will begin to die out and will be replaced by the warm-season grasses waking up and starting to grow again. Then the process will start all over again in the fall.