The Dirt on Grass

Summer is fast waning, and along with it so is the grass around many Carson City homes. Round bare spots, long bare spots along sidewalks, patches of dull yellowed spikes abound.

What's the problem?

"Well, you've either got bugs or patch or thatch," suggested David Ruf of Greenhouse Garden Center on Curry Street. "Grab a tuft of it and pull it up. If it comes up clean, and there's dirt underneath, it's bugs. If not, it's probably a fungus. Or if the thatch - the layer of cut grass, roots and debris - is more than three-quarters of an inch thick, it's blocking water and sun and killing the grass.

"Use a bug poison for the bugs, a fungicide for the fungus and a heavy rake to get rid of the thatch. We sell special heavy rakes just for that problem. You rake up the dead thatch and reseed or add sod."

But there's a lot more to grass problems.

Hot weather can cause a variety of problems for lawns, including heat stress, drought stress, crabgrass explosions and patch disease.

Crescent-shaped or circular patches of dead grass, often with clumps of green grass inside (called frogeye), are symptoms of patch diseases.

Lawns with advanced disease s may show irregular dead areas and streaks. Lawns with various stress problems typically develop patch diseases.

Grubs or other insects may kill large areas of a lawn, with the worst damage showing up in late summer. In affected areas, the sod can be rolled back to reveal the bugs.

Extensive bird predation are signs of grubs or sod webworms, which live in the sod and feed on the leaves and stems at night. The worms chew grass blades off just above the thatch line, pull the blades into their silken tunnels, and eat them.

Circular or irregular brown patches of close-clipped grass are often a sign webworms are abundant. Numerous small holes (the diameter of a finger) are often found in the dead patches. These holes are made by birds seeking the large sod webworms.

When large brown areas occur in sunny areas, look for chinch bugs in circles of grass that have turned yellow around dead patches.

Punch the affected spots and adjacent green area with a knife blade or screwdriver. If the brown spot is hard and the green area soft, a lack of moisture in the brown spot may be the reason.

Another cause of lawn problems is dull mowers or mowers improperly adjusted crimping the grass, instead of cutting it. The dead leaf tips cause a general browning. Mowers in poor condition may cause grass to fray, and the grass will show a white cast with brown tips.

Keep the lawn clipped at the proper height. Too short a cut will weaken the grass and make it susceptible to a disease, and too tall a cut will hold sprinkler moisture so the grass fails to dry rapidly.

Female dogs' urine may cause green or brown spots on a lawn. The larger a dog, the drier the soil; and the higher the temperature, the more damage will be done. In or around the affected spot, the grass not killed will turn green because of nitrogen in the urine.

If the thatch layer builds up to a certain level, it compresses and becomes hydrophobic, meaning it blocks water movement. It can also prevent the ability of fertilizers and pesticides to reach intended targets.

Contact Sam Bauman at sbauman@nevadaappeal.com or 881-1236.