Is your lawn a green velvet carpet that's cool on your feet and lovely to look at? Or, is it splotchy with brownish spots and weeds? July brings folks into the office in droves with lawn problems.
The first step in improving the health and look of your grass is to check the sprinklers. Is the water being distributed evenly? What looks like perfect coverage to the eye is often not. Some areas may be getting less water than they need, while others are getting too much. Even a well-designed sprinkler system needs regular checkups and corrections. Clean sprinklerheads to unclog them and replace worn or leaking heads. Straighten them or raise them if below the level of the lawn.
Often the problem is poor overlapping spray patterns. If this is the case, you need to "can" your lawn. This will determine how long and how often to water your lawn. Distribute randomly around your lawn, 10 or more straight-sided cups or cans like coffee mugs or soup cans, at least 4 to 6 inches deep, all with the same diameter. Put some on green spots and some on brown spots of the lawn. Check each station of your sprinkler system.
Run the sprinklers for 15 minutes on a calm day. Observe the amount of water in the cans. There should be the same amount of water in each container. If not, your coverage is uneven, and this may explain the brown spots. Lack of water will stress your turf. Stressed turf can't resist insects and diseases and can't compete with weeds. You may need to adjust sprinkler heads to fix the problem. If the water levels vary by more than 50 percent - one can contains 3/4 of an inch and another 1/4 of an inch - you may need major repairs.
In general, during July, you need to apply almost 2 inches of water per week. Based on the "can" test, you can calculate how many minutes per week you need to run your irrigation system. If your lawn receives 1/4 inch of water in 15 minutes, you must run your sprinkler system, whether automatic or manual, for a total of 2 hours per week.
Are you watering your lawn enough and efficiently?
Cooperative Extension has a new Web site that tells how much water you need to apply on your watering day when watering twice a week, based on the type of sprinklers you have and the weather conditions. This is called the "Et" or Evapotranspiration rate. For example, when the temperatures are up in the 90's, a popup sprinkler needs to be run 46 minutes on your two watering days. An impulse head must be run for 114 minutes and a stream spray rotor needs 54 minutes.
It is best to break these up into three or four watering sessions on your watering days, to achieve the best penetration. Needs will vary according to water pressure, nozzle size, coverage, soil type and slope. Check out the web site www.extension.unr.edu. Or call 887-2252 for the "All Seeing, All Knowing Lawn Care Manual."
JoAnne Skelly is the Carson/Storey Extension Educator for the UNR Cooperative Extension.
