Drought Stress and Damage Alert:
The July weather has hit lawns hard: Many lawns in the Denver area are showing heavy drought stress and insect damage.
One of the first signs to look for beyond the brown spots in any stressed lawn is seeing if walking across it leaves easy to see footprints, or does the grass quickly rebound after being stepped on? A drought stressed lawn does not rebound, and foot impressions can be seen for a much longer time.
Water starved grass loses its luster as it gradually changes color from the nice dark green shade we are all used to seeing, to a dull blue-green or even grayish-green tint. This is the first sign of a lawn going dormant from lack of water. As conditions worsen, the color may continue to decline to a tan or straw color.
Keep in mind different lawns react differently to drought stress. A healthy lawn with deep roots will handle hot dry weather much better than a lawn that is not as well established or that has a shallow root system.
All lawns benefit from receiving about an inch and a half of water per week. Just as important as the amount is how the watering is done.
Watering less often and more deeply helps grass establish deeper roots. Watering daily or for only short periods of time keeps roots near the surface and the whole of the lawn is then weaker and less able to handle the hot dry weather.
Checking water coverage is also important. Seeing more green around sprinkler heads is a sure sign the application of water is not even. The same holds true for areas between sprinkler heads. In some cases the heads hit far away and close but not as well in the middle. Never assume that just because all the heads pop up the lawn is getting evenly watered.
Allow your lawn to grow. Lawns with a grass blade between 2.5” to 3” are going to be much healthier than a shorter lawn. Keeping the mower blade sharp is another important lawn mowing practice. Although lawn growth will naturally slow during long spans of high heat and little natural moisture, taller blades tend to stimulate a better root system, and shade the soil to cut back on evaporation.
Ascochyta and insects:
Several insects like dry lawns, including chinch bugs, sod web worm, and billbugs. At the same time the drought related fungus Ascochyta often blights the tips of the grass. If you suspect the problem is not just lack of water, checking the lawn for insects and diseases and then properly treating for them can be the difference between the lawn recovering or not.
Keeping a lawn growing requires proper nutrition, just like it does for any living thing. To this end, a good blend of fertilizer will help keep the lawn healthy and green. However, applying too much during high heat could be detrimental to the lawn. This is especially true since lawn growth diminishes during hot spans.
Many over the counter fertilizers are not really good for a lawn during the heat of summer. Having a blend made for higher summer temperatures is much better for a lawn than a blend that promotes fast growth.