We’re just coming through our first heat wave of the season and many lawns are showing signs of stress. If you’re wondering why your lawn is brown, yellowish or overall not up to par, there are a few factors – in addition to heat - that may have your lawn looking less than lush.

This week brought our first real heat wave of the season and reminds us we need to know how lawns react to heat stress. Most Colorado lawns are bluegrass and they have their own coping mechanism to deal with temps in the 90s. They shut down, start to go dormant and may even look dead. Because of the way the lawn looks, people assume it needs more water – but that isn’t necessarily so.

Push a screwdriver into the soil and if the soil is hard, you need to water. Avoid over-watering as that can cause even more disease problems. Avoid watering longer than about 20 minutes as the lawn can no longer soak in the water and it runs off. Whether you use a sprinkler system or a hose, apply water for short intervals, let it soak in and then water again later.

Many lawns have been damaged from more than this week’s 90-degree days – going all the way back to last fall when there was little or no moisture. If you didn’t water between October and spring, your lawn may be suffering now and more susceptible to diseases.

A disease problem seen during hot, dry periods is a fungus called Ascochyta. Patches of lawn quickly turn to a straw color - even overnight - and appear to be dead. Frequent mowing and dull mower blades can make it worse.

Fungicides are usually less helpful than how you care for your lawn. Avoid mowing the lawn when it’s wet, sharpen mower blades, raise the height on the mower and mow less frequently. Also critical is maintaining consistent soil moisture. Grass usually recovers within a couple of weeks because the roots are not affected by the fungus.

Information courtesy Associated Landscape Contractors of Colorado, sponsors of the 9News Water Wise Garden and the 9News Kitchen Garden.