You can identify heat stress in your lawn pretty easily. Typically heat stress will start in blotches; often times following sidewalks, driveways and other moisture drawing surfaces. Certain types of grass are also more susceptible to dormancy. Eventually, the entire lawn will start turning brown and entering a dormant state- much different than the small patches of dead lawn you might find if you have grubs or dog spots. You can also look back at weather reports. Grass typically needs around 1.5 to 2 inches of water per week, so if rain hasn’t been in the forecast and your irrigation system isn’t up and running there’s a very good chance your lawn is under watered.