Question
I hope you can help or point me in the right direction. Hello. I live In Colorado Zone 5. I have bluegrass for my lawn. My soil seems to be pretty sandy. For the past 3 years I have had issues with my lawn. During hot periods certain parts of my lawn (by the egde of the driveway and street) turn a grayish/dark color and start to die. Whats really strange is I notice this then get my soaker hose out and water for abot 1/2 hour than within about 2 hours that part of the grass greens up. I have never seen grass green back up that fast. All the lawn care outfits claim its mites doing this, but I have used bayer insect killer and all other kinds and nothing seems to work. Someone claimed it wasn't getting enough water, but I water everythird day 2 times on the 3rd day for 20 minutes. So I water 40 minutes every 3rd day. Can you give me suggestions? Sorry so long.

Answer
Hi Steve, It sounds to me like it's drying out. Areas around concrete that absorb heat would dry first and since it recovers quickly with water, that seems to validate the diagnosis.
Adding clay and/or organic matter to your sandy soil would help it retain water better, but that may be impractical.  I would suggest that you overseed the area with one of the newer heat/drought tolerant bluegrass varieties like Solar Green or Thermal Blue.   This should allow you to go longer between watering.
You may also want to lengthen the watering cycle.  Try running it once for 40 minutes every third day.  The longer the time, the deeper the water goes and the deeper the roots grow.
In very high temps, you may need to go to every other day watering, but I believe with an overseed of the above, you will not see the stress you see now. Jim