Over-watering your outdoor living space is equally as destructive as shallow watering and ends up with similar problems—shallow roots.  Again, surface roots are temperamental and result in an unhealthy lawn.  Additionally, over-watering can cause yellowing in the lawn, which is sometimes confused for a lack of water and results in increased over-watering. 

Another problem caused by over-watering is the deprivation of the soil profile of oxygen, resulting in the death of beneficial organisms.  Commonly this will be marked by several uneven bumps developing in the lawn caused by the exit holes of worms trying to make it to the surface to breathe. 

Fixing the bumps is a timely process, but is possible and involves a regiment of aeration, mulching instead of bagging your grass clippings, and applying a thin layer of fine-grade mulch.  The solution to the problem is to spread out the frequency of your watering.  Never should you need to water every day, even with new sod or seed.  I will address this more later. 

During the hottest months of the year—July and August—I have been able to water some lawns as infrequently as every 7-10 days.  You need to have the right type of soil and a deep root system to do this, but it is very possible. 

The best way to gauge how often you need to water is by testing your soil frequently, once again using a screwdriver or soil probe.  You need to water when the soil is dry down about 25-30% of the root depth.  Let it dry out even more if you are brave, but keep an eye on the color and turgidity of the grass. 

If your grass starts to go darker or lay down, it is on the verge of drought-stress and you need to water.  A good way to test is to walk across your lawn, if you can look back and see deep footprint impressions, you need to water again.  Even with a very shallow root system, do not water more than every other day or you will over-water and suffocate your lawn.

One more note on the frequency of watering.  You may find, from testing, that in order to fill your root system you need about 2” of water for a deep, heavy clay.  Be careful about turning off your clock when it is rainy.  Check the soil and watch the lawns color and turgidity because rainwater is never enough in Utah to fill the soil profile. 

According to www.maps.com, most of the inhabited areas of Utah only receive 8-16” of water a year.  Yes, that’s right, a year!  If you are applying about 2” of water per application, that is somewhere between one and two full months worth of rainwater—in other words, rain is not enough to keep your lawn healthy.