Answer: There are two common causes for newly installed sod to turn yellow; one is lack of sufficient moisture and the other is a sod webworm infestation. It isn't likely that grubs have already invaded your new lawn, so I wonder if your watering techniques aren't quite delivering the necessary moisture for the roots of your new sod to grow into your native soil.
The most important responsibility you have is to keep your sod moist. During the first 2 weeks, after installation you should be watering 1-2 times per day (30 minutes per sprinkler location), or more often if needed. Your sod must be constantly moist for those first 2 weeks. Let moist sod be the guide ? if you have some sod yellowing in the first few days, you will need to water those areas longer, and more often. But make sure it's not yellow because it's drowning!
To achieve the level of water coverage necessary you may have to purchase multiple sprinklers and hoses, and still have to move them around every day to ensure total coverage. After those first two weeks, watering 2-3 times per week (30-40 minutes per sprinkler) should be sufficient. Two weeks after the sod is laid, it should be ready to mow! Keep your lawn trimmed to a height of 2 ?".
Hope this information helps you determine just why your sod is yellowing and dying.
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