Why: Not enough water is most likely.
Solution: Increase the watering periods. Every 3 hours for the first week. Just don’t let the area dry out.
OR. The ground is too hard. This can happen even after the Hydromulch has been sprayed. Walk carefully to the area and break up the ground with a pick. Then water it again. Things should start to grow.
Why: Temperature may too cool. Too little or too much water.
Solution: Be patient. Increase the watering times. If too much water and its boggy, then cut down on the water.