Germination depends on adequate moisture and temperature above 50. As Smallaxe pointed out, not much else matters.
If this is a shade problem...seed might germinate...but the grass won't last long. Sod is poor in the shade, (although it might look good at first.) Shade-thinned areas should be planted with one of the well-known shade-adapted ground cover plants: myrtle, ivy, pachysandra, lamium...and more.
One additional potential problem is that there is some chemical in the fill sand that was brought in. Take a sample of the fill and try to grow some of your seed inside on your windowsill. Compare to good soil. And while you are doing that--try a different type of seed. Its possible the original seed was stored too long or under too hot conditions. Under ideal conditions, perennial rye should be a quarter-inch tall after 96 hours.
Show the customer the results. Ask to see his water bill. Never believe when a customer tells you how much he watered.
Hope this helps. We are trying. Grass seed isn't easy. Sub will blame it on the homeowner. Your arguments will fall on deaf ears. Ms Experience is a great teacher, but she is mean. Sod is a good choice. And get a new sub.
Last edited by RigglePLC; 10-26-2012 at 08:52 PM.