This way you will be measuring what light would hit the ground. By measuring on a cloudy day, you will not be bothered by light flecks. This procedure ignores light quality differences in the shade, but is close enough for an estimate. Seville 6.0 Jade 5.3 Bitterblue 4.3 Raleigh 4.0 Floratam 2.3 Means of two observations. There's more going on in the shade than reduced light.
Leaves grow long and are damaged by mowers.
There is less breeze and less need for water, but more chance for fungus and caterpillars. The grass grows more slowly and needs less fertilizer. If you are planting sod which was grown in the sun, it may take several weeks for all the old sun leaves to die off, and for the turfgrass plants to acclimate to their new location. As sun leaves begin to die they will be eaten by fungus. Excessive fertilization and watering of new sod make the leaves tender, and a weak fungus such as Pythium can be encouraged to move onto the live turf, destroying it.