Static Grass mix...

... in the americaN-Norm

One part of each Heki "Sommerwiese" (3360), "Wildgras" (3367) and "Winterboden" (3363).

If you use turf (Woodland Scenic) its either "Aride":
2 parts  T50 (Mischung Erdboden / earth blend) + 2 parts T43 (fein beige / yellow grass) + 1 part T44 (fein Herbst / burnt grass).

or "Humid":
2 parts T44 (fein Herbst / burnt grass) + 1 part T45 (fein Sommer / green grass) + 2 parts T50 (Mischung Erdboden/earth blend).