Huzzah. It's amazing how a small suggestion can change the course — and success — of a painting and often that seed comes from a non-artist. I told my partner that I don't like the grass in this painting, and he suggested that I think about time of day. Imagining a night scene, for instance, means the grass can be dark in most places, with streaks of lighter blades going through wherever I imagine the moon to shine.
So I washed Payne's Gray over the grassy field, except for the tips of the grass. Some of the original green was still wet and there's a nice mix into the greens below.