Kaios wrote:There's no way you could grass those tiles that are at the edge of the water, when you highlight that tile or use a grid overlay you would see that half of it will be the land terrain and the other half of the tile water terrain. You would be unable to modify this tile in any way.
Try it yourself.
that proves only that he didn't sow the grass himself. but he's saying that not only did the grass grow by itself over the natural soil (which you explained), but it also grew over the shallow water tiles. Amanda clearly showed this isn't the case as there's natural soil reaching up to the deep water, which we definitely know doesn't spread.