So can Turtles Eat Grass? Yes! Most land turtles predominantly eat grass and other plants and shrubs within their reach. The water turtles are mainly herbivores and carnivores. However, they progress as herbivores as they become adults. Grass and plants are nutritious and will form a good food source for your Turtle. If you were concerned about feeding your Turtle grass, there is no problem with feeding them hay, grass, and fruits. #CanTurtlesEatGrass #TurtlesFood