Yes, grass paint can stain concrete, but that stain can easily be removed with some dish soap, water, and a wire brush. Keep in mind that it is best to try and scrub away the grass paint from the concrete as soon as possible in order to prevent it from drying. While grass paint can still be removed once the paint is dried, it is a lot easier if it’s still wet. Another way to prevent the grass paint from sticking to the concrete is to wet the concrete before you begin painting the lawn. This is what we do on all of our jobs.
To learn how to paint lawns like a pro, check out this article.