Nature speaks to the core of our being. Unless you happen to live in the woods or on a beach or a farm, there is a bit of effort involved in finding actual lush nature in the immediacy of your life. Public parks and botanical gardens do count as nature, but the best you can do for yourself is to immerse from time to time in something of nature a bit more wild, a bit less shaped by humans… Get quiet & learn to be. Its pretty simple. And as Thoreau says, best to do it now then to wait till you can reflect on your life to see that you missed the point!