It's Arbor Day, Charlie Brown 1976 ( 6.603)

To celebrate Arbor Day, the gang decide to do a great gardening project for Charlie Brown. Unfortunately, Charlie Brown learns that they did it in his baseball diamond, turning it in to a lush garden. With no alternative, he is forced to play against Peppermint Patty's team in that field. However, the bizarre setting seems to be working to his advantage.