Here’s some news from my Sesame Street contact:
Our entire 40th season curriculum is titled "My World is Green and Growing" and is focused on connecting preschoolers with the wonder of nature. 15 of the 26 episodes for the upcoming season have an "Enviroment and Science" theme. Much of this will include growing plants!
Sesame Street normally airs on MPT M-F at 9:30 AM. Check you local PBS listings.