Three MIT students invented plantable pencils. Now, over 50 million have been sold.

Picture this: After using your pencil down to the nub, you plant it and watch flowers bloom. Three MIT students dreamed up the idea of plantable pencils during a design course in 2012 and decided to make the company a reality. Now, SproutWorld, which has its American office in Boston, has sold over 50 million sustainable pencils.