In the [2008 movie WALL-E](http://www.imdb.com/title/tt0910970/), we see the WALL-E robot rummaging through some trash early in the movie. It comes across an old refrigerator which it cannot open via normal means, so it cuts it open.

Inside the refrigerator we see a small plant growing. Plants require light, fresh air, and water to grow: none of which are available inside of a closed refrigerator sealed so tight it had to be cut open.

How did the plant grow inside of a closed refrigerator?