As for the scientific reason why plants DO grow at night, here you go:

[align=left]During the daytime, plants produce energy in the form of ATP and NADPH (light reactions)...during the night, these energy forms go to the dark reactions (Calvin Cycle) to fuel the production of organic molecules from CO2 collected during the day...some of these organic molecules will be stored (starch) and some will be used for plant structural growth (cellulose), and some for other organic molecules (lipids, proteins, etc).[/align]

[align=left]GTD[/align]