Is this sufficient darkness for swim's flowering plant!?

So, about a week ago I noticed very tiny pistils popping out on my plant! It's a stealth grow so I can't just leave them outdoors during the night, plus there's an effin lightpost outside that hits right on my window! I decided to put the plant inside a cardboard box right next to my window after the sun sets until I wake up at 9pm, but in order to make it as dark as possible I'm closing it completly and only leave a thin line for airflow where the box opens. It spends the entire day outdoors but is this going to "asphyxiate" swims' plant at night? and is this enough darkness? or a I going to far?

http://i743.photobucket.com/albums/x...0/IMG_2041.jpg

http://i743.photobucket.com/albums/x...0/IMG_2036.jpg