[video=youtube;2FmXHhKFA5U]http://www.youtube.com/watch?v=2FmXHhKFA5U[/video]
check it out, this guys brutal with his plants but it works, looks like hes a week or two into flowering on some of those plants, anyways i didn't really answer your question, you should know if they're alright within hours depending how powerful your lights are, a day or two tops.