russrahlanswered grow question 4 years ago You can apply the screen any time really. Best to try and fill about 50-70% before flipping to 12/12 if a photo period strain. Put it about 10”-12” above your pot and just tuck whatever grows over the screen back down wherever you can untill about the 3 week mark into flowering you can do a final defoliation then let them grow up towards the light. Hope this helps, cheers 💨