the plants start flowering when you cut the lighting down from 18 hours light and 6 hours darkness veggin mode ,down to 12 hours light to 12 hour darkness, then start the stretch where plant stretches and goes in to flowering ,,,mac,
hi hi there i didnt know you were growing in green house mate ..so my answer would have been the same as @puffnstuff1960 has stated in his post ,,,,mac,