Justaseed,
I am not saying that your opinion is without merit, as you seem to have more experience in daylength than I do,but there are some things that just don't add up here to me.
First the trigger for flowering is in decreasing day length.which happens June 21 everywhere in the northern hemisphere There are modifiers such as temp,light intensity, available nutrients,age, etc.
I think the answer to Madja's question would have to do with when you want to induce flowering by decreasing day length. If you have a strain that will have a problem maturing at your lattitude then decreasing day length by having say 24/0 cycle indoors before putting them out will trigger flowering the day you put them and that's a good thing.
In the North we can't put our plants out much earlier than june 21 so increasing the light cycle while indoors up to a point where the natural day length is longer than the artificial day length will result in a longer veg. which will increase yields as long as your strain will finish in time. That means 12/12 untill they are put outside. If you have good light intensity indoors then there shouldn't be a problem otherwise they may be confused
bro Reviewed by bro on . RUNNING LIGHTS TOO LONG? Greetings, i was just wondering out of curiosity if it would be detrimental to a plant if it were exposed to more than 18 hours, upto 24 hours per day. Either state? Thank you. Rating: 5