Interesting result with light cycle change.

[gnslngr]

Thanks guys- all good info, I 've been growing things for years(mostly tropicals-outdoors), but never artificial lights as the light source. I went with 3wks of 24/7 because my light set up is a little less than optimum-but went to 20/4 on a timer when I left 2 weeks ago, and of course, worrying the whole time....2much ,not enough ,damn I hope that.......pretty funny really.Everything I 've read here seems that was a good course of action.Whew.
Reports from the house this AM are most have 4th set of true leaves.But I'll still wonder anyway till I see em again!

 

[N8thaniel]

Here's a popular article around here

""Optimal growth and yields of tomato and sweet pepper were obtained under photoperiods of 14 and 20 hours, respectively. Longer photoperiods did not further improve growth and yields and even decreased growth and yields in some cases. Although long term use of continuous light is detrimental to tomato and pepper plants, vegetative growth and fruit production of both species can be improved by short term use (5 to 7 weeks) of continuous lighting. Compared to shorter photoperiods, continuous light (24-h photoperiod) increased the leaf levels of hexoses in tomato, of sucrose in pepper and of starch in both species. The accumulation of starch and sugar in leaves under continuous light indicate a limitation of tomato and pepper plants to export the photosynthate out of their leaves. Such a limitation would explain the fact that extra light energy provided by continuous lighting did not result into growth and yield gains"
http://www.actahort.org/books/580/580_9.htm

 
 
so does this suggest that 20hrs of light per day is the best for peppers?

 

[DMF]

If you had actually read this 3 1/2 year old thread, you would have found that the best growth occurs between 16 and 18 hours. 
 
In the experimental results you quoted, 14 is noticably better than 20:
 

 
Optimal growth and yields ... were obtained under photoperiods of 14 and 20 hours, respectively.

 

[Big Kahuna]

If you had actually read this 3 1/2 year old thread, you would have found that the best growth occurs between 16 and 18 hours. 
 
In the experimental results you quoted, 14 is noticably better than 20:
 

 
And if you had actually read this thread, you would see that 14hrs it optimal for tomatoes and 20hrs is optimal for peppers.
 
"Optimal growth and yields of tomato and sweet pepper were obtained under photoperiods of 14 and 20 hours, respectively"

 

[DMF]

Actually, if you read this thread - the one that we're both replying to - you will find a concensus that 16-18 hours is optimal, and that moving to 20 hours did not provide enough dark and inhibited growth. 
 
The question is complicated by where the plants are in the growth cycle.

 

[Big Kahuna]

N8thaniel asked specifically what the study suggested, which is that 20hrs is best for yield for sweet peppers. You claimed the study suggested 14 was better than 20, which simply isn't true.

The only consensus in this thread is that both 18hrs and 20hrs are better than 24hrs.

 

[N8thaniel]

yeah unfortunately there is no mention of light intesity (ppfd) or DLI
 
i was confused about the word "respectively"if  14 was better than 20 or as chilinoob and i both understood it that 14 was for tomatoes and 20 for peppers
 
@DMF  where are u getting 16-18hrs? i think u tried to link a thread but it didnt work

 

[DMF]

i was confused about the word "respectively"

Yeah. Apparently I was too.
 

@DMF  where are u getting 16-18hrs? i think u tried to link a thread but it didnt work

Read through the posts before the study is quoted.  Posters that were using a light cycle report 16-18 hours as producing the best results.  (This isn't news; that period has been generally accepted for many years.)  One poster tried moving to 20 hours and the growth slowed.
 
Of course, these are informal statements.  Surely there must be some studies... 
 
 
 
Since I'm not using lights I'm not motivated to go find them...