Yes that is a thought process similar too mine.
How many hours are you down to when you chop?
Do you just shave the one hour the whole time or hour every few days?
A 14 week sativa is down to 10 hrs.
A 16 week sativa is down to 10 hrs strain dependent....(Landrace plants to 10-11 only - no lower.....Some equatorial landrace strains don't get reduction at all. Thai and Vietnamese black have problems with light reduction. So does Lambs breath).
Reductions are done weekly - start slowly in 1/2hr increments. Less for landrace, more like 15min a week, starting at week 12
Only Sativa's get the reduction and then only 90% plus cross's or landrace get it....I begin at week 10.
Indica's start at 11/13 and stay there. Period.
Doc
Dark periods do not. understood. But is the reason you wstill decrease bloom times with some strains because what cobnobular said, to make e plant think the season is ending and pack it on as much as you can?
Reducing lights on times do make the plant speed up the finish some....Like I've had a few Sativa's simply not want to finish....drop them to 10hrs and they pick up and finish......The amount of time cut from bloom = not as much as you'll think.
In trials/testing done at times down to 6 hrs you only cut about 7-9 days off the bloom......At 6 hr bloom times. Expect about 75 to 78% of your normal yield.....You can make that better by adding to the lighting intensity and gassing.....I have been able to increase that yield to about 90% at 7-8hrs by increasing lighting intensity by about 30%......New, higher output bulbs and 20% higher reflective hoods....(good luck finding Jupiter 6 &8 hoods - The company folded and he is selling off the stock...I had to practically fight for the 10 hoods I got). I find that 10 hrs seems to be the tipping point for loss of yield.....It starts out low or very little, almost you can't tell unless you weigh everything carefully.......Once you hit 8 hrs your loosing!
It should be noted that this loss in yield was done in straight 6-7-8 hr lights on times - no slow reduction of on times.....I have not gone below 9 hrs in reducing time.....
Doc