Cannabis, the effect from increasing photo-period by only 15 or 30 min.

[Dropped Cat]

All at once. Im going to estimate the 14 days before harvest date and change the photoperiod.

Perpetual still, just different rooms, for different cycles. So the lights run independently from the other rooms.

U will never know if u don't try, so why not. lol I have some respected, and experienced growers saying that it is effective, so its not like im going out on a limb risking much.

Seems legit, if it's just a portion of a bigger grow,
really nothing to lose. Also a one hour bump in hours
per day for a couple weeks overlaps flush time too.
Plants won't freak out while all that's going on.

Interesting. On topic and no bullshit.

Good stuff.

 

[Bubbleblower]

If you want to give your plants as much light as possible here is an idea.
Start with 18/6 for example and reduce the light 10 minutes every day untill the flowering starts.

Not recommended for Sativa's though, as it is essential to use 12/12 or possibly even 10/14 light to night ratio to force the onset of flowering.
I didn't know that before this thread started, from now on I'll have different light schedules for indica's and sativa's.


<of topic>

That is not angle of incidence on leaf surface.

No and it is not a helicopter either, it is what it says it is, not what you try to make of it.</of topic>


The increased light-absorption and higher photosynthetic light use efficiency can increase dry weight yield between 10% and 20%.
Actually that is also of topic, but still interesting.

 

[mr.brunch]

13 on 11 off works lovely, and gives the plants nearly an extra week of light over a ten week flower ( 70 hrs). I believe it was on this site I read that significantly more thc is produced on 12 hrs light as opposed to 11

 

[mr.brunch]

Dj's f13
[URL=https://www.icmag.com/ic/picture.php?albumid=54550&pictureid=1273252&thumb=1]View Image[/url]

I think light intensity plays a role. More light = more flowers. You can go from golf balls to pine cones ramping up the light intensity.

I agree. I was Always taught keep the light as enclosed as you can , and paint it all white , bounce that light about... I go for 400w for 0.5 sq.m all enclosed

 

[Riddleme]

Well I thought I would share this with ya even though there are some that feel it's not possible to bring out Sat genetics in Hybrids with light timing

1st pic is a Mango (KC Brains) that I grew in 2011, back then I was experimenting with increased light timing from 12:30/13:30 to 13/11. Note that the leaves ALL have an Indica look to em

2nd pic is my current Mango now in week 5 of flower. Light timing is 10:30/13:30. You can see that the lower leaves are all fat and Indica looking as they were made in Veg under 18/6 (was before I started playing with Gaslight veg) (which I love by the way) and all the new leaves are skinny Sat looking leaves

 

[Riddleme]

Also brought out the early amber gene which is a Sat thing as well, showing amber trics in week 5 (yeah, I know most are unaware of the early amber thing)

1st pic one of the skinny leaves

2nd pic close up of the bud

 

[mojave green]

I agree. I was Always taught keep the light as enclosed as you can , and paint it all white , bounce that light about... I go for 400w for 0.5 sq.m all enclosed

bounce that shit!

 

[oldhaole]

The effects from increased or decreased light timings do not bring out Sativa or Indica traits.

How do I know this? Simple. I live it.

Welcome to Hawaii. Every year Mother Nature herself messes with our light. Our longest day is 13 hrs 20 min. Shortest is 10 hrs 50 min.

I grow, and have been growing Skunkdog clones for many years. You get no variations in leaf width over this gradual photoperiod change. Summer to Winter, they look the same.

Where the change comes is in yield and the number of days to "finish". All the clones start in 24 hr light. Outside in the day, under lights at night.

A Skunkdog clone under Summer sun takes 90 days to finish and will yield up to a lb. The same clone under Winter sun will finish in less than 60 days and yield two ozs. Seriously. Eight times more.

At 13 hrs 20 minutes I can tell, just from looking, the plant wants to bolt. Anymore daylight, it would. But since we just touch that, then back off, she finishes as expected.

Should you wish to mimic our light cycle I would increase the light a minute or two a day, not all at once. Should you overshoot, your plants will bolt, your trip ruined.

 

[Beta Test Team]

Very well stated, and agreed. (One of the two of us lived on Big Island for a few years.)

Thanks for bringing some clarity to the issue (and sanity).

What we see from 13 hour photoperiod is an extra week or two of flowering and so-called 'foxtailing,' the longer the photoperoid the worse it becomes. Between 12 and 13 hours seems to be the sweet spot in all our testing with various genotypes (granted, no landraces). Greater photoperiod (which means greater DLI) always give us better yield and quality.

Your point about yield reduction is mostly caused by reduction in DLI (and also reduction in PPFD).

 

[Riddleme]

Comparing outdoors to indoors,,,,, nice

Only in my indoor garden, I control all the variables and the ONLY difference is the light timing and I see the changes in ALL the plants, plants that I have grown for many years

it is what it is, but others will try it and see for themselves while some simply disbelieve or argue without cause

 

[DooDahMan]

The effects from increased or decreased light timings do not bring out Sativa or Indica traits.

Clones have less or no options, unlike F2's that have a whole range to choose from.

Very well stated anyway , the 60 vs 90 days is especially interesting. Mahalo.

 

[oldhaole]

Whoa, whoa whoa....

I'm using a single strain clone as an example, for a reason. There are other clones I run, that do the same over the course of the year, just not to the extreme that Skunkdog.

Once you get into the seed realm, I doubt, no two f2 seeds are exacty identical geneticly. That whole range of options you mention? There is no way to tell if any given trait is a product of envionment (ie light) or if that trait was geneticly preprogramed in thru breeding. There is a reason we get a pack of seeds and Pheno-hunt isn't it?

The clones came from somewhere. They were f2's once. I think. Long ago.

 

[Miraculous Meds]

The effects from increased or decreased light timings do not bring out Sativa or Indica traits.

How do I know this? Simple. I live it.

Welcome to Hawaii. Every year Mother Nature herself messes with our light. Our longest day is 13 hrs 20 min. Shortest is 10 hrs 50 min.

I grow, and have been growing Skunkdog clones for many years. You get no variations in leaf width over this gradual photoperiod change. Summer to Winter, they look the same.

Where the change comes is in yield and the number of days to "finish". All the clones start in 24 hr light. Outside in the day, under lights at night.

A Skunkdog clone under Summer sun takes 90 days to finish and will yield up to a lb. The same clone under Winter sun will finish in less than 60 days and yield two ozs. Seriously. Eight times more.

At 13 hrs 20 minutes I can tell, just from looking, the plant wants to bolt. Anymore daylight, it would. But since we just touch that, then back off, she finishes as expected.

Should you wish to mimic our light cycle I would increase the light a minute or two a day, not all at once. Should you overshoot, your plants will bolt, your trip ruined.

Have u grown that cut anywhere else besides Hawaii?

I have cuts that will flower under 15/9, so maybe ur genetics have acclimated to that area.

Ur saying that ur plant wants to revert back during about 14 hours of light?

I don't know that u can compare changes in photoperiod when u live in a area that already influences ur strain.

Also im not sure that physical appearance will be changed or cannabinoid profile, or both.

I do know that a strain ive been running for 10 years turns 30% purple under 11/13 instead of the 12/12 that I have ran that whole time with the same strain.

 

[Beta Test Team]

There are two main issues the deniers in this thread are ignoring:

a. Photoperiod in terms of flowering response (i.e. phytochrome reactions)
b. Photoperiod in terms of DLI (total photons per day)

Both are affected by photoperiod, but only one has a great affect on morphology in terms of this thread, and that's DLI. The DLI issue is what makes most of the visual and chemical difference (it takes a lot of energy for plants to make cannabinoids), and no, it doesn't make a 'indica' into a 'sativa' in any way whatsoever.

Really, this is a critical point I've made so many times, yet the deniers still ignore it...

When you change the photoperiod you're changing the hours per day AND the photons per day. Not one or the other. And these are two separate issues in terms of how they effect plants.

Stop trying to discredit oldhaole, can't you deniers just accept you're wrong? I even posted data showing what happens to some cannabinoids from less and greater than 12 hour photoperiod. And all you deniers have posted is some random and non-cited claims from DJ Short about breeding.

P.S. Miraculous Meds: you should consider typing "you," not "u." The way you write makes me wonder why anyone would take what you write seriously. You're not texting to us on this forum.

 

[Miraculous Meds]

There are two main issues the deniers in this thread are ignoring:

a. Photoperiod in terms of flowering response (i.e. phytochrome reactions)
b. Photoperiod in terms of DLI (total photons per day)

Both are affected by photoperiod, but only one has a great affect on morphology in terms of this thread, and that's DLI. The DLI issue is what makes most of the visual and chemical difference (it takes a lot of energy for plants to make cannabinoids), and no, it doesn't make a 'indica' into a 'sativa' in any way whatsoever.

Really, this is a critical point I've made so many times, yet the deniers still ignore it...

When you change the photoperiod you're changing the hours per day AND the photons per day. Not one or the other. And these are two separate issues in terms of how they effect plants.

Stop trying to discredit oldhaole, can't you deniers just accept you're wrong? I even posted data showing what happens to some cannabinoids from less and greater than 12 hour photoperiod. And all you deniers have posted is some random and non-cited claims from DJ Short about breeding.

P.S. Miraculous Meds: you should consider typing "you," not "u." The way you write makes me wonder why anyone would take what you write seriously. You're not texting to us on this forum.

Im not trying to discredit oldhaole. I respect his opinion. I am just offering mine. Why are u trying to discredit me for saving time writing? We aren't on a science forum sir. It seems that I keep an open mind to what can be, while u are locked into one way of thinking.

U say dli or less photons per day can influence cannabinoids and physical appearance. Hmmm.... isn't that a change then when reducing flower light hours? Less flower light hours equals less photons per day equals physical and cannabinoid changes then, per your words. It seems like that would confirm the changes we are talking about, or am I misunderstanding it.

To be clear im not here to argue with u, I am just trying to learn how this can help me be a better grower, and how I can relate this to the plant to make it better.

Im sorry if I hurt ur feelings earlier in the thread, u just made an assumption of what dj wrote that is incorrect is all.

 

[Beta Test Team]

You're misunderstanding it.

Every change in morphology or cannabinoid profile isn't necessarily a phenotypic change (see "phenotypic plasticity"). Many posters in this thread seem to think every little change is due to phenotype changes or expressions, and that's not necessarily the case.

Less photons per day = less cannabinoids, generally, and lower yields; granted, too many photons per day can be worse than too few photons per day.

This site may not seem like a science forum to you, but to many others it is, at least outside of those forums where people just talk about whatever. To me, using "u" just makes people look like they don't care enough to type two more letters. I for one have a hard time taking anyone who uses text stye writing seriously.

What DJ wrote is incorrect in terms of this thread.

 

[Miraculous Meds]

You're misunderstanding it.

Every change in morphology or cannabinoid profile isn't necessarily a phenotypic change. Many posters in this thread seem to think every little change is due to phenotype changes or expressions, and that's not necessarily the case..

I do think that a physical change is due to the phenotype being altered or just expressing differently .

If not, what else is it?

 

[Beta Test Team]

Here's a worthwhile study to check out:

Climate change, adaptation, and phenotypic plasticity: the problem and the evidence
http://onlinelibrary.wiley.com/doi/10.1111/eva.12137/full


Abstract

Many studies have recorded phenotypic changes in natural populations and attributed them to climate change. However, controversy and uncertainty has arisen around three levels of inference in such studies. First, it has proven difficult to conclusively distinguish whether phenotypic changes are genetically based or the result of phenotypic plasticity. Second, whether or not the change is adaptive is usually assumed rather than tested. Third, inferences that climate change is the specific causal agent have rarely involved the testing – and exclusion – of other potential drivers. We here review the various ways in which the above inferences have been attempted, and evaluate the strength of support that each approach can provide. This methodological assessment sets the stage for 11 accompanying review articles that attempt comprehensive syntheses of what is currently known – and not known – about responses to climate change in a variety of taxa and in theory. Summarizing and relying on the results of these reviews, we arrive at the conclusion that evidence for genetic adaptation to climate change has been found in some systems, but is still relatively scarce. Most importantly, it is clear that more studies are needed – and these must employ better inferential methods – before general conclusions can be drawn. Overall, we hope that the present paper and special issue provide inspiration for future research and guidelines on best practices for its execution.

 

[Beta Test Team]

You're misunderstanding it.

Every change in morphology or cannabinoid profile isn't necessarily a phenotypic change. Many posters in this thread seem to think every little change is due to phenotype changes or expressions, and that's not necessarily the case..

[FONT=Arial, Helvetica, sans-serif][/FONT]I do think that a physical change is due to the phenotype being altered or just expressing differently .

If not, what else is it?

It's simply a difference found between two exact same gentoypes (clones), but not due to phenotypic plasticity.

For example, two clones, one flowering under 11 hour photoperiod and one under 13 hour photoperiod, while different in cannabinoid profile, can have the same phenotype expression. The difference is one got more DLI so it was able to produce more cannabindois than the other (which take a lot of energy to produce, energy from photons).

Another example could be better yield from the clone under 13 hours, again, just because the plant was able to produce more dry matter (from greater DLI) doesn't mean it's a phenotype difference (vs. the clone under 11 hours).

I'm not claiming the environment doesn't affect phenotype, it sure does, but I am claiming that not every difference between two clones is related to phenotype.

 

[Beta Test Team]

While this is about animals, it's pretty on-topic to this discussion and interesting:

Phenotypic differences in genetically identical organisms: the epigenetic perspective
http://hmg.oxfordjournals.org/content/14/suppl_1/R11.full

Abstract

Human monozygotic twins and other genetically identical organisms are almost always strikingly similar in appearance, yet they are often discordant for important phenotypes including complex diseases. Such variation among organisms with virtually identical chromosomal DNA sequences has largely been attributed to the effects of environment. Environmental factors can have a strong effect on some phenotypes, but evidence from both animal and human experiments suggests that the impact of environment has been overstated and that our views on the causes of phenotypic differences in genetically identical organisms require revision. New theoretical and experimental opportunities arise if epigenetic factors are considered as part of the molecular control of phenotype. Epigenetic mechanisms may explain paradoxical findings in twin and inbred animal studies when phenotypic differences occur in the absence of observable environmental differences and also when environmental differences do not significantly increase the degree of phenotypic variation.