12/12 does not apply to outdoor growing

ganga gurl420

Well-Known Member
I've been reading a lot of posts since I've joined and seen a lot of bad advice as far as when to put out plants and when they flower.
Most know the 12/12 rule for indoor grows and most think that this applies to outdoor as well.

So I'm going to copy and paste this and hopefully some of you will read this and have a better understanding so that no one is steered in the wrong direction.

*Copy & paste from a random website*

Does 12/12 mean anything outdoors?
Often I have seen new members(or members mostly experienced in indoors) post threads asking when 12/12 occurs outdoors. Often they say they are looking for the time of the season when their plants will start blooming outdoors, many times they are trying to use this date(Sept 21 Equinox) plus the strains indoor finishing time to determine the outdoor finishing time.

But of course it doesn't work that way, we know that most strains have started blooming long before Sept 21st, but there is even more reason why indoor finishing times can't be applied outdoors.

One thing to realize is that as the day lights length shortens, the plants speed up their blooming, since most plants start blooming long before 12/12, outdoor plants will take longer to set into blooming and to finish than their indoor grown sisters would. So basically, unless you live very near to the Equator, indoor finishing times will not be applicable outdoors.

Finishing times, Photoperiod, Latitude, and how it all works!!
We all know the basics of vegging and blooming Cannabis..... when the day is long and the night is short the plant concentrates on vegging(growing), when the day length shortens enough, the plant starts to bloom.

But how does all this work?
Why does the same strain finish at different times in different parts of the world? Does 12/12 really mean anything outdoors? Why is Latitude(or "Lat") so important to some growers? What is a "Auto-flowering" plant?

Lets get into the meat of the subject shall we?..............

Photoperiod
The first thing to cover here is Photoperiod- Photoperiod is the ammount of time there is light in a 24 hour period. In Cannabis growing, Photoperiod is typically shown like this- 12/12 or 16/8, or 18/6, etc. The first number is usually the length of the lighted period, the second shows the balance of the 24 hours that is dark.

Outdoors the sun controls the Photoperiod. Its length changes through the seasons according to the movements of the sun in the sky, a matter of fact it causes the change in seasons. This brings us to......

Photoperiodism
Photoperiodism is the reaction of many flowering plants(including Cannabis) to changes in Photoperiod. Plants that experience Photoperiodism have pigment cells called Phytochrome that monitor the ammounts of light being absorbed by the plants(specificly the red end of the spectrum), and the length of day. Signals from the Phytochrome tell the plant to do many things, including to grow, bloom, and in the case of some trees, to loose their leaves and go dormant in Autum.

Most of these plants fall into three catergories concerning blooming times, that being- long day plants(blooms as day gets longer), short day plants(blooms as day gets shorter), and day neutral plants(blooming is not according to light cycles).

All Cannabis varieties are either "Short day", plants or "Auto-flowering" (known as "Day neutral" outside of the Cannabis community). So called "Auto-flowering" plants do not seem to take their blooming cues from the sun, and thus should be considered "Day neutral", as most seem to be geneticly programmed to bloom according to age insted.

----------------------------------------------------------------------

The Sun, Latitude, and why the same plants finish different times at different points on the globe

The year as we know it is basicly the time it takes for the Earth to make a complete loop around the sun. As the Earth makes this loop it shifts on its axis, so that either the northern half or southern half(Hemispheres) have the longer photoperiod.



The shortest day of the year is called the Winter Solstice, this day occurs on December 21st in the northern half of the world, on the same day in the southern hemisphere they will have their Summer solstice, the longest day of the year. On June 21s it will be reversed, with the longest day of the year in the north(Summer solstice), and the shortest day in the south(Winter solstice).

Two days of the year are known as the equinoxes, one occurs March 21st and one on September 21st. These days represent the halfway point between the longest and shortest days of the year, on these days the day length is almost exactly 12/12 all over the world. If you are in the Northern hemisphere, Mar. 21 is the first day of Spring and September is the first day of Autum, reverse these dates in the southern hemisphere.

Latitude
Latitude is the east-west lines you see on a globe or map of the earth, they are spaced about every 111 Kilometers starting at 0 degrees at the Equator, and graduating north and south from there (every 111 KM) to the north pole(90 Degrees North) and South pole(90 Degrees south).

Here is a link to Wikpedia explaining Latitude-

Latitude

At the Equator the length of day doesn't change much from month to month, at both Solstices the length of day is about 12 hours, at both Equinoxes it is about 12 hours, almost perpetual 12/12.

Now lets take a look at Portland Oregon, this city sits near 45.4° N, which is about exactly halfway between the Equator(O°) and the North pole(90°N).
At the Winter solstice, the length of day is 8h 41m, at Summer solstice the day length is 15h 41m, and at the Equinoxes it is 12h 12m.

And now lets look at Anchorage Alaska, this city sits at 61.2° N, a little over 2/3 of the way to the North pole(90° N) from the Equator(0°).
At the Winter Solstice the day length is 5h 27m, at Summer solstice the day length is 19h 22m, and the Equinoxes are 12h 18m.

As you move away from the equator(either north or south), you see more distictness between the seasons and the length of days during those seasons.

Generally the closer you are to the Equator, the less difference there is between the length of day on the Solstices(the longest and shortest days of the year.

The further you are from the Equator, the more difference there is in length of day between the Solstices, making the Summer shorter and shorter, and the longest day of the year longer and longer the further you go from the eternal 12/12 of the Equator.


--

Length of day Vs. Length of visable light
When you see people describe outdoor Photoperiod, they often use the "Length of day" to describe it. "Length of day" is defined legally as the time between sunrise and sunset, the problem with using this figure is that it doesn't count the visable light known as "Twilight", that occurs before sunrise, and after sunset, the day may actually be 1 hour(or more) longer!
Cannabis plants do have a cut off point where they no longer consider fading light as "day", I am sure this tolerence point is different for each strain grown. Obviously a full moon is not bright enough to affect Cannabis plants, but who really knows where cut off is?.
 

thewanderingjack

Well-Known Member
Interesting stuff... I'd also gotten the 12/12 in my head somewhat... I knew that outdoors the plants reacted to the shortening days more... which really seemed obvious... exact 12/12 when you account for twilight and other factors is unlikely... but you can't deny the effect of thos days getting much much shorter...

But I still thought NATURAL outdoor growers had to wait closer to the Autumnal equinox for real "flowering."

I realized I haven't seen many natural outdoor growers... prety much all of them used light dep. SO, yeah... The More You Know. Thanks Ganja Gurl (I think you were in that thread weren't you?... this is great follow up)
 

ganga gurl420

Well-Known Member
Well if you figure equinox happens in late sep,.....
And you look at finishing times outdoors on any breeder's site it will say usally
Late sep or mid oct. November would be for your super long flowering sativas.

Most short flowering indicas are done at the Equinox.
 

thewanderingjack

Well-Known Member
So... would it be more fair to say that outdoors, planted and mature (veg) before the summer solstice will start flowering as the days get shorter, i.e. just after it?

Also, IF I plated as days are in decline, and summing you know 30 days for sexual maturity... would my plant start to flower after the 30 days?

(By start I mean like just start... pre/early flower)

Thanks in advance :)
 

ganga gurl420

Well-Known Member
This is tricky. I will do my best.

June 1st is when they say it is best to plant outdoors. Sooner then this can cause early flowering and then as the days get longer (closer to summer solstice) the plant would re veg then go back to flower like normal.

The only way to avoid early flowering is either starting your plant outdoors with no supplemental lighting which I've seen people do as early as april.
Or if you start them Indoors you would have to adjust your lighting to match outside
Or third option would be to have supplemental lighting outdoors on the plant.

So to sum it up.... plants should definitely be outdoors and adjusted before the summer solstice.
Most plants will go into full flower by the end of july or the first two weeks of Aug

Yes you need the plant to be sexually mature before mid july.

There is this window of opportunity for outdoors. I'm always in the ground by mid may.
 

thewanderingjack

Well-Known Member
Sooner then this can cause early flowering
Can you explain why? maybe It's because I was already thinking in terms of keeping the plant at the same light times as it would out door, or planting straight outdoors, I don't get this... unless it's if I switch it, based on indoor light sched vs oudoor light sched, causing early flower.

In my mind If I planned to head outside with it (start indoors) I would try to match outdoor lights and time pretty much from the start and if possible the twilight cycles as well... that's ust good plant management :)
 

ganga gurl420

Well-Known Member
First to clarify I adjust my plants slowly to the outdoor lighting schedual but have still had them early flower then re veg even in mid may.

There is not enough sunlight yet before July 1st to keep them in veg. It really depends on how sensitive the strain is to photoperiods.

But in short if you want massive yields the sooner you get them outside (around July 1st) the bigger your harvest in fall.

If you live In a warm climate and frost is not a factor you can have them outside in march even as long as you put some sort of supplemental lighting on them. Solar lights work well for this.

Some people keep lights on them outdoors until the summer solstice and then let nature take over.
 

ganga gurl420

Well-Known Member
There is also a guy in the outdoor section (757) that pops his bean around the first of April and never has any lighting. He plants in 1000 gallon smart pot and gets around 10#.
But that is because the plant has always been on that lighting schedual.
It just depends on how you start them.
 

ganga gurl420

Well-Known Member
Sadly because of the late frosts I get .... I will only be getting somewhere around 5 a plant.

And your welcome.
 

Jaypjay

Member
I've been reading a lot of posts since I've joined and seen a lot of bad advice as far as when to put out plants and when they flower.
Most know the 12/12 rule for indoor grows and most think that this applies to outdoor as well.

So I'm going to copy and paste this and hopefully some of you will read this and have a better understanding so that no one is steered in the wrong direction.

*Copy & paste from a random website*

Does 12/12 mean anything outdoors?
Often I have seen new members(or members mostly experienced in indoors) post threads asking when 12/12 occurs outdoors. Often they say they are looking for the time of the season when their plants will start blooming outdoors, many times they are trying to use this date(Sept 21 Equinox) plus the strains indoor finishing time to determine the outdoor finishing time.

But of course it doesn't work that way, we know that most strains have started blooming long before Sept 21st, but there is even more reason why indoor finishing times can't be applied outdoors.

One thing to realize is that as the day lights length shortens, the plants speed up their blooming, since most plants start blooming long before 12/12, outdoor plants will take longer to set into blooming and to finish than their indoor grown sisters would. So basically, unless you live very near to the Equator, indoor finishing times will not be applicable outdoors.

Finishing times, Photoperiod, Latitude, and how it all works!!
We all know the basics of vegging and blooming Cannabis..... when the day is long and the night is short the plant concentrates on vegging(growing), when the day length shortens enough, the plant starts to bloom.

But how does all this work?
Why does the same strain finish at different times in different parts of the world? Does 12/12 really mean anything outdoors? Why is Latitude(or "Lat") so important to some growers? What is a "Auto-flowering" plant?

Lets get into the meat of the subject shall we?..............

Photoperiod
The first thing to cover here is Photoperiod- Photoperiod is the ammount of time there is light in a 24 hour period. In Cannabis growing, Photoperiod is typically shown like this- 12/12 or 16/8, or 18/6, etc. The first number is usually the length of the lighted period, the second shows the balance of the 24 hours that is dark.

Outdoors the sun controls the Photoperiod. Its length changes through the seasons according to the movements of the sun in the sky, a matter of fact it causes the change in seasons. This brings us to......

Photoperiodism
Photoperiodism is the reaction of many flowering plants(including Cannabis) to changes in Photoperiod. Plants that experience Photoperiodism have pigment cells called Phytochrome that monitor the ammounts of light being absorbed by the plants(specificly the red end of the spectrum), and the length of day. Signals from the Phytochrome tell the plant to do many things, including to grow, bloom, and in the case of some trees, to loose their leaves and go dormant in Autum.

Most of these plants fall into three catergories concerning blooming times, that being- long day plants(blooms as day gets longer), short day plants(blooms as day gets shorter), and day neutral plants(blooming is not according to light cycles).

All Cannabis varieties are either "Short day", plants or "Auto-flowering" (known as "Day neutral" outside of the Cannabis community). So called "Auto-flowering" plants do not seem to take their blooming cues from the sun, and thus should be considered "Day neutral", as most seem to be geneticly programmed to bloom according to age insted.

----------------------------------------------------------------------

The Sun, Latitude, and why the same plants finish different times at different points on the globe

The year as we know it is basicly the time it takes for the Earth to make a complete loop around the sun. As the Earth makes this loop it shifts on its axis, so that either the northern half or southern half(Hemispheres) have the longer photoperiod.



The shortest day of the year is called the Winter Solstice, this day occurs on December 21st in the northern half of the world, on the same day in the southern hemisphere they will have their Summer solstice, the longest day of the year. On June 21s it will be reversed, with the longest day of the year in the north(Summer solstice), and the shortest day in the south(Winter solstice).

Two days of the year are known as the equinoxes, one occurs March 21st and one on September 21st. These days represent the halfway point between the longest and shortest days of the year, on these days the day length is almost exactly 12/12 all over the world. If you are in the Northern hemisphere, Mar. 21 is the first day of Spring and September is the first day of Autum, reverse these dates in the southern hemisphere.

Latitude
Latitude is the east-west lines you see on a globe or map of the earth, they are spaced about every 111 Kilometers starting at 0 degrees at the Equator, and graduating north and south from there (every 111 KM) to the north pole(90 Degrees North) and South pole(90 Degrees south).

Here is a link to Wikpedia explaining Latitude-

Latitude

At the Equator the length of day doesn't change much from month to month, at both Solstices the length of day is about 12 hours, at both Equinoxes it is about 12 hours, almost perpetual 12/12.

Now lets take a look at Portland Oregon, this city sits near 45.4° N, which is about exactly halfway between the Equator(O°) and the North pole(90°N).
At the Winter solstice, the length of day is 8h 41m, at Summer solstice the day length is 15h 41m, and at the Equinoxes it is 12h 12m.

And now lets look at Anchorage Alaska, this city sits at 61.2° N, a little over 2/3 of the way to the North pole(90° N) from the Equator(0°).
At the Winter Solstice the day length is 5h 27m, at Summer solstice the day length is 19h 22m, and the Equinoxes are 12h 18m.

As you move away from the equator(either north or south), you see more distictness between the seasons and the length of days during those seasons.

Generally the closer you are to the Equator, the less difference there is between the length of day on the Solstices(the longest and shortest days of the year.

The further you are from the Equator, the more difference there is in length of day between the Solstices, making the Summer shorter and shorter, and the longest day of the year longer and longer the further you go from the eternal 12/12 of the Equator.


--

Length of day Vs. Length of visable light
When you see people describe outdoor Photoperiod, they often use the "Length of day" to describe it. "Length of day" is defined legally as the time between sunrise and sunset, the problem with using this figure is that it doesn't count the visable light known as "Twilight", that occurs before sunrise, and after sunset, the day may actually be 1 hour(or more) longer!
Cannabis plants do have a cut off point where they no longer consider fading light as "day", I am sure this tolerence point is different for each strain grown. Obviously a full moon is not bright enough to affect Cannabis plants, but who really knows where cut off is?.
Thank you so much for this, I've been looking for the answer to this question for months now, I'm at latitude 53 and the flowering times just didn't add up for me. Thanks again!
 
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