An experiment to help determine the effect of different latitude on maturation time using a select cultivar

[Old Piney]

So here's some pictures, the first is my plants when I first noticed flowers pictured July 23.the second is gorilla ganja’s pictured yesterday August 19. And last is mine pictured August 13 View attachment 19051409

 

[gorilla ganja]

Your pics are not showing up @Old Piney

 

[Old Piney]

Ok here they are one at a time I struggle with tech. Mine July 23

 

[Old Piney]

Gorilla ganja August 19

 

[Old Piney]

Mine on August 13

 

[gorilla ganja]

What are the genetics of the strain you are both using?

It's a melody of Kushs x my Fantasmo Durban Poison Auto. This generation that we are growing is backcrossed to the plant pictured below.

May be able to check the sunrise and sunset times at various dates to determine how they compare and how each location is changing week to week over time.

Flowering onset is mainly determined by photoperiod. Up here at 55 N, this cultivar begins to flower about mid-August. On August 15, I have about 14 hours and 46 minutes of daylight and am dropping about 3.5 minutes a day right now.

If, for example, the CP of your variety is 14h, at a latitude of 40ºN it should begin to flower at the beginning of August, which is when daylight lasts 14 hours.
At a latitude of 55ºN it should do so 15-20 days later, at the end of August.

I think that is pretty close, give or take a few days.

The microclimate will play a part as well. Shorter days might speed up flowering but cold temps will slow down everything.

Absolutely. One of the main reasons it's hard to find cultivars that finish this far North is that by the time they begin to flower, the cold brings everything to a slow crawl, and a killing frost is not far off.

Elevation could also have an impact as well, what do you think?

I'm not sure elevation plays a role in flower onset, but the difference in elevation and the temp would affect how well they finish.

 

[gorilla ganja]

Ok here they are one at a time I struggle with tech

Just use the attach file button at the bottom left. You can then add several at a time.
What was your daylight length on July 23?

 

[gorilla ganja]

Good point. My plants are just in the ground and gorilla ganja’s are in his buddies greenhouse .He's grown them just outside so he should be able to tell us the difference in maturation time between the two

My buddy also has one outside. It's taken a beating from the wind and has several broken branches, but it looks like they are beginning to flower at the same time. It's a gamble up here if we can make it until mid-October to finish, so he's growing mainly in the greenhouse. He can control the heat in the most critical part of flowering.

 

[Old Piney]

Just use the attach file button at the bottom left. You can then add several at a time.
What was your daylight length on July 23?

14:32

 

[Old Piney]

My buddy also has one outside. It's taken a beating from the wind and has several broken branches, but it looks like they are beginning to flower at the same time. It's a gamble up here if we can make it until mid-October to finish, so he's growing mainly in the greenhouse. He can control the heat in the most critical part of flowering.

The greenhouse is good for our purpose here no cold to slow things down to @goingrey‘s point I've had plants out late and I know they just stop growing

 

[gorilla ganja]

So, it would seem like around 14.5 hrs is the critical photoperiod for this cultivar.

 

[Old Piney]

So, it would seem like around 14.5 hrs is the critical photoperiod for this cultivar.

Is that what you're at now

 

[Old Piney]

Himalayan Rasioi after a 27 degree f freeze it sprang back but it just stopped maturing

 

[gorilla ganja]

Is that what you're at now

On August 15, I have about 14 hours and 46 minutes of daylight and am dropping about 3.5 minutes a day right now.

Yes, around that, see the above quote.About 14.5 -15 hrs seems to be the sweet spot.
We peak out at losing 4 minutes of daylight a day, almost half a hour a week, until the autumn Equinox. At this time, we will be about equal in day length.

The Equinox (Vernal & Autumnal)​

There are only two times of the year when the Earth's axis is tilted neither toward nor away from the sun, resulting in a "nearly" equal amount of daylight and darkness at all latitudes. These events are referred to as Equinoxes. The word equinox is derived from two Latin words - aequus (equal) and nox (night). At the equator, the sun is directly overhead at noon on these two equinoxes. The "nearly" equal hours of day and night are due to refraction of sunlight or a bending of the light's rays that causes the sun to appear above the horizon when the actual position of the sun is below the horizon. Additionally, the days become a little longer at the higher latitudes (those at a distance from the equator) because it takes the sun longer to rise and set. Therefore, on the equinox and for several days before and after the equinox, the length of day will range from about 12 hours and six and one-half minutes at the equator, to 12 hours and 8 minutes at 30 degrees latitude, to 12 hours and 16 minutes at 60 degrees latitude.

 

[Old Piney]

dropping about 3.5 minutes a day right now.

Here currently they are dropping a little less than 2and 1/2 minutes a day and that rate will peak shortly on September 14 at 2.37 minutes a day drop

 

[Maria Sanchez]

My guess is that the lower latitude plant will flower first, due to hitting the critical day hours earlier.
And of course it's more likely to not meet the nasty fall weather as soon, too.
Whereas the higher latitude plant will have a hard time -- starting later, and possibly hitting bad weather before she's done.

Since the two plants are just the same cultivar, not cuttings / clones, then there will be variation there.
Unless they are a nice IBL that breeds true...
Would be great to run this experiment with cuts/clones.

 

[kendermag]

So, it would seem like around 14.5 hrs is the critical photoperiod for this cultivar.

 

[Old Piney]

My guess is that the lower latitude plant will flower first, due to hitting the critical day hours earlier.
And of course it's more likely to not meet the nasty fall weather as soon, too.
Whereas the higher latitude plant will have a hard time -- starting later, and possibly hitting bad weather before she's done.

Since the two plants are just the same cultivar, not cuttings / clones, then there will be variation there.
Unless they are a nice IBL that breeds true...
Would be great to run this experiment with cuts/clones.

And what do you suppose would happen if you grew this strain down near the equator? Having a critical photoperiod of 14.5 hrs, would it just start flowering in about six week regardless of when you planted it ?

 

[Old Piney]

View attachment 19051549

Indeed it does, I was wrong with my prediction I thought there was a little more to it than just a photoperiod that the plant just through a switch at ,like sensing how fast the daylight is dropping. That's me I question everything

 

[kendermag]

I thought there was a little more to it than just a photoperiod that the plant just through a switch at ,like sensing how fast the daylight is dropping.

I think it is also important, but in this case, I think the dropping is enough for them to start flowering, it probably has little effect between 40º and 55º.

But if you had this plant indoors with a static 14.5h photoperiod, the start of flowering would be much slower, I think the plant would stretch much more... that is, the pre-flowering period would be longer.

It is similar to what happens with equatorial sativas, if for example they have a CP of 12.5, they take a long time to start flowering near the equator with photoperiods close to 12 hours and their stretch is also very great.

On the other hand, if you planted your plant near the equator, it would begin to flower as soon as it reached maturity, perhaps 4-6 weeks as you say. The plant would also be smaller.