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Finishing times, Photoperiod, Latitude, and how it all works!!


 

#1
dankohzee

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  • Dingus, alabonga, bongwater923 and 8 others like this

#2
iAMtheLiquor

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Thanks Dank. Beautiful find. Definitely a good and useful read. + rep for sure.

#3
SensiHead

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so flowering usualy starts around 9-10 hours of darkness?

#4
nevesone7

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Great info dankohzee, it answers a lot of questions I have been having on my grow this year. Explains clearly why (for us from the USA that order from overseas seedbanks) might end up with strains doing strange thing's here in California...I started with 11 in the ground on April 15th, lost 1, two showed male in the last two weeks, 7 confirmed females (some now appear to be going back to veg, but a couple look to be full flowering) and one still unknown but is a beautiful MJ plant in any case. Thanks for the post!

Edited by nevesone7, 25 June 2009 - 04:24 AM.


#5
greenmeany

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#6
some dude

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Man, great info. Thought I'd give it a little bump.

#7
prodigyru

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#8
nevesone7

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I 2nd that, it's great info and should be right up there with all the other great info threads at the top. let's find out how we can make it a sticky and get it done.

#9
wraughbit

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sticky sticky sticky!

#10
prodigyru

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#11
growerruney

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i agree, backcountry has some amazing grows on icmag.

#12
Cenabite

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NICE ONE!!

Question, So after reading your post i would like to measure the current Photoperiod, you mentioned dusk, At what point do you consider it lights out? because this could be anywhere in between when i lose direct sunlight around 3 to when the sun goes down, to when it actually gets dark..

Your measurements seem to be pretty exact, Are you measuring by sunset?

Thanks and again awesome post! +rep and admins we need a sticky ichy on this post...


Btw im in Tampa area 27° 58' N 82° 32' W



:gc_rocks:

#13
prodigyru

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#14
SensiHead

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this post is about all the variables. strain, climate, location etc. there is no definite "flowering time" for anyone. o yeah and i nominate this for a sticky! anyone else?


yea ok, thx, i meant to say do indicas usualy start flowering around 9-10 hours of darkness or more?

im at 45 N, and it seems they're startin to show sex (blueberry 80% indica and mango 90%+ indica)

#15
SensiHead

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yep this post's obviously worth a sticky!

#16
dankohzee

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#17
cantharis

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Thanks for keeping it bumped guys. Soon the main question in outdoor will be about when 12/12 is, lol. I doubt they'll make it a sticky though because it's borrowed. Maybe if someone would rewrite it in their own words...


Yep, that´s right.

When does 12/12 occur in my area?? will replace is it too late? as the favourite question of noobs who can´t be bothered to read the stickies.

#18
dankohzee

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#19
nevesone7

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Nice to see this moved to a sticky, it answered lot's of questions I had and I'm sure it will answer many more for others.

#20
TexasToaster

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NICE ONE!!

Question, So after reading your post i would like to measure the current Photoperiod, you mentioned dusk, At what point do you consider it lights out? because this could be anywhere in between when i lose direct sunlight around 3 to when the sun goes down, to when it actually gets dark..

Your measurements seem to be pretty exact, Are you measuring by sunset?

Thanks and again awesome post! +rep and admins we need a sticky ichy on this post...


Btw im in Tampa area 27° 58' N 82° 32' W


O Z covers that here:


Here is a chart comparing the length of day for 4 areas, over the year. The first number is the length of day(meaning sunrise to sunset), the second number includes the twilight time before sunrise and after sunset(basicly the total length of visable light)-

----- Houston, TX 29.7°N--------Humbolt county, CA 40° N------Eugene, OR 44.1°N--------Vancouver,BC 49.2°N

Dec 21--10h 14m/11h 07m------------9h 22m/10h 23m--------------8h 52m/9h 58m--------------7h53m/9h 27m

Jan 21--10h 33m/11h 24m------------9h 51m/10h 49m--------------9h 26m/10h 30m------------8h 54m/10h 05m

Feb 21--11h 19m/12h 07m-----------10h 58m/11h 53m-------------10h 46m/11h 45m-----------10h 31m/11h 36m

Mar 21--12h 58m/12h 56m-----------12h 10m/13h 04m-------------12h 11m/13h 09m-----------12h 13m/13h 16m

Apr 21--13h 03m/13h 52m-----------13h 29m/14h 25m-------------13m 44m/14h 45m-----------14h 04m/15h 12m

May 21--13h 45m/14h 57m-----------14h 31m/15h 33m-------------14h 45m/16h 06m-----------15h 34m/16h 53m

Jun 21--14h 03m/14h 57m-----------15h 57m/16h 05m-------------15h 30m/16h 43m-----------16h 14m/17h 40m

Jul 06--13h 58m/14h 52m-----------15h 00m/16h 06m-------------15h 22m/16h 34m-----------16h 04m/17h 28m

Jul 21--13h 45m/14h 57m-----------14h 31m/15h 33m-------------14h 45m/16h 06m-----------15h 34m/16h 53m

Aug 06--13h 26m/14h 17m-----------14h 09m/15h 10m-------------14h 24m/15h 29m-----------14h 53m/16h 06m

Aug 21--13h 03m/13h 52m-----------13h 29m/14h 25m-------------13m 44m/14h 45m-----------14h 04m/15h 12m

Sep 06--12h 36m/13h 24m-----------12h 53m/13h 48m-------------12h 58m/13h 57m-----------13h 09m/14h 14m

Sep 21--12h 10m/12h 56m-----------12h 10m/13h 04m-------------12h 11m/13h 09m-----------12h 13m/13h 16m

Oct 06--11h 43m/12h 31m-----------11h 32m/12h 27m-------------11h 28m/12h 26m-----------11h 21m/12h 25m

Oct 21--11h 19m/12h 07m-----------10h 58m/11h 53m-------------10h 46m/11h 45m-----------10h 31m/11h 36m

Nov 06--10h 52m/11h 42m-----------10h 13m/11h 11m-------------10h 00m/11h 01m------------9h 35m/10h 43m

Nov 21--10h 33m/11h 24m------------9h 51m/10h 49m--------------9h 26m/10h 30m------------8h 54m/10h 05m

Dec 21--10h 14m/11h 07m------------9h 22m/10h 23m--------------8h 52m/9h 58m-------------7h 53m/9h 27m

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?
____________________________

Dawn is when you would begin counting daylight and Dusk is when you would stop counting. The twilight referred to is listed as civil twilight. It's basically about a half hour before Sunrise, Dawn, and a half hour after Sunset, Dusk. So just add an hour to the difference between sunrise and sunset to get your photoperiod, Daylight.

From now (since June 21) until Dec 21, the days are getting shorter and the nights are getting longer.

It starts getting dark around 3pm in Tampa? Houston is at 29.7N, so it shouldn't be much different from their time...except for the time zone difference. Quantity should be about the same. It's not "Dark" in Houston until a little before 9pm. Are you behind a high-rise?

You can Google "When is my civil twilight?" or "Civil Twilight calculator" for your specific times.

Edited by TexasToaster, 31 July 2009 - 04:09 PM.
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