Growing outdoors and Understanding Light hours.

[The Hash Nibbler]

Heya Guys, seen a lot of questions around about Outdoor growing and Photoperiods (I had some myself.hehe) , and thought this may be of interest to people wanting to know questions like.....

 

When do I put my plants out?................................

 

If I put them out now already vegged , will they flower or RE-Veg?.............................

 

How early do I have to put my plants out to have Christmas buds?..........................

 

Can I plant out of season?..................

 

Etc, Etc.......

 

Please be aware that these guys grow in the Northern Hemisphere , so Months are not applicable here and latitude may vary depending on your location........

 

Quote:

 

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-

 

http://en.wikipedia.org/wiki/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.

 

Here are the Latitudes for a few North American, European and Australian cities to show a example of the vast differences in latitude-

 

Darwin, Australia-12.4° S

Miami, Florida-25.8° N

Houston, Texas-29.7° N

Los Angeles, California-34.1° N

Atlanta, Georgia-33.9° N

Canberra, Australia-35.3° S

San Francisco, California-37.8° N

Reno, Nevada-39.5° N

Naples, Italy-40.8° N

Chicago, Illinois- 41.9° N

Boston, Massachusetts-42.4° N

Toronto, Ontario-43.6° N

Ottawa, Ontario-45.3° N

Seattle, Washington-47.6° N

Vienna, Austria-48.2° N

Vancouver, British Columbia-49.2° N

Calgary, Alberta-51.1° N

Warsaw, Poland-52.2° N

Amsterdam, Netherlands-52.3°

Edmonton, Alberta-53.3° N

Anchorage, Alaska-61.2° N

 

The Photoperiod sensitive strains of Cannabis are each geneticly programmed to start blooming when day shortens to a certain length*.

When these various strains are bred, they become acclimated to that latitudes photoperiod, they are bred to bloom and harvest before that areas climate becomes too cold and dark(or wet), usally to avoid major mold problems, or harsh freezing weather.

*Many experts agree that it is actually the length of the dark period that matters to plants.

 

When you take a plant that was bred in one location, and move it to a similar Latitude, say from 42° N to 43° N the plant should harvest at nearly the same time. But if you take a plant from 42° N to 50° N, its possible that the plant may not harvest early enough to beat Winter further up north.

__________________________ Unquote.

 

Was posted by a grower on another site, so thanks for the info, Backcountry from ICmag. =)

www google.com.au/url?q=http://forum.grasscity.com/outdoor-marijuana-growing/&sa=X&ei=Y7iHTrr4EIeKmQW1j_Eo&ved=0CCoQ6QUoADAD&usg=AFQjCNHIfu6L8K9xHlpi5Enfw3MLEgvPNw

Found info on Grasscity, as I was doing some research into my areas light times and lattitude.

If this little bit of Info gets ya curious, there are whole sections on this in most GOOD growing books, eg. Ed Rosenthal, Robert Clarke etc.....

Amazing what you can do Outdoors if you understand the light and what your plant wants and needs......

Peace. Gh72

[Delta 9]

G'day Hoppy, some nice info there. Do you have a reference or link to your quote mate?

[The Hash Nibbler]

Post has been editted delta, link and credit to author... peace. Gh72

[Delta 9]

Sweet, cheers mate. I'm going to take the dogs for a long walk today through the local foothills. See if I can find a nice spot that gets a decent amount of sun... for a picnic

[-RiverRat-]

Good post GrassHopper . While were at it I'll add this UV graph showing the diference in the strength of the sun as you get nearer to the equator. For what the tropics lacks in daylight hours it makes up fot it with fat resiny head prodicing UV rays

 

 

 

Image obtained from.

 

http://www.bom.gov.au/jsp/ncc/climate_averages/uv-index/index.jsp

 

Month to Month averages available and other data.

 

 

Dalight Calculator

 

Just dial in your latitude.

 

http://astro.unl.edu/classaction/animations/coordsmotion/daylighthoursexplorer.html

 

 

Edited October 2, 2011 by -RiverRat-

[smashed1]

good info gh ,, now i might be able to grow a bloody plant

[Reverend]

If you follow this link it will give you the sun rise and hours etc.

 

http://www.gaisma.com/en/dir/au-country.html

 

 

 

Cheers

[sargentscraps]

Instead of starting a new thread I thought I'd post my though/question here.

A lot of the time when outdoor plants are started indoors they run at 18/6 or 24 so eventually when they're put outside they go to flower for a short amount of time before they realise the days light is increasing so they re-vert back to veg. Now I was thinking the other day, say the current daylight hours are 13 hours roughly or whatever it is, If you were to switch your plants onto maybe 11/13 (11 on / 13 off) for 3 days or so then put them outside where it is 13 hours and the days are getting longer, would this reduce the amount of turnaround time needed for the plant? Because instead of putting it from 18/6 to 13 hours of light where it instantly notices the massive shortage in daylight hours you shock them for three days or so inside so then when you put them out they realise the days are getting longer by at least an hour or so rather than the shock of 4 hours of light shortage or whatever it is.

I realsie I could have made that very confusing but if you have any knowledge or thoughts please share.

[The Hash Nibbler]

Heya Sarge , I think I see what your getting at. Mate, Id just veg em longer inside and put em out once light hours hit about 14 hours or so. Not much will go to flower with that. To put them to 11 on and 13 off would start to trigger the flower period, even though they wont show in those few days, so they will still go to flower outside then re-veg later. Might be interesting to see what happens in reality though.

I am finding with Indica dominant strains that once they are about 4/5 weeks into flower they will not reveg and just finish flowering , I just pulled a Pc been in for 9 weeks in the greenhouse and got a scrog thats been in flower 4/5 weeks showing no signs of re-veg. Satiis are a different story.

 

I did a bit of reading around but best info I found was from doing it out the back and watching the plants. I am looking to see if starting early will allow me to have chrissy buds, just from vegging fully under cfl's and popping em out end of July. So far so good, but its gonna be trial and error depending on strain and getting ya latitude worked out and matching that to when you throw em out.

Imo, ha ing em in 18/6 then going to 11/13 for a few days , then outside to 13 hours + will maybe shock em into doing naughty things, even outside they dont like being messed around so quick.

 

Im experimenting , will pop up some pictures when I get on the puter later. Peace. Gh72

Edited October 13, 2011 by Grasshopper72

[louise]

Good starting info for outdoor growers GH. I'd add that growers, particularly those in the south of the country, should account for the civil twilight periods (first light to sun rise and sun set to last light) when estimating day length. Using sun rise to sun set figures would give me a figure that was nearly an hour short of the actual day length.

 

The link Reverend posted lists both sun rise/set and civil twilight (dawn/dusk) as does this one which you can produce a printable chart of the day length over a year LINKY.