Why Do Plants Stretch?.

brimck325 said:

most indicas are from regions with scrub like vegetation and cold nights, sativas are from equatorial areas where surrounding vegetation grows rampant with warm temps. therefore indica's don't need much extra height to achieve pollination, where sativa's do. that's my thought on it anyway.

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this is hella fucking plauseable.. I never looked at it like that... my theory is indicas grow in mountainous areas with high uv and co2... seems everything grown at elevation is slightly shorter more robust and squatter... while plants that grow in tropical humid or desert dry areas have slimmer leaves {sativa like} also in most strains of cannabis photoperiod dictates when bloom begins right... but in tropical areas the sun is never up longer then 13 hours a day this causes lots of tropical sativas to dissregaurd light cycles and veg until they are damn well ready to bloom.. some sativas take a month to even begin flower and will bloom for 16 or more weeks... I think this is responsible for the more extream stretches of sativas.... also if u notice most sativa strains will foxtail, and there flowerers want to be has far away from the main/central stem has possible...... while indicas are much more dense with the flowers wanting to stay closer to the main stem.. I wonder why that is?

theexpress said:

this is hella fucking plauseable.. I never looked at it like that... my theory is indicas grow in mountainous areas with high uv and co2... seems everything grown at elevation is slightly shorter more robust and squatter... while plants that grow in tropical humid or desert dry areas have slimmer leaves {sativa like} also in most strains of cannabis photoperiod dictates when bloom begins right... but in tropical areas the sun is never up longer then 13 hours a day this causes lots of tropical sativas to dissregaurd light cycles and veg until they are damn well ready to bloom.. some sativas take a month to even begin flower and will bloom for 16 or more weeks... I think this is responsible for the more extream stretches of sativas.... also if u notice most sativa strains will foxtail, and there flowerers want to be has far away from the main/central stem has possible...... while indicas are much more dense with the flowers wanting to stay closer to the main stem.. I wonder why that is?

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to answer my own question... sativas originated from the tropics of south east asia.. a very constently humid climate.... I think sativas are of a more loose/open/fluyy nature for mold resistence reasons...... there leaves are much more skinnier to let more light pass threw the very tall gangly plant... and also to give it a break from the tropical sun,,,,, indicas coming from high altitude climates are super dense.... I donno why they are that way but I know that most high altitude places are much less humid if not dry compared to tropics... so no real threat of mold in its natural enviorment... thus allowing dense flower clusters....... everything originated from cannabis sativa.. so it would be interesting how long would it take a sativa taken to elevation to become an indica???? id imagine many many many generations........ prolly only a small amount would survive there life cycle threw man selected breeding and even less would survive if left to nature... but with every passing generation becoming more climeteized to its surroundings

another interesting question I have is were {which country, region} did the first indica appear.... its known the cannabis plant originated in asia and the chinease people have the old documented use of cannabis so where did the first indica evolve?..... was it in the mountains of Afghanistan?... or the himmalayas of india???? I think the answer to this question would be whoever the chinease started trading with first... this would lead me to beleave india due to closer proximity... undoubtobly the chinease gave the Indians there first cannabis seeds since it was so important to there people.. I beleave the chinease refer to the cannabis plant has "the giver of delight" its very important to them... as it is me :] the Indians refer to it has "joy giver"

Plants stretch as a shade avoidance effect.

When one branch is under the canopy, it will stretch until it sees direct sunlight and then stop stretching.

This is because of the phytochrome system.

They will stretch more when R:FR ratio is low.

nitrogen/phosphorous ratio plays a role. too high a ratio (with ammoniacal nitrogen) and we have stretch. Too low a ratio can produce crazy tight internodes with tiny leaves.

kend said:

nitrogen/phosphorous ratio plays a role. too high a ratio (with ammoniacal nitrogen) and we have stretch. Too low a ratio can produce crazy tight internodes with tiny leaves.

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Sort of true, but only because ammonical nitrogen fertilizers have higher concentrates of phosphates in them. Higher ratios of phosphorus adds to the stretch as well.

http://www.gpnmag.com/what-really-causes-stretch
http://www.gpnmag.com/sites/default/files/GPN Jan '02 -NC State.pdf From an NC State study....

[h=2]"Conclusions[/h]

When all of these results are put together, it is clear that
the form of nitrogen did not govern plant size. Repeatedly, the differences in
plant growth were a consequence of the amount of phosphorus supplied to the
plants, not the form of nitrogen. Going back to the original question,
“Does ammonium-nitrogen really cause plant stretch,” the answer
would have to be no. Differences in plant height among the many fertilizers
varying in ammonium-nitrate proportion are controlled by the phosphate —
low phosphate levels result in compact plants, high phosphate levels result in
tall plants.
Fertilizers with high proportions of their nitrogen in the
nitrate form typically contain little or no phosphate, resulting in compact
plants and leading to the incorrect assumption that nitrate nitrogen causes
compactness. Fertilizers with high proportions of nitrogen in the ammonium form
(33 percent or more) invariably contain high levels of phosphate. These
fertilizers yield the more luxuriant growth to which we are accustomed and
result in the belief that ammoniacal nitrogen causes stretch.
Thus, if compact plants are your goal, you should limit the
amount of phosphorus applied to the plants; conversely, if full plants are your
goal, you should apply fertilizers containing the appropriate levels of
phosphorus."

This makes sense because nitrates and phosphates are both negatively charged and thus can antagonize each other. Ammonium is a positively charged ion so it does not antagonize phosphate or nitrate.

Ammonium does, however, antagonize potassium, calcium, and magnesium as they are positively charged ions. Solutions with a high percentage of nitrogen as nitrate also generally also contains a lot more K+ ions. Ammonium also directly shares the cellular K+ channels.

That being said, I don't think P level is directly related to stetch rate. As a signal, the level of phosphate controls the partitioning of carbs. With low P, more of the sugars produced will be stored as starch, whereas with abundant P, more sugar will be used for growth.

plaguedog said:

"Fertilizers with high proportions of their nitrogen in the
nitrate form typically contain little or no phosphate, resulting in compact
plants and leading to the incorrect assumption that nitrate nitrogen causes
compactness. Fertilizers with high proportions of nitrogen in the ammonium form
(33 percent or more) invariably contain high levels of phosphate. "

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churchhaze said:

This makes sense because nitrates and phosphates are both negatively charged and thus can antagonize each other. Ammonium is a positively charged ion so it does not antagonize phosphate or nitrate.

Ammonium does, however, antagonize potassium, calcium, and magnesium as they are positively charged ions. Solutions with a high percentage of nitrogen as nitrate also generally also contains a lot more K+ ions. Ammonium also directly shares the cellular K+ channels.

That being said, I don't think P level is directly related to stetch rate. As a signal, the level of phosphate controls the partitioning of carbs. With low P, more of the sugars produced will be stored as starch, whereas with abundant P, more sugar will be used for growth.

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I wouldn't say that P is the only factor here, but the study clearly shows that nutrient formulas with a P percentage greater than one percent are a factor. All these crazy NPK ratios's you see in "MJ specific foods" are WAY out of wack, and always have been.

sativa strectch, because thats what they do, they dont have a winter persay, if your indicas do you have some other serious issues

Sativas stretch more than indica so some of the sati as will double there height when 12/12 is interdicted indicas will not do this so matey some of your plants are like 70/30 sati a or higher

I think this stretch can either be good or bad, depending on your setup.

With my set up, I need them to stretch. The taller the plant, the bigger the bud; in my situation anyway. Because the lights are 5 feet above the reservoir. My tallest plants always end up getting the fattest heaviest buds.