Don't switch straight to 12/12 according to new study

[Pepe le skunk]

looked like i was in week 2 of flowering by the end of week one. The flowering spots were all over rather than just at the nodes themselves and had mature pistils rather than developing ones in the same amount of time. I'm just going by observation and that was the only change i made to my system which resulted in a larger yield with denser buds.

There is an interesting book by Tom Flowers called Marijuana flower forcing concerning the critical night length that would explain some of the results people are having. Critical night length is the exact number of hours strains need to start producing flowers and it is not the same for every variety. It is not always 12 hours of darkness to start flowering. Here is a quick guide to show the critical night length for different varieties. Hope that helps.

So an afghani only needs 11:30 of dark time to start flowering were a tropical sativa from thailand needs 12 hours and 40 minutes of darkness to really flower heavily. That is why with sativas when people cut the light hours to 10 hours on and 14 of darkness the plants start to flower heavily in the end to ripen. It is because they didn't give enough darkness to begin with for heavy flowering. They should or could have given it more dark and it might have finished faster. Also posted times for outdoors and locations so it might help some people if outdoors. You could try using light blockers to flower faster outdoors.

 

[Mad Hamish]

Ummm. Dropping your night time temps by more than 10 degrees causes stretch...and shit loads of it.

Great advice UB.

Careful he'll one star all your threads... UB Wuz Here.. LOL

 

[Situation420]

Ummm. Dropping your night time temps by more than 10 degrees causes stretch...and shit loads of it.

Great advice UB.

Yea I saw advice in someone else thread and have to agree too. He even said it himself that it causes cell elongation.

drop the temps from day to night at least 10F, preferable 20F. This way the plant will not use up too much of its resources, starches, to the process of respiration during the night when it's not making food for the plant. It will go more towards cell division/elongation.
UB

 

[Unequalibrium]

Ummm. Dropping your night time temps by more than 10 degrees causes stretch...and shit loads of it.

Great advice UB.

Baloney. The temps in my room are different depending what time of year, but there are times the temps have more than a 10 degree drop at night and they don't stretch any more than usual.

 

[Situation420]

Do you think it may have to do with species UB? Even Jorge Cervantes has said this before and I greatly respect his teaching because the are based on nearly 50 years of observation.

 

[Uncle Ben]

Ummm. Dropping your night time temps by more than 10 degrees causes stretch...and shit loads of it.

Great advice UB.

Thanks! It's about time you learned something.

If you can't deal with The Stretch, then you need to get out of the game. Stretching during the early flowering phase is normal, it's just what cannabis does.

Having said that, it's high P in relationship to N that causes stretch. IOW, you lamebrains addicted to bloom foods are not only fucking up your yields but you're adding salt to your wounds by using high P bloom foods. Here's the real science -

"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."

http://www.gpnmag.com/what-really-causes-stretch

Uncle Ben

 

[Uncle Ben]

in fact the research is all based on supposition ...invloving variables like starch, molecules T & S , day , night, & more.

plus they dont even mention temp, hormone activity, or anything related to flowering plants.

Exactly my point. Notice it was all about math calcs?

 

[smokinafatty]

I read the article again and they say the plant stops growing when it runs out of starches. It sounds like switching from 20/4 to 12/12 will make your plant stop growing for about 8 hours a day for a few days. I'm going to start tapering to 12/12, adjusting 15 minutes a day. The article also said they try to have an extra 5% of starches at the end of the night, which sounds like they can handle every night being 5% longer than the last. If your dark cycle is 6 hours, adjusting 15 minutes a day will stay within 5% (5% of 6 hours is 18 minutes). I'm assuming they can handle a change every night, but I have no real reason to think they can adjust that quickly.

It would take 32 days at the rate of 15 minutes a day, to switch from 20/4 to 12/12. (Well, my math is 20-12 = 8 * 4 [4 sets of 15 in an hour] = 32.)

 

[Uncle Ben]

So an afghani only needs 11:30 of dark time to start flowering were a tropical sativa from thailand needs 12 hours and 40 minutes of darkness to really flower heavily. That is why with sativas when people cut the light hours to 10 hours on and 14 of darkness the plants start to flower heavily in the end to ripen.

I'm not totally buying Tom Flowers chart or his "facts" regarding real sativas. I say 'real' because most haze has been adulterated with indica. That is not the original Haze which is a sativa hybrid - Acapulco Cold X Colombian Gold X (S. Indian X Thai). Based on my personal observation (and I've grown a lot of sativas) equatorial sativas are neutral day dicots, those located plus or minus say..... 15 degrees of the equator, and flower based on chrononlogical age as opposed to phytochrome accumulations in the leaf. Good example, I grew Dalat Vietnamese indoors and I tried all kinds of photoperiods to induce it to bloom, nothing worked, only age. Even a night of 15 hours and day of 9 didn't work. It only flowered when it had vegged for like 5 - 6 months and then the blooming was profuse. Zamal, a pure sativa from La Reunion was the same way.

UB

 

[Uncle Ben]

Yea I saw advice in someone else thread and have to agree too. He even said it himself that it causes cell elongation.

You misunderstood me and took what I wrote out of context. Cell division/elongation has nothing to do with internode lengths. Plants grow via cell division and elongation no matter what the plant unit is - roots, stems, leaves. What do you think causes a tree to increase its trunk girth? Dat right kiddies.......

https://www.rollitup.org/advanced-marijuana-cultivation/267989-uncle-bens-gardening-tweeks-pointers-80.html

UB

 

[Sir.Ganga]

Ummm. Dropping your night time temps by more than 10 degrees causes stretch...and shit loads of it.

Great advice UB.

My room stays a constant 72 degrees day and night. My plants have never been happier! Dropping your temps was once thought to be critical aspect of indoor growing but since been proven to be a myth. Considerable differences in temps at any time is not good for any plants, this is just common sense but having to drop the temp? BUNKIM...total myth...spend your money on humidity control because this is the main concern on any indoor grow when the lights go out!

 

[Uncle Ben]

My room stays a constant 72 degrees day and night. My plants have never been happier! Dropping your temps was once thought to be critical aspect of indoor growing but since been proven to be a myth. Considerable differences in temps at any time is not good for any plants, this is just common sense but having to drop the temp? BUNKIM...total myth...spend your money on humidity control because this is the main concern on any indoor grow when the lights go out!

More bullshit from you and a stupid practice that is against everything that's natural as it pertains to mother nature. You don't understand plant evolution or processes.

I don't do myths, I bust them. I also bust know-it-alls like you. From the U. of N.C., College of Ag and Life Sciences - http://www.ces.ncsu.edu/depts/hort/consumer/weather/tempeffect-plants.html

Thermoperiod refers to daily temperature change. Plants produce maximum growth when exposed to a day temperature that is about 10 to 15°F higher than the night temperature. This allows the plant to photosynthesize (build up) and respire (break down) during an optimum daytime temperature, and to curtail the rate of respiration during a cooler night. High temperatures cause increased respiration, sometimes above the rate of photosynthesis. This means that the products of photosynthesis are being used more rapidly than they are being produced. For growth to occur, photosynthesis must be greater than respiration.

Everyone should read this article and memorize it from top to bottom.

UB

 

[GandalfdaGreen]

More bullshit from you and a stupid practice that is against everything that's natural as it pertains to mother nature. IOW, you don't understand plant evolution or processes.

I don't do myths, I bust them.

UB

Uncle Buster. Sounds good to me.

 

[NietzscheKeen]

I'm not totally buying Tom Flowers chart or his "facts" regarding real sativas. I say 'real' because most haze has been adulterated with indica. That is not the original Haze which is a sativa hybrid - Acapulco Cold X Colombian Gold X (S. Indian X Thai). Based on my personal observation (and I've grown a lot of sativas) equatorial sativas are neutral day dicots, those located plus or minus say..... 15 degrees of the equator, and flower based on chrononlogical age as opposed to phytochrome accumulations in the leaf. Good example, I grew Dalat Vietnamese indoors and I tried all kinds of photoperiods to induce it to bloom, nothing worked, only age. Even a night of 15 hours and day of 9 didn't work. It only flowered when it had vegged for like 5 - 6 months and then the blooming was profuse. Zamal, a pure sativa from La Reunion was the same way.

UB

OMG, I've been trying to research this question for months and no one seems to have any real answers! Thank you Uncle Ben! I KNEW there had to be a day neutral variety out there since all I've tried have pretty much gone to flower as soon as they are planted outdoors and I've seen some nice sized plants grown closer to the equator than I am. I guess the problem is even "real" sativas, as you put it, have been adulterated by some Indica somewhere down the line. I will have to see if I can find those varieties you've mentioned. Thanks again.

Never had a plant not start to flower at 14 plus you get two more hours of light... I have experienced better results that way. Bigger yields and faster ripening at the end.

This has been my experience as well. Even though some argue that more darkness means better results.

 

[Uncle Ben]

OMG, I've been trying to research this question for months and no one seems to have any real answers! Thank you Uncle Ben! I KNEW there had to be a day neutral variety out there since all I've tried have pretty much gone to flower as soon as they are planted outdoors and I've seen some nice sized plants grown closer to the equator than I am. I guess the problem is even "real" sativas, as you put it, have been adulterated by some Indica somewhere down the line. I will have to see if I can find those varieties you've mentioned. Thanks again.

Welcome! Curious, where do you live and what do you prefer, pure sativa or the typical mutt? Not real clear what works best for you outdoors.

 

[Impman]

More bullshit from you and a stupid practice that is against everything that's natural as it pertains to mother nature. You don't understand plant evolution or processes.

I don't do myths, I bust them. I also bust know-it-alls like you. From the U. of N.C., College of Ag and Life Sciences - http://www.ces.ncsu.edu/depts/hort/consumer/weather/tempeffect-plants.html

Thermoperiod refers to daily temperature change. Plants produce maximum growth when exposed to a day temperature that is about 10 to 15°F higher than the night temperature. This allows the plant to photosynthesize (build up) and respire (break down) during an optimum daytime temperature, and to curtail the rate of respiration during a cooler night. High temperatures cause increased respiration, sometimes above the rate of photosynthesis. This means that the products of photosynthesis are being used more rapidly than they are being produced. For growth to occur, photosynthesis must be greater than respiration.

Everyone should read this article and memorize it from top to bottom.

UB

The PROPER terminology is Thermoperiodism. Thermoperiodism is critical for plants to develop properly, and it directly effects the length of your flowering, the density of the nugs and the over all health of the plant. Thermoperiodism is directly connected to the plants chronological clock. I completely fucked up and stuntd a grow last summer by trying to run my lights at night, but the summer was too hot. What happend was a slightly higher or equal day/ night temp. My plants NEVER finished and were stunted. I was running three 600 whps and a AC, so you can imagine how much my electric bill was. Thermoperiodism is so critical, I cant stress this enough. I bought a great tool at Radio Shack that gives you your day/night temperature... or it tells you what the temp was exactly 12 hours earlier.

 

[Impman]

Thermoperiodism should be in every Newbs vocabulary, but you cant even find it mentioned anywhere on RIU aside from my newb thread I started a few weeks ago. Plants do not remember anything at all, ever. You need to read about plant science. No where in Jorges book or that other deush Eds' is thermoperiodism mentioned, yet thermoperiodism, along with light cycle, directly affect the chronological clock. Plants remember NOTHING but I can control my plants flowering cyle with temperatures and lights. It is called photosynthesis plants have no brain whatsoever. This is the ultimate stoner thread. This is marijuana grow science epitamized, what a shame. If a real plant scientist resd the title of this thread he would be laughing till he pissed his pants. sad

 

[LadyZandra]

even at an abrupt 12/12 switch there isnt any flower(ing) hormone present.

that takes 7 to 14 days easy. & the plants are still in veg mode.

? plants aint people ?

fuck they're simple organisms. you supercrop them, you clone them. you toss them into flower.

however, i strongly agree that plants have "memory" & environment plays a HUGE roll.

inducing fall like weather into the schedule imo triggers the flip faster. not just the light cycle.

think bigger more connected variables.
since reducing the idea to a common denominator seems not so biological.

this concept of plant intelligence cant be proven in a human sense with human terms.

its cellular imo.
plants are storing data in their cells about temp, humidity, light, hormones, etc.

its when these triggers accumulate, the plant flips.

smoke em if u got em

Well said!!!

 

[legallyflying]

More bullshit from you and a stupid practice that is against everything that's natural as it pertains to mother nature. You don't understand plant evolution or processes.

I don't do myths, I bust them. I also bust know-it-alls like you. From the U. of N.C., College of Ag and Life Sciences - http://www.ces.ncsu.edu/depts/hort/consumer/weather/tempeffect-plants.html

Thermoperiod refers to daily temperature change. Plants produce maximum growth when exposed to a day temperature that is about 10 to 15°F higher than the night temperature. This allows the plant to photosynthesize (build up) and respire (break down) during an optimum daytime temperature, and to curtail the rate of respiration during a cooler night. High temperatures cause increased respiration, sometimes above the rate of photosynthesis. This means that the products of photosynthesis are being used more rapidly than they are being produced. For growth to occur, photosynthesis must be greater than respiration.

Everyone should read this article and memorize it from top to bottom.

UB

Wow that's news to me. Plants can photosynthesis at night!!!

Using temperature differencials to steer your plant is a well known fact. There are a slew of articles out there stating that minimizing temp diff is a good thing. Again, I'm not posting links, the info is out there. High differentials cause increased elongation. Period. High diffs an be used effectively to bolster sugar deposition in large bodied fruits like tomatoes but cannabis flowers don't have the thermal mass to take advantage of this phenom.

 

[NietzscheKeen]

Welcome! Curious, where do you live and what do you prefer, pure sativa or the typical mutt? Not real clear what works best for you outdoors.

I live at exactly 30 degrees lat and about 15 minutes from the Coast. I think I would prefer a pure sativa, but anything that would give me a decent veg period would be great! PM me if you need more details, lol. I don't really like sharing info on here.

Wow that's news to me. Plants can photosynthesis at night!!!

That's not what UB was saying. All he stated was there had to be more photosynthesis than respiration. You know... like calorie intake vs calories burned.