24 hrs

Also yes some people have shared success with a 36 hour dark period. They say the buds set 5 days earlier and increase bud sights(hmm?) but does not make buds finish faster.

Fease said:

So I can't flower with blue floros? It's the photo period First and foremost. Maybe outside red spectrum gives the plant an early hint. Blue light works too though indoors. Use logic.

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Oh, most certainly you can......I almost only run MH...a dark time will cause flower set.....
Far reds initiate flower set faster...

In nature...and in your garden...there is a 2 hour time period as the plant transitions (hormonally) to night....730nm LEDs make it almost instant...and give you (in theory) 2 more hrs of lights on time to grow with, even in flower..if sometime during the night. the plant gets flashed with 660nm or less.....it turns the "day time" hormones back on....and defeats the flowering hormones!

Dude, you will find as you grow that logic. Does not apply well to growing.

As far as your friends getting closer node set by an "extended" dark period....I don't believe it!
I have never seen it for myself in 40 years of growing and trust me,,,,I have tried.....While a dark period of extended time is said by some to get a faster to actual flower set....I have not seen a significant increase in any of these, and 5 days? I don't think so. The theory is that a 24 - 36 hr darkness before the flip will increase hormone build up to actually cause a faster flower set (the closer node set thing is someones logic).

In reality, The hormone build up will simply and quickly go right back to normal when light is applied. So any assumed benefit will go right out with that light....There is so much going on in the plant at the cellular level throughout the day that it is hard to explain without taking up more time then I want to, and more space then this site would allow.

Its like the popular theory that 24/0 in veg. makes a plant grow faster.....Maybe a bit but, The plant will grow better and stronger with at least a 4hr lights out time every day.....

Doc

Word.

My understanding of a few days of lights out before harvest was for the plant to use up stored starches to speed up the cure, also during the dark cycle the plant produces/repairs/replenishes trichomes, something to that effect. Certainly the trichomes seem taller/fuller with an extended dark cycle before chop, but I haven't measured anything or did a taste test for the curing/starches aspect either.

calicocalyx said:

My understanding of a few days of lights out before harvest was for the plant to use up stored starches to speed up the cure, also during the dark cycle the plant produces/repairs/replenishes trichomes, something to that effect. Certainly the trichomes seem taller/fuller with an extended dark cycle before chop, but I haven't measured anything or did a taste test for the curing/starches aspect either.

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Well,,,this thread was about a 24 - 36 hr lights out time at the flip to induce a faster flower, with closer node set....BUT, You are correct that the plant (in your good terms) produces/repairs/replenishes trichomes at night.
A few days of lights out before harvest is another "logic" myth. I would say that if you are one of the "long night" 6/18 or 8/16 people you might simply run your last night or 2 at 12/12 if you feel that tric recovery should look a bit better.


In an earlier post I said that Auxins make the plant stretch in early bloom......I forgot to add that this also due to Auxin working in tandem with Gibberellins. Gibberellin is also the hormone that is produced when the plant is stretching to light. Gibberellin makes it stretch and Auxin helps in several ways...thus it is actually a tandem effort....My Bad.

Doc

Someone else had touched on this earlier and said that lights out before harvest would increase potency, I just wanted to elaborate a bit. I think the plants look better but not necessarily be more potent, however with the starches being used this might also make it taste a little better, or at least be cured a little sooner. Good info doc.

v.s one said:

Does 24 - 48hrs of darkness before flowering speed up flowering and does 24 - 48 hrs of darkness increase resin production? If anyone has had success on this matter or think it's bull hollar. Peace RIU

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Before I flower my plants I put them in 36 hours of complete darkness. It def speeds up the flowerin process bcuz it triggers the change in hormones of the plants. It provides the switch from the veg to bloom stage and I find I can get flowering sites to set within 4-5 days opposed to 7-10 that kost see. Obv it is strain dependent but it does and will make a difference by activating the plants internal hormones (i forget the scientific name for them but it does switch the clock and will speed up flowering 100%).

Also at the end of bloom if you give complete darkness for 48-72 hours it will increase ripeness and residue content. I find both these methods to be extremely helpful to your grows and I always use both techniques for my gardens. Idk the exact scientific names for the techniques but I do know that it is documented and well practiced throughout the hobby and does provide beneficial responses for your grows. BOL & HAPPY HARVESTS

I'm going to start doing both also to speed up flowering and increase tric production

Dr. Who said:

Auxin

"Auxin plays also a minor role in the initiation of flowering and development of reproductive organs."

Taken from: Plant Hormones: Biosynthesis, Signal Transduction, Action

I knew I saw this somewhere.....wife dug it out....I did not want to say it till I could list the source...

Doc

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Your wife is a keeper!

Thanks for the info, great thread.

Dr. Who said:

Well,,,this thread was about a 24 - 36 hr lights out time at the flip to induce a faster flower, with closer node set....BUT, You are correct that the plant (in your good terms) produces/repairs/replenishes trichomes at night.
A few days of lights out before harvest is another "logic" myth. I would say that if you are one of the "long night" 6/18 or 8/16 people you might simply run your last night or 2 at 12/12 if you feel that tric recovery should look a bit better.


In an earlier post I said that Auxins make the plant stretch in early bloom......I forgot to add that this also due to Auxin working in tandem with Gibberellins. Gibberellin is also the hormone that is produced when the plant is stretching to light. Gibberellin makes it stretch and Auxin helps in several ways...thus it is actually a tandem effort....My Bad.

Doc

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i thought it was the switch to red spectrum light that caused the stretch? i was told the mh blue spec keeps closer node sets wile the red creates stretch, so using the mh bulb for the first 2 weeks of 12/12 will keep your plants from stretching...
also that if u were to use an hps in veg plants would be taller and thin..wile using mh in veg keeps your plants shorter and more stocky..

thanks again for the info doc,, sorry bout all the questions..

TheChemist77 said:

i thought it was the switch to red spectrum light that caused the stretch? i was told the mh blue spec keeps closer node sets wile the red creates stretch, so using the mh bulb for the first 2 weeks of 12/12 will keep your plants from stretching...
also that if u were to use an hps in veg plants would be taller and thin..wile using mh in veg keeps your plants shorter and more stocky..

thanks again for the info doc,, sorry bout all the questions..

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Absolutely I always run MH's for the first 2 weeks of bloom.. Not only are the plants still in a veg state for first week or so .. Using MH is one of industry kept secrets for reducing stretch during bloom and shortening internodal spacing. It really does work and is tried and true.

Dr. Who said:

Dude, you will find as you grow that logic. Does not apply well to growing.

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Ain't that the truth...

Thanks for that knowledge @Dr. Who

recent switch from mh/hps to ceramics..great gpw with cmh, better than hps or mh.. but stretch related to plants seeems more to do wth the difference in kelvins.. as a 6500k mh in veg to a 2100k hps in flower has lots of stretch, going from a 6500k mh to a 3100k cmh stretch is far less,,,or going from a 4200k cmh to 3100k cmh veg to flower = even less stretch...as stated above using mh in veg and first few weeks of flower stretch is minimized.. also for those of us who use one bulb for veg and flower weather its hps/mh/ or cmh the stretch is less than as with a switch in kelvin..so hps used from veg to finish will stretch,,,but less than the same plant that had mh in veg than hps in flower.or a plant that had only mh veg to finish will stretch less than a plant that used only hps or both.. i feel that i like some stretch but not alot.. the bigger the change in kelvin from veg to flower= the larger amount of stretch..