Veg to Flower different transition techniques.

I do drain to waiste soil
topped once a week befor the slow flip
veg for 6 weeks from clone
1500ppm co2
Nute ppm 400-450 veg
flower. Ppm 500-700( depends on my run off ppm)
15 gal pots
2 weeks in 1 gal pots
2 weeks in 5 gals
2 weeks in 15 gals then flip
i also main line
veg water sched every 3 days
Flower every 2 days
4 gals of nute water each
straight water once a week
6.5 ph for the full cycle until later bud down to 6.2
strain BC seed kings "PURPS"

I read in the grow bible that growers do an extra long dark period just before switching to 12/12 like 18-36 hours of darkness. Has anyone actually implemented this?

Bump

I'm doing 24 hr dark before 12-12, several foliar sprays of this n that while they are resting.

Figure that will give them a quick boost for stretch / transition phase.

Extended dark periods (24-48 hours darkness) have been shown to induce flowering faster.

Basically lights main effect is storing energy in the leaves. During dark the plant is building itself up. So as long as your leaves arent light green 48 hour dark before 12/12 is perfectly fine

Oh brother.

When I started the guy who got me going does 5 days dark...yep 5. It has served him for 20+ years. That was the only odd technique he shared so I too asked the masses here a couple years ago. The general consensus was that anything over 24hrs is probably wasted effort. I did do a side-by-side with 3 days dark vs. flip immediate and there DID seem to be an advantage in bud starting with the dark ones. Was always going to do a more controlled test but just never have. I now just do 24hrs of dark or so. Doesn't kill'em...but neither does 3 or 5.

Blackout the greenhouse? I was skeptical of this when I went by a neighbor's and he had his greenhouse covered with black plastic. He does this every year, covers it up for four days, uncovering so that light was 12/12. That was about ten days ago and today I went over and he told me to come look ar his buds. My plants in my greenhouse, unmolested are just showing some white hairs and mapping out the colas. His have real buds, a month ahead of time. I told him I thought they would revert back to veg once back to about ten hours of sun. We shall see about that. Does anyone else do this? Opinions? Have to admit those plants, buds are amazing. It sure would help with the cold coming soon to have the plants finish in September. John

I meant to say, revert back to 14 hours, not ten.

Since plants burn off all stored starches within 24 hours, it seems counterproductive to use more than 24 hours dark. There's not a huge difference anyway, from going directly to 12/12. It just takes about 2-3 days for flower inductions to start taking effect if the plants had been in long days immediately prior. It's the long hours of light that produce the inhibitory effect, rather than the short nights. Anything over about 10 hours of light straight will do that. I don't know for sure if it's the same with Cannabis. If so, then 1 or even 2 long nights won't produce any flowering effect at all, somebody could test that to see it's true. If not, then I guess you wouldn't need an extra-long dark period to hasten flowering at all.

Here's a pdf about flower induction in another short day plant, beans. I assume the effect is similar for most short day plants. I've read the same type of thing in other articles about other plants. In this article they show the effects of long days interspersed with short days, but it gives you the general idea about the inhibitory effect. The other articles were about long days before the start of flowering though, I just don't have links for them or remember their names right now so this will have to do. Basically they found that the first couple inductive cycles had no effect when going directly from long days to short.

An interesting thing in that article is where it shows that they got as much or more budding (of beans) from a cycle of 8 hours light, 40 hours dark (treatment # 25 in Table 1) as from two days of 12.75/11.25 cycles (treatment 8.). So if that works with Cannabis, you would only be using 8 hours of light in 2 days, or 4 hours a day. Now, I don't think an 8 hour light period would be enough for Cannabis, but what about 12/36? Would that turn out the same as 12/12/12/12 with half the hours of light?

I don't have enough space or plants for testing stuff out like that, but maybe someone reading this does. Could turn out to have sacrificed a plant for nothing, if it grows really poorly. What I said about starch being burned off in 24 hours was regarding plants grown in normal photoperiods before the 24 hours. Plants adjust their rate of starch burning based on how long the night is expected to be. Though a plant's internal "clock" is based on a 24 hour day, maybe it can adjust to a 48 hour day after a few cycles. I would still expect some reduction in yield, but how much is the question.

Third day- I am using two contractor bags per plant,55 Gallon, 2 mil. With a wooden stick next to plant/ pot. I cover at 6:15 along with dinner chores, to real dark.I swear I saw the buds getting thicker a little this morning.

BobCajun said:

If so, then 1 or even 2 long nights won't produce any flowering effect at all, somebody could test that to see it's true. If not, then I guess you wouldn't need an extra-long dark period to hasten flowering at all.

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Hey Bob, many moons ago I went about testing various flower inducing photo/darkness phases. What I found, and keep in mind this is universal (at least, amongst hundreds of strains I've tested), is that the plants react favorably to 24 hours of dark pre-12/12. There is, indeed, physical expression of the onset of flower. You will see yellowing at each of the bud sites. This is due to the plant utilizing local nutrients as the "catalyst" to flower development. Anything beyond the initial 24 is a detriment as the deficit in nutrients/photosynthesis slows flower development. So, 24 hours of dark is the "point of diminishing returns". Testing took place over the course of ~5 years, been on 24 hours pre-12/12 for ~10 years. Before that, I hovered between 48-72 hours.

I noticed that someone mentioned a foliar feed during the initial 24 (recently, this thread, or another). Very close to what I do. I hit them before lights out, then again with a "light friendly" feed when the lights first come on. Almost no yellowing at bud sites, which means they do not exhaust the available nutrients. Yellowing is also gone after the first lights on foliar. You will notice a difference in initial flower development and overall flowering time.

You're welcome.

jellero said:

Blackout the greenhouse? I was skeptical of this when I went by a neighbor's and he had his greenhouse covered with black plastic. He does this every year, covers it up for four days, uncovering so that light was 12/12. That was about ten days ago and today I went over and he told me to come look ar his buds. My plants in my greenhouse, unmolested are just showing some white hairs and mapping out the colas. His have real buds, a month ahead of time. I told him I thought they would revert back to veg once back to about ten hours of sun. We shall see about that. Does anyone else do this? Opinions? Have to admit those plants, buds are amazing. It sure would help with the cold coming soon to have the plants finish in September. John

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Yeah, right!

How fun, extended darkness myth reproduction......A whole new heard of believers in transitional darkness myth are being born...

Any body see anything about such claptrap in their Nelson's greenhouse guide? No? I wonder why ??

If this was true, wouldn't there be notification of such in available printed material?

How interesting. I found in a paper in the publication of the AMERICAN SOCIETY OF PLANT BIOLOGISTS that extended no light times may actually cause more expressed stretch.

Here's something interesting - same paper:

shows that leaf production that is orchestrated by the SAM was unaffected, while internode length, which is regulated by the RM/RZ, was altered by overexpression of PHYA.

It basically states that some proteins and RNA's are over expressed and some Hormones are under expressed but, stored and released in bulk causing some increased nodal length expression.

Lets keep looking for more info.

An observation of less working stroma cells produced in the early "burst" of growth when light is reintroduced after extended non lighting times. Something like a reduction around 8-14%.

The conclusion actually indicates that the poster on page 1, who reduces his lights on time by an hr a day may actually keep the plant photosynthesizing at around 10% more after transition - then those of us who reduce all at once and more so over those who do an extended lights out time! Interesting...

Ok I spent enough time on this subject, researching papers.

My conclusion is still that extended lights out times for transitioning to bloom is not effective to reduce bloom times or reduce the stretch.
I did, in fact, find some evidence that slowing the transition will do these proposed ideals! I should say that the days used to slowly reduce will most likely be taking up the bulk of any time reduction. There should be some but, 10% is not likely. I am more interested in the reduction of the stretch as being an actual result.

Damn, now I have something else to try when I get back to my runs.....

@RM3 - take a peak at this post - found something interesting!
I searched for "Plants Impaired in State Transition" as a basic paper search.

Dr. Who said:

@RM3 - take a peak at this post - found something interesting!
I searched for "Plants Impaired in State Transition" as a basic paper search.

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Will do, thanks for the heads up.

I use Gas Light to veg as it actually does reduce stretch and finish faster

Current research supports a prolonged period of darkness pre-12/12. Manipulation of photoperiod responses by inhibiting phytochrome reactions (through prolonged darkness) in turn inhibits ELF3. This promotes early flowering, stem elongation, and increases yield.

Not going to go into detail, this happens by upsetting the plants circadian rhythms which are governed by the light cycle. "Evening Complex", ELF3 combining ELF4 and LUX, PIF4 and PIF5.

Also, Long Days vs Short Days and High intensity vs Low prior to flowering; Long Days at High intensity shorten the onset of flowering and the time between onset and maturity. So, shortening the "Lights On" period gradually to acclimate the plant(s) has a detrimental effect, not beneficial.


"Google" it, there is plenty of info out there if you use the terminology.

Went by my neighbors yesterday and the buds were well over an inch in diameter and long. I have no idea what is going on but it is hard to believe a switching then for four days would do this. I grow from seed, he buys clones. My greenhouse is open, lots of light with clear plastic, his is crowded, just some old fiberglass panels, no air flow and I noticed a bunch of fungus flies. maybe my plants are just behind?

jellero said:

Blackout the greenhouse? I was skeptical of this when I went by a neighbor's and he had his greenhouse covered with black plastic. He does this every year, covers it up for four days, uncovering so that light was 12/12. That was about ten days ago and today I went over and he told me to come look ar his buds. My plants in my greenhouse, unmolested are just showing some white hairs and mapping out the colas. His have real buds, a month ahead of time. I told him I thought they would revert back to veg once back to about ten hours of sun. We shall see about that. Does anyone else do this? Opinions? Have to admit those plants, buds are amazing. It sure would help with the cold coming soon to have the plants finish in September. John

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Dr. Who said:

Yeah, right!

Click to expand...

And then there is this response?! Do you have any green house experience. No question mark, it is not a question, it's clear that the answer is "No, none what so ever".


Here's why I say that;

"Photoperiod manipulation can be achieved in the greenhouse with relative ease. When the day length is long but a short day photoperiod is desired, blackcloth fabric may be pulled over plants in the evening and opened in the morning to provide plants with a short day. This is the same technique used in fall mum production to promote earlier flowering of chrysanthemum when days are naturally long. Growers may utilize existing blackout systems used in fall mum production to provide short days for other crops."



Link- http://msue.anr.msu.edu/news/light_and_flowering_of_bedding_plants



This is why there it is so difficult for new growers to get started on the right foot, too many people chiming in that don't really know what they are doing, or even why they do it. The answers provided should consist of "I have umpteen years of experience, all of my testing concludes this, and ALL of the peer reviewed science available supports my findings". Then we could all be on the same page, instead of spinning wheels.

I recently started manipulating light cycles before the flip to increase bud size slightly. I read about this in skunk magazine & had to try it in my perpetual. Many times I have to wait until there's space in the bloom room because there are plants that need more time to ripen so I have an extra grow tent I use for transitioning to bloom phase not only to shorten time in the bloom area but also to increase total yields. The simple trick is to lower the hours of light by gradually increasing dark by one hour or more in the weeks before flipping to bloom phase. I veg at 18/6 as normal from seed or clone until the plants are almost to size I want to flip em at. Then they go in the transition tent set to 17/7 for at least a week maybe 2 or even longer depending upon space availability. Each week I can either decide to place them in bloom or keep reducing the hours of light by one hour a week. This promotes very tight nodal stacking which results in slightly larger buds once they fill in. I used to just flip to 12/12 from 18/6 which makes some strains stretch out until there are lanky bare spots in between the nodes. The more gradual transition mimics the Suns natural cycle towards mid to late summer which results in slightly larger flowers. Try it it works though maybe not so easily in a greenhouse as it in indoors.

Just ran into my neighbor down at the river and talked about this gh blackout. Now he tells me it is 20 days, not 4... And in mid June to start with the blackouts. That makes a lot more sense but too late for this year. J