# shut off lights completely in the last week of flowering??



## beeznutz (Mar 12, 2011)

somebody just mentioned that it's best to shut the lights off during the last week or so of flowering, right before harvest. anybody has any experience with this method?

you should still give them water during that time and i guess it'll boost the crystals/flavor.....


----------



## NorthernLights#5 (Mar 12, 2011)

depends on the strain.. what do you have?


----------



## tip top toker (Mar 12, 2011)

36 hours maybe, not a week. There have been some laboratory studies done on it, i think one said that it found a 30% odd increase in THC levels after the dark period, but i have never personally noticed much difference from one over the other when i've tried in the past.


----------



## beeznutz (Mar 12, 2011)

NorthernLights#5 said:


> depends on the strain.. what do you have?


how come?
i have super haze and purple kush right now...


----------



## MrDank007 (Mar 12, 2011)

There was a really good thread on this about a week ago i'm sure you can find in the search. Max was stated to be 72 hours.


----------



## beeznutz (Mar 12, 2011)

MrDank007 said:


> There was a really good thread on this about a week ago i'm sure you can find in the search. Max was stated to be 72 hours.


dont seem to find it, any idea what was the topic?


----------



## Honkeycorn (Mar 13, 2011)

beeznutz said:


> how come?
> i have super haze and purple kush right now...


Mmmmmm purple Kush.... 
View attachment 1491059


----------



## laboratory (Mar 13, 2011)

Are you discussing cold shock? 

When you take the plant and give it cold water, then put it in darkness for three days before chopping. 

Supposedly this makes it flower more and trich's increase but I tried it, and firmly raised the b/s flag. 

Soil was wet, plant took longer to dry, and just did not seem right.


----------



## DrFever (Mar 13, 2011)

i believe bricktop posted testing on this method i did it and its not to do this as mentiond above Supposedly this makes it flower more and trich's increase but I tried it, and firmly raised the b/s flag. 

Soil was wet, plant took longer to dry, and just did not seem right. 

pretty simple really just think when your in flowering you go to turn on your lights you sure can smell your plants right ???
thats because THC was being made lights off period 
now when you go to turn off your lights you notice wow that smell isnt really there thats because when light on period THC is vapourized burnt up in a sense lights off your plant will replenish all the thc that was lost during light cycle and will make more THC to account for the loses and so on as you flower does this make sense to you ????
i also read that if you decide to shut lights off prior to chopping you need to keep it off no more then 72 hrs an no less then 72 hrs 
so as brick top mentioned in some thread its 72hrs of total darkness keeping temps in the 60 degree for best THC percentage anymore you break done the THC and then it turns into another cant remember what it is called but i tryed it and was very impressed with the results and have implemented it


----------



## beeznutz (Mar 13, 2011)

DrFever said:


> i believe bricktop posted testing on this method i did it and its not to do this as mentiond above Supposedly this makes it flower more and trich's increase but I tried it, and firmly raised the b/s flag.
> 
> Soil was wet, plant took longer to dry, and just did not seem right.
> 
> ...


 that's my understanding as well.....what you've just explained makes sense when you think about it.
and it seems like most here say it should be no more then 72 hrs so that's good to know.
just shut everything down last night after realizing i had the lights on for 24hrs [my bad, forgot to switch the timer back on] so
it'll be off for the next 3 days then.
besides, nothing wrong with saving a bit of energy if you can


----------



## 420God (Mar 13, 2011)

It supposedly works better in the "White" strains.

"The Stichting Institute of Medical marijuana (SIMM), the first company to sell marijuana through the pharmacies of Holland, has been investigating the medical possibilities of cannabis, together with TNO laboratories and the University of Leiden.

One of their discoveries has been that to keep the ripe plants in the dark before harvesting could increase their potency.SIMM&#8217;s growers separated a crop of mature plants, harvested half of them and kept the other half in absolute darkness for 72 hours before cutting and drying. Analysis of the resulting dried buds showed that some varieties had seen an increase of THC of up to 30%, while CBD and CBN remained the same."


----------



## DrFever (Mar 13, 2011)

beeznutz said:


> that's my understanding as well.....what you've just explained makes sense when you think about it.
> and it seems like most here say it should be no more then 72 hrs so that's good to know.
> just shut everything down last night after realizing i had the lights on for 24hrs [my bad, forgot to switch the timer back on] so
> it'll be off for the next 3 days then.
> besides, nothing wrong with saving a bit of energy if you can


exactly i flushed week before i went 72 hrs off during last week plants uptake from soil was litterally nill i mean after 72 hrs my soil was still like a watered night before but in reality i am sure they took some but over all pots were wet


----------



## DrFever (Mar 13, 2011)

i think its always like last 2 weeks that its killer i mean you just want to end it but i find its the most crucial time off your complete grow thats deciding its time to harvest last 2 weeks is when weight / taste and everything else is there cut to soon you lose lose 
drying / cureing all these is what counts 
fck all to grow weed but keeping it alive giving them what they need last 30 days of flower is what counts 
you work so hard tending them would be a waste not to get full potential from your grow


----------



## Drake S (Mar 14, 2011)

I read Bricktop's post quoting the SIMM study and figured WTH? Why Not - sounded like no harm would be done with letting it rest the 72 hours and potentially increase the THC content. Guess it was one of those "no harm no foul" things to do for my first harvest ....


----------



## sloppyseconds (Sep 1, 2014)

Lights off for 2 weeks before harvest, go to the Attitude Seed Banks site and read Dinafem Seeds White Widow description!


----------



## Clown Baby (Sep 1, 2014)

lights off for two weeks before harvest..... come on people... really? They're your plants, and you're free to do what you'd like. But have you heard of people doing this for ANY other commercial vegetable or crop?


----------



## FRICKITYFRICKTYFRESH (Sep 1, 2014)

Yea 2 weeks seems a bit extreme. I'm growing Nirvana's white castle right now ( White widow x Ice ). Supposedly works better with white strains. I Might just cut my lights down to 6 hours the last week.


----------



## Mr Roboto (Sep 1, 2014)

pm or mold can develop in those few days of darkness also if the rh is high


----------



## Glaucoma (Sep 1, 2014)

I've always hated this theory.

Pro-dark camp: "It makes the plant grow a bunch of new trichs, increasing potency"
Me: "So all these 'new' trichs are mature/milky?"
Pro-dark camp: "I'm a unicorn!"


----------



## sloppyseconds (Sep 2, 2014)

Im in a week so far,complete darkness and i am noticing a stronger aroma than normal!!! No mold,but i am using the phresh hyper fan for exhaust!Its worth a try i guess, i started in the begining of week 8, also with a white strain from Nirvana called Bubblelicious!


----------



## Topo (Sep 4, 2014)

Hmmm. I had no noticeable difference in my last crop. Two plants were white strains, the other two were not. I'm not sold.

But I'm going to try it again. Tomorrow!


----------



## Jimdamick (Sep 4, 2014)

A lot of seed companies recommend increasing the dark period during the last week or so to increase resin production. What I do is at about 2 weeks before harvest, I reduce the on time by 1 hour, then every 2nd day reduce by 1 hour, ending up with 1 hour on time during the final 2 or 3 days. This mimics the reduction of sunlight that occurs in the fall, making the plant do its most to create more resin before the end of it's life cycle. It makes sense to me, but It is hard to tell if it really makes a difference.


----------



## sloppyseconds (Sep 5, 2014)

Well heres an update,1st day 0f second week i started seeing a little mold so conclusion keep the humidity low so i did one week in darkness and changed back to 12 hours i did a through manicure to get mold off and it seems to be going fine now!!!So watch humidity!!!Not really seeing a major difference its probly better to switch to uv the last week rather than darkness! I dont know, try it and draw your own conclusion............i should change my name to sloppyharvest lol!


----------



## hyroot (Sep 5, 2014)

this is so stupid. Does the sun turn off for a week. No. The sun schedule gradually drops to 14/10 over fall and late summer. On south America its 12/12 year round and eventually drops to 11/13. Same for Hawaii. If you want to play with schedules. Add 730nm infrared for 5 min at lights out. To more mimic sunset / nature. Use some common sense. Educate yourself before fucking up your grow. Gradually dropping light just makes the plants finish faster, stretch more and makes yield suffer.


----------



## Topo (Sep 6, 2014)

hyroot said:


> this is so stupid. Does the sun turn off for a week. No. The sun schedule gradually drops to 14/10 over fall and late summer. On south America its 12/12 year round and eventually drops to 11/13. Same for Hawaii. If you want to play with schedules. Add 730nm infrared for 5 min at lights out. To more mimic sunset / nature. Use some common sense. Educate yourself before fucking up your grow. Gradually dropping light just makes the plants finish faster, stretch more and makes yield suffer.


Solid points right there folks!


----------



## PetFlora (Sep 6, 2014)

We're all looking for the magic bullet edge

Many times it doesn't exist

I have tried ~ 3 days. Can't say I noticed anything


----------



## BDOGKush (Sep 6, 2014)

"One question I have been 
asked repeatedly by medical marijuana growers is when to harvest in relation to the light cycle. Many growers want to know if harvesting during the light cycle versus the dark cycle makes any difference in the potency of the cannabinoids. There have been many opinions on this subject and also many perpetuated myths. I decided to experiment with harvesting at different periods throughout the light cycle to see if there was a noticeable (measurable) difference in cannabinoid potency.

I decided to harvest three identical plants, all grown in the same room, at different times throughout the room’s light cycle. The first plant was harvested right before the light cycle occurred. The second was harvested right after the light cycle finished. The final plant was moved to a completely dark, temperature and humidity controlled room where it sat for 48 hours and was then harvested.

There was no noticeable difference in cannabinoid potency. We tested three samples from each plant and averaged the results of each plant to compare to one another. The results were virtually identical. There was no difference in potency in relation to the time at which the plants were harvested. Since machines are not always accurate, we also provided a few patients with blind samples to see if they noticed any differences in the samples. No differences were noted.

It is true that resin production on a medical marijuana plant peaks during the dark cycle. Because of this fact, there has been a myth perpetuated that cannabis harvested right before the light cycle begins — or cannabis given 24-72 hours of dark before harvesting — will produce a higher potency medicine than medical cannabis harvested during the light cycle. The problem with this theory is that a typical medical marijuana plant has a blooming period of about 50-60 days. When the overall time of the blooming cycle is taken into consideration, an additional day or two is pretty insignificant. The essential oils and resins are not produced overnight but instead are steadily built up over the entire blooming process. The number of cannabinoids degraded in one light cycle is completely negligible when comparing potency of the final product.

I tend to harvest my medical marijuana plants right before the light cycle begins, but this has always been a matter of convenience over anything else. It allows me to harvest and remove one crop and then bring in the next crop right at the beginning of the light cycle. This gives my next crop twelve hours under the blooming lights to better establish themselves before their flowering period begins (12 hours of darkness). My plants seem to transition better from vegetative to blooming if I start with the light cycle instead of immediately placing them in the dark cycle.

Harvesting during the light or dark cycle should be determined by personal preference and convenience. Growers should not get hung up on harvesting at a particular time in the light cycle. Plants harvested when they are ripe will be potent regardless of the time of day they are cut down."

http://bigbudsmag.com/grow/how/article/marijuana-harvest-myth-debunked-may-2012


----------



## hyroot (Sep 6, 2014)

light degrades trichomes. Whens its dark. Trichs replenish sort of speak. The calyx swell when the light doesn't come back on. It knows its life is over. Oils increase too anyway the plant is trying to push out seeds to live on its lineage. No pollination happens so the calyx swell. Oils increase. Imo no more than 24 hours of darkness. The plant will die and start drying after that. Then its a bitch to trim. in perpetual gardens. This is more difficult. harvesting qt peak ripeness is important.


----------



## sloppyseconds (Sep 7, 2014)

Next im gonna try 12 on a day, off next, on next day, off next day and so on and so on starting from first day of flower!!!Might save power, might just double my flowering time!!..... or maybe become another SloppyHarvest LMAO!!!!


----------



## Topo (Sep 7, 2014)

It's been 32 hours for my Cherry OG and Blueberry. Chop time in 4 hours. We'll see if the darkness period did anything.


----------



## churchhaze (Sep 7, 2014)

The main reason to leave the lights out for a long period is to allow the plant to burn off all the starch stored in the leaves during the night. Also, the plants "sap" is stored in the roots at night, so it's best to cut before the sap rises.

Leaves in general (for all plants except for starch-excess mutants) store just enough starch in the chloroplasts to last for one night's growth. 

The plant knows how long the night will be, and converts starch to sugars for immediate growth at a constant rate throughout the night. This means that after 12 hours of darkness, the leaves' chloroplasts are almost entirely depleted of starch, and growth stops.

*Iodine starch tests prove this*. After a period of light, leaves will stain black with iodine, but after a period of dark, they will not stain black with iodine.

Less starch in the leaves when harvesting should theoretically mean a more effective cure.

However... after 12 hours of darkness, the leaves have already converted all the starch to sugars and burned, and growth is stopped, so you may as well cut at this point.


----------

