# 48hrs of darkness before harvest



## marcopolo

Hello, 
I’m days away from harvest and wondering if anyone has any feedback on 24-48hrs of darkness before harvest. I read this recommendation in a few growing books.


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## The Hemp Goddess

I really have never read this or done this.  

What is their rational for doing this?  Is there a scientific reason?


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## WeedHopper

Yes please enlighten me on the science behind that. I would like to know because im not understanding whats going to happen in that small amount of time with lights off that wouldnt happen better with lights on.


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## cardgenius

The theory goes, trichome production happens at night therefore putting it in 24-48 hours of darkness will give it a boost just before you harvest.


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## WeedHopper

Hummm,,,not sure about that. Seems that would happen better with lights on,,but im not a Botanist.
What i do know is the weaker the light the less Trichrome production,,so im not sure how Trichrome production would be better with a 48hr dark period.
I did a ton of reading on this and 95% of the growers said its total bull manure.


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## cardgenius

Bubbletrouble said:


> Hummm,,,not sure about that. Seems that would happen better with lights on,,but im not a Botanist.


Yeah, I think of it as a growers old wives tale/myth. Seems like there’s a lot of misinformation out there that goes unchecked and gets passed around easily.


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## The Hemp Goddess

Yeah...I'm thinking the "theory" is wrong, too.  This is the reason that I always want to see some kind of scientific reason behind these ideas.  If there is no logical/scientific reasoning behind something, I am surely going to question it.


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## Locked

Save yourself 2 wasted days and just harvest. Just an old wives tale.


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## WeedHopper

Now that was funny Hamster Lewis. True,,but funny.


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## 420trout

.


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## WoodsRat

I saw the same article a few years back, so I tired it. I couldn't honestly tell any difference between 48 hours of dark before harvest and normal harvest. I also tried the "nothing but water" flush while growing hydro. Absolutely no difference in taste or buzz.
The dark cycle would be an easy one to try if you wanted to. Harvest all most all of your plants, leave one or two, and turn off the lights. Go back in two days and finish the harvest. After they all cure, see if you can tell a difference. I couldn't.


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## stinkyattic

The rationale I've heard for this is a different version; that light destroys THC.
While it is true that uv radiation decomposes hydrocarbons of all sorts, it's not like you've got a crazy intense uv lamp in your grow room lol.
Dark cycle is just one more overcomplicated overhyped YouTube clickbait-hooey theory.


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## spaade

As I plant physiologist and biologist specializing in cannabis I can assure you that the "48 hour light depravation" prior to harvest is typical "street" mythology and Youtube bull. One aspect of trichome production in cannabis is protection against chromosomal mutation and DNA damage caused by UV light, particularly UVC by shading the surface area of the leaf and flower lessoning UVA, UVB and UVC light penetration. Therefore, more light equals more trichome production which equals more THCA and more ∆9-THC production at the cellular level within the trichome. 48 hour light deprivation would actually slow down trichome production hence slowing down THC production.
-spaade


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## WeedHopper

Exactly,,, good post Spaade.


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## Steve1

What I have heard has nothing to do with trichomes   I heard that by turning off the lights, your basically “turning off” the plant and some of the nutrients and chlorophyll in the plants settle to the roots. While that sounds reasonable, I think it would take a lot longer than 24-48 hrs.   I did it my first grow because I knew no better but I don’t do it anymore


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## The Hemp Goddess

I think basic biology tells us that chlorophyll is only in green parts of the plant and, therefore cannot settle to the roots.  I am assuming that other plant nutrients are not going to migrate anywhere either.


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## stinkyattic

Correct; and as chlorophyll breaks down, an actively growing plant will scavenge and redistribute the released nutrients through its vascular system to where it is actively trying to grow- its reproductive parts.
There's a reason the sugar leaves are the last to yellow on a severely malnourished plant approaching harvest. Those buds awaiting pollination are that plant's last hope to breed for the next season. 
You can't really game biology on this one; )


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## marcopolo

This was always a head scratcher, but now it’s clear to be an old wise tale. I read this is Jorge Cervantes growing bible and most of this literature is very useful, but the 48 of darkness allows floored me. 

Anyways, I didn’t do the 48 of darkness. Just harvested like normal. Looking good so far. Wet trimmed, and in the dark dry room at 68F and 55 humidity.


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## mp57

I would like to ask a question about creasing branches or drilling a hole in the trunk of plant to increase or boost resin production?


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## WeedHopper




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## oldfogey8

mp57 said:


> I would like to ask a question about creasing branches or drilling a hole in the trunk of plant to increase or boost resin production?


if by 'creasing branches' you mean supercropping, that is good for leveling your canopy height but i have never noticed an increase in bud size(which some people report) or resin production(which i have not heard of). drilling holes in the trunk? no. there is a lot of misinformation out there. don't fall for it. grow healthy plants and you will get nice yields and nice smoke/vapor/edibles. get a few grows under your belt before you start trying anything whacky...


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## Kyfarmerb

oldfogey8 said:


> if by 'creasing branches' you mean supercropping, that is good for leveling your canopy height but i have never noticed an increase in bud size(which some people report) or resin production(which i have not heard of). drilling holes in the trunk? no. there is a lot of misinformation out there. don't fall for it. grow healthy plants and you will get nice yields and nice smoke/vapor/edibles. get a few grows under your belt before you start trying anything whacky...


I second that, sure watch a few tutorials on super cropping Kyle kushman is my favorite teacher/instructor on said subject.but I would def not drill a hole in it.and as far as a 24-48 hr dark period before harvesting I don't do it.i have multiple times and I haven't multiple times and I have never seen a difference bro.just food for thought.yo,you can check my current grow journal here, it's called (Back in the saddle again) any and all questions are welcome.happy growing to ya bro.


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## Rosebud

mp57 said:


> I would like to ask a question about creasing branches or drilling a hole in the trunk of plant to increase or boost resin production?


NO, why would you think that would help? Oh, i know you heard stressing the plant makes better weed? Maybe but don't drill a hole in your plants, please.   When they talk about low or high stress training, that is not what they mean.


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## Cannagrammy

oldfogey8 said:


> drilling holes in the trunk?



I've done it a few times to see what I thought...


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## Rosebud

not the best thing to do. So you had already done it before you asked us? Apologize to the plant and see if it lives. Please tell me where you got this idea?


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## Cannagrammy

I, first off didn't ask.   I've been growing for awhile and I don't sit around and only read, I do experiments of my own to come to my own conclusions, I was just sharing the fact that I had already tried it.

You want me to apologize to my plant that was harvest like 4 years ago?   Lol, yeah, she isn't still living, I killed her on purpose.   Don't we all?

And the idea has been around for a long time.  I read about it, well, like 4 years ago.


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## WeedHopper

I can not see how drilling a hole threw your stalk is going to do anything but cause it problems with disease and bugs. Kinda like drilling a hole in a perfectly good pipe and pluging it to stop the leak.
I dont get it. If i drill a big hole in my Apple tree,,it might not kill it,,but it dang sure isnt going to help it grow fruit.


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## WeedHopper

mp57 said:


> I would like to ask a question about creasing branches or drilling a hole in the trunk of plant to increase or boost resin production?


Think this person ask the question.


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## Cannagrammy

The premise is to do it 7-10 days before harvest (like some do flushes) to stress it out before harvesting.  So, yeah,  not long enough to cause any problems.

I am the kind of person that if I see different opinions on something, well hell, I will just try it myself to come to my own conclusions.   It's fun and educational, I highly recommend it!


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## tastyness

oldfogey8 said:


> ... there is a lot of misinformation out there. don't fall for it. grow healthy plants and you will get nice yields and nice smoke/vapor/edibles. get a few grows under your belt before you start trying anything whacky...


WELL SAID and an excellent reminder @oldfogey8


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## ram40ut

Rosebud said:


> not the best thing to do. So you had already done it before you asked us? Apologize to the plant and see if it lives. Please tell me where you got this idea?



I’m afraid to ask some of you guys anything, you’re just too smart for some of us. I think I’d rather just let them die than bounce around to multiple boards trying to get answer without all the condescending retorts.

I’ve been going to various forum and message board communities for at least 20 years. Golf, college football and hoops, Cubs baseball, musical gear like guitars, mandolins, and fiddles, military scale modeling, and of course cannabis growing, and I must say, weed  growing forums are easily the rudest and most condescending.  I thought those snobs over at MandolinCafe were tough. They’re even worse than the fiddle nerds, but they can’t touch you guys. MP is not the worst but you guys are a carrier for sure.

Apologize to the plant, seriously?  I guess one must be very keen on becoming a good grower, and bring their A-game when they want to learn something.


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## WeedHopper

I just drilled a hole in my tomato plant,,poor sucker died very quickly. He took one for the team.

Dang Ram40ut,,thats a lot of forums Bro. I gets to high to remember that many passwords.
Might want to try the Misfits Thread. They will welcome you and probably give you a big hug. They are stoners for sure.


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## ram40ut

Bubbletrouble said:


> I just drilled a hole in my tomato plant,,poor sucker died very quickly. He took one for the team.
> 
> Dang Ram40ut,,thats a lot of forums Bro. I gets to high to remember that many passwords.
> Might want to try the Misfits Thread. They will welcome you and probably give you a big hug. They are stoners for sure.



I’m higher than a giraffes ass meself mate!


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## Steve1

I apologize to my plants when I whack them and hang them upside down !  LOL


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## Buzzy

Been there, done that.

48 hours of darkness prior to the chop is a waste of time.  Give your plants a once a week dose of flowering nutes in 12/12,  will do more for potency then wasting 48 hours.


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## ram40ut

Buzzy said:


> Been there, done that.
> 
> 48 hours of darkness prior to the chop is a waste of time.  Give your plants a once a week dose of flowering nutes in 12/12,  will do more for potency then wasting 48 hours.




I’m not sure I follow.   Are you saying give them nutes once a week during flower?


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## Buzzy

yes, water once a week,  also give nutes once a week.

I've had my best results following that simple approach.  A good 48 hours between giving the plants anything.  But I've used 5 and 7 gallon smart pots in the past. 

This run I'm using THREE gallon smart pots,  seems I gotta water or nute my plants every 36 hours, due to the smaller smart pots.


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## ram40ut

Buzzy said:


> yes, water once a week,  also give nutes once a week.
> 
> I've had my best results following that simple approach.  A good 48 hours between giving the plants anything.  But I've used 5 and 7 gallon smart pots in the past.
> 
> This run I'm using THREE gallon smart pots,  seems I gotta water or nute my plants every 36 hours, due to the smaller smart pots.




Cool, good stuff!


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## Steve1

Buzzy said:


> yes, water once a week,  also give nutes once a week.
> 
> I've had my best results following that simple approach.  A good 48 hours between giving the plants anything.  But I've used 5 and 7 gallon smart pots in the past.
> 
> This run I'm using THREE gallon smart pots,  seems I gotta water or nute my plants every 36 hours, due to the smaller smart pots.


I’ve always used 3 gallon pots and this grow I’m using smart pots. I’ve noticed I need to water them more.


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## WeedHopper

Same here. 3 gallon pots and i water or feed when the pots feel light and dry.
And yes im up early. Couldnt sleep,,besides im asleep by 9pm.


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## Buzzy

LOL< I turn my lights on at 4 AM daily!!!

Old skool forever, bro!


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## AladinSane

I have never tried the 48 hours of darkness as I could not get that concept to register in my 72 year old brain. Good to hear that I did not waste any drying time trying it. Thank you to those that tried it and reported their findings


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## Cannagrammy

ram40ut said:


> I’m afraid to ask some of you guys anything, you’re just too smart for some of us. I think I’d rather just let them die than bounce around to multiple boards trying to get answer without all the condescending retorts.
> 
> I’ve been going to various forum and message board communities for at least 20 years. Golf, college football and hoops, Cubs baseball, musical gear like guitars, mandolins, and fiddles, military scale modeling, and of course cannabis growing, and I must say, weed  growing forums are easily the rudest and most condescending.  I thought those snobs over at MandolinCafe were tough. They’re even worse than the fiddle nerds, but they can’t touch you guys. MP is not the worst but you guys are a carrier for sure.
> 
> Apologize to the plant, seriously?  I guess one must be very keen on becoming a good grower, and bring their A-game when they want to learn something.


Thank you.   It seems new members opinions aren't very highly regarded here, that's become extremely apparent.


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## Buzzy

I am new here and do not sense condenscending replies here.  There is actual moderation and restrictions in place here, which are needed.  There are bad cannabis forums on the internet,  this is about the kindest one I've seen.

You are judged by your knowledge and not "board seniority" it appears to me.  Exactly how it should be!


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## fellowsped

OMG people do you not understand a JOKE? Rosebud is a very nice person and a knowledgeable resource. She was giving a little bit of crap because this whole thing is a crack pot of an idea. Trying new things is good but there must be some sort of logical basis for what you're doing. Stressing a plant out is not going to make it more potent. If you can't understand "apologize to the plant" is a cheeky joke you're an oversensitive KAREN looking for something to be upset over. Glad I could help...


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## mp57

I grow my plants to big as I have problems with them becoming root bound in 7 gal. Of course I get at least 4 ounces from each plant. Due to my health I can no longer smoke, but I can eat the hell out of it. Made a batch of brownies and had the neighbors come over.  It was a good night!


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## tristanjohn42479

Buzzy said:


> LOL< I turn my lights on at 4 AM daily!!!
> 
> Old skool forever, bro!


Mine come on at 5 also and ofc at 11


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## Buzzy

I have two digital timers, STILL in their boxes!  I trust myself, MORE.


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## tristanjohn42479

It’s funny cause I have em on a timer and I still wake up at 445 on the dot get up open the flap for some air and the lights just kicking on its crazy ill doze off at night before 11 and something always bolts me awake at 11 to go close up the tent


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## Buzzy

Yeah, man.

The subconscious mind is powerful @ times!
:0


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## fellowsped

Good to know i'm not the only one who's mind wakes them up in order to open/close up the tent.


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## Eyeball Kid

The Hemp Goddess said:


> I really have never read this or done this.
> 
> What is their rational for doing this?  Is there a scientific reason?


I understand that the reason is to allow the plant to vacate nutrients from the leaves and buds. The nutrients and other chemicals can increase the likelihood that your harvested pot will taste bitter and be nasty on your throat. It looks like a variation on common advice to harvest outdoor plants JUST BEFORE DAWN. The nighttime darkness allows the plant to pull unpleasant tastes away from the buds.


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## Eyeball Kid

Cannagrammy said:


> I've done it a few times to see what I thought...


Looks like you’re stressing the plant with the hope that it will produce more trichomes in the buds. I’ve never done this, but it’s happened that branches will snap and will hang onto the trunk by a veritable thread. Now that’s stress! And you know what happens? NOTHING! Somehow, the branch still survives and even thrives, but I’ve never seen an observable difference in bud size or trichome production as compared to other areas of the plant.


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## Misanthropy Gardens

Eyeball Kid said:


> I understand that the reason is to allow the plant to vacate nutrients from the leaves and buds. The nutrients and other chemicals can increase the likelihood that your harvested pot will taste bitter and be nasty on your throat. It looks like a variation on common advice to harvest outdoor plants JUST BEFORE DAWN. The nighttime darkness allows the plant to pull unpleasant tastes away from the buds.



This was my understanding of the purpose for it. It seems to make some sense in that regard, that the plant would be pulling more nutrients from the soil during the time that light is shining on it and there may not be as much of it present in the upper parts during an extended time in darkness. There may be nothing to that at all for all I know, I never do it, mainly because my grows are usually a little staggered, but it makes sense on some level.
I have tried it a couple times years ago though and, honestly, I never noticed a difference.


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## spaade

Don't let oneself be caught up in all the street mythology and Youtube hype. There are many reasons for the production of trichomes. One of them being the shading of the bud to protect against UV light penetration causing chromosome damage on the cellular level. If you want to produce more trichomes give the plant more light. But...you need to start with good plant genetics that has the capability to produce a heavy coating of trichomes to begin with. If one starts with good genetics, good soil, good light of the proper color spectrum and intensity, water of proper pH, and supply the proper nutes, and good fresh air ventilation you will produce top level buds. Just make sure you provide what the plant requires...they know what to do with it...

spaade


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