Need Advise On The Truth Behind the 24, 48, 72 Hours Of Darkness Before Harvest.

okay! i have been going straight mad these past few weeks getting everything completely ready for an optimal harvest. i wanted to get some info on the truths and myths behind the pure darkness thing before harvesting. i hear 24 hours, i hear 48 hours is awesome, and i hear about 72 hours being even better. but sometimes i hear things about 72 hours being not needed. i heard 48 hours of pure darkness is perfect before a harvest. this is my first grow. first of many as i am completely hooked. this si something i did when i was 17 many years ago and i am finally doing it. i will be doing some experimentations in the future, but for this harvest i need some input on which method is best. i have also been running into people who like to post "just because" kind of answers. i will not listen to those posts. nor will i even attempt anything anyone "just says". there is sooooo much misguided information on this forum. believe it or not, its true. i hear new shit every day, like today i heard a fellow community member tell me not to flush before harvest. WTF?! confused the hell out of me. so before i go and just chop down my hard work prematurely or just to chop, i want to know what method works best. i have heard many different things. please, if you want to help me, explain to me why it needs to be done. if you do not know, that is cool. i just will not be doing anything on a single one sentence explanation or a sentence less then 5 words. my mind can not process such little information. thanks in advance for anyone who has the time to help me. +rep for smart resourceful answers.

Ive read that if you do 24-48 hours of darkness before harvest, the plant thinks winter has come, and will start to use all its nutes up to try and survive.
So i guess it make sense.
72 hours seems too long to me, and there are people that dont flush before harvest, they say it makes no difference,

But im with you, im new to all this, I just like to play around, see what works for me and what doesnt.

happy growing.

Info from some of the books I read is if you give your plants total darkness for 48 hours just before harvest that more resin develops on buds. I did try this last harvest and I can't really tell you if it is true or not. But I didn't hurt anything. It was a good harvest, dense buds.. So I'll probably do it again next harvest. I grow in soil and stop watering 1-2 days before total darkness. I believe if you are growing in hydro or live in a high humidity area you should defiantly not go more then 24-48 hours of darkness. I think your chance of mold might increase.

ok... thank you!!

now whats up with this whole "not flushing" deal??

Some people feel if you don't flush, with a proper dry and cure job you can't tell the difference. Personally I can't, folks around here don't know either way.

Not flushing doesn't make a hole lot of sense to me.... maybe its how they interpret the meaning of flushing. Every book I've read and do personally is, irrigate with plain water to remove residual fertilizers in foliage and soil the last 7-14 days before harvest. I make sure to let 10-20 percent of the water drain out the bottom of the containers. I don't flush in the sense of over watering and drowning the plant. So flushing a plant because you over fertilized and flushing before harvest is two different things....

Assuming their are many hundreds of thousands, perhaps millions of trichomes in various stages of maturity on a ripe plant that is ready
to be harvested. Also assuming trichomes do not fully form, develope, and mature in as short a time as 72 hours,
what type of extra resin production will you get with more than 12 hours of uninterrupted darkness, as opposed
to doing a "normal" harvest.
No offense, but I don't care if someones friends brothers mom does it, and it works. I'm looking for a more fact based answer.

oHsiN666 said:

ok... thank you!!

now whats up with this whole "not flushing" deal??

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Flushing in soil is detrimental to the plant. It should only be used in a last case, emergency situation, when you've exhausted all other options. It is like getting your stomach pumped, your only gonna do it if you absolutely have to. The last week of flowering I like to feed once with molasses and then straight water. There is a difference between just water feeding and flushing.

The concept of an extended dark period has to do with why the plant produces buds in the first place. With the reduction of light to 12 hours of darkness the plant feels a change in season from summer to fall, it senses winter is coming. The plant forms sticky, dank, buds in order to catch male pollen. Now, as the saying goes... when you put that plant in the dark for 24 hours it is thinking "whoa, winter is here" and in a last ditch effort to get pollenated it will excrete more resin. I have done this as well and I am not sure if it works or not, I personally don't see the harm in doing so. Currently I can't do it because I have multiple plants that are harvested at different times. Another thing I like to do is during the last week of flowering is turn the lights to 14 hours of darkness. (just something I like to do).

Brick top had a really good post about this topic. With university studies about 72 hrs of darkness. Try and find it. I personally do it. It doesn't cost anything to not run the lights for 3 days. From what I read in his post i was convinced.

DO the 48 hrs darkness. It fools the plant into thinking winter is coming and it uses up all the last of its nutes to try and survive. this causes an increase in resin production. i've done it for 24hrs, 48hrs, 72 hrs of darkness and ive done 0 hrs of darkness (just chopped when ready).

from my experience the longer you can keep them in the dark; the better. i wouldnt go past 72hrs though.

some strains STATE IN THE DESCRIPTION that its best to leave the plants in darkenss for the last week or few days to get the most resin out of the plant.

i say 48-72 hrs is best.

it can't hurt your plant so theres only a potential for a positive result.


Also...

please..DO FLUSH...don't listen to any moron saying its not necessary. if you've ever taken a sample of your bud before the chop/flush you will notice that it burns black generally (the ash...the whiter the ash the more pure the contents being burned are...the darker/more black indicates that theres left over fertilizer/nutes in ur bud). also the taste is ruined and often times the smell suffers as well.

ive only cut down ONE plant prior to a flush because it was an emergency and i had to use it to make hash as the bud was harsh due to it not being flushed.

the ONLY INSTANCE where i can at least see/justify NOT flushing is if you feed 100% organic (soil, nutes, etc). even then i dont think a flush a few days prior to harvest would hurt.

theres much more of an upside to flushing than NOT flushing. it could ruin your bud and you dont want to be smoking chemicals from the nutes do you?

Does flushing hold true for all fruits and vegetables, or just marijuana?

themanwiththeplan said:

Also...

please..DO FLUSH...don't listen to any moron saying its not necessary. if you've ever taken a sample of your bud before the chop/flush you will notice that it burns black generally (the ash...the whiter the ash the more pure the contents being burned are...the darker/more black indicates that theres left over fertilizer/nutes in ur bud). also the taste is ruined and often times the smell suffers as well.

ive only cut down ONE plant prior to a flush because it was an emergency and i had to use it to make hash as the bud was harsh due to it not being flushed.

the ONLY INSTANCE where i can at least see/justify NOT flushing is if you feed 100% organic (soil, nutes, etc). even then i dont think a flush a few days prior to harvest would hurt.

theres much more of an upside to flushing than NOT flushing. it could ruin your bud and you dont want to be smoking chemicals from the nutes do you?

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I would not listen to this guy bout the flushing, search RIU and you will find posts by some very very reputable growers who tell you not to flush. Like I stated before, there IS a difference between flushing and just giving the plant water. When you flush you are putting the plant through A LOT of unwanted stress right before you harvest. I lay off on nutrients for the last 7-10 days of flowering so the plant doesn't have a "nutrient taste". If you feed the plants nutrients until the day you harvest perhaps yes, you will taste nutrients like you did. But I repeat, don't put the plant through unwanted stress. Just feed the plant water, the large fan leaves will turn yellow and begin falling off, and you will have excellent tasting bud with zero nutrient taste. Don't just take my word for it, research it for yourself. I'll save you some time, click on the link and go to the first post by riddleme.

https://www.rollitup.org/general-marijuana-growing/409622-truth-about-flushing-10.html

the plant will not be stressed if you flush correctly. i always give 3x's the amount of water as there is soil...so if im growing in 5gal pots i flush with 15gal of water . if its 3 gal pots i flush with 9 gal of water.

the plant wont get stressed as long as you dont pour all the bottles in one after the other...give those roots a chance to breathe inbetween.

ive done this for 3-4 years with no bad results or stressed out plants.

themanwiththeplan said:

the plant will not be stressed if you flush correctly. i always give 3x's the amount of water as there is soil...so if im growing in 5gal pots i flush with 15gal of water . if its 3 gal pots i flush with 9 gal of water.

the plant wont get stressed as long as you dont pour all the bottles in one after the other...give those roots a chance to breathe inbetween.

ive done this for 3-4 years with no bad results or stressed out plants.

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holy water bill. i just give them straight water towards the end. Sometimes add molasses.

themanwiththeplan said:

the plant will not be stressed if you flush correctly. i always give 3x's the amount of water as there is soil...so if im growing in 5gal pots i flush with 15gal of water . if its 3 gal pots i flush with 9 gal of water.

the plant wont get stressed as long as you dont pour all the bottles in one after the other...give those roots a chance to breathe inbetween.



ive done this for 3-4 years with no bad results or stressed out plants.

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I'm sorry but this is absolutely not necessary nor is it beneficial to the plant. Flushing with 3x the amount of soil is only to be used in a last ditch effort to remove unwanted nutrients from over fertilization or improper PH. When you don't give the plant nutrients for the last 7-10 days it naturally removes those nutrients. My smoke always burns white/grey ash which means there are no organic/non-organic compounds in the herb. I suggest you try it rather than flushing 15 gallons of water through every plant. Very reputable growers also say the same thing about flushing. Read the link I posted.

smokebros said:

I would not listen to this guy bout the flushing, search RIU and you will find posts by some very very reputable growers who tell you not to flush. Like I stated before, there is a difference between flushing and just giving the plant water. When you flush you are putting the plant through A LOT of unwanted stress right before you harvest. I lay off on nutrients for the last 7-14 days of flowering so the plant doesn't have a "nutrient taste". If you feed the plants nutrients until the day you harvest perhaps yes, you will taste nutrients like you did. But I repeat, don't put the plant through unwanted stress. Just feed the plant water, the large fan leaves will turn yellow and begin falling off, and you will have excellent tasting bud with zero nutrient taste. Don't just take my word for it, research it for yourself. I'll save you some time, click on the link and go to the first post by riddleme.

https://www.rollitup.org/general-marijuana-growing/409622-truth-about-flushing-10.html

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you come off kinda of harsh in your answer brother ...but I think were this whole flushing thing got started is in the food growing side ..organic food tast better nobody really knows why yet but its true ..when food is grow in pure hydro it has a higher vitamin content somtimes a higher brix level but it doent tast very good ..So they found out that flushing the hydro grown food inproved the tast ..MJ growers took the same idea just kinda become the norm ...The real problem with grow facts in general is in are schools here in america were taught there's one right answer the teacher ask a Q' and there is only one right answer for the Q...There are tons of ways to grow and for just one answer to be right we would all be doing the exact same things ..and were not theres tons of ways to do it ......I think one thing that belive with the flushing falls right into your fertigation if you feed at 700/1200 ppm tell the end your probley dont need to flush if your pushing the bar and hit 1900/2100 you might not need to "FLUSH" but you might need to scale back to at least 700 ..osmosis is a two way street ....there no one answer for any problem in growing .....

themanwiththeplan said:

the plant will not be stressed if you flush correctly. i always give 3x's the amount of water as there is soil...so if im growing in 5gal pots i flush with 15gal of water . if its 3 gal pots i flush with 9 gal of water.

the plant wont get stressed as long as you dont pour all the bottles in one after the other...give those roots a chance to breathe inbetween.

ive done this for 3-4 years with no bad results or stressed out plants.

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in a green house i use to work at this was SOP once a mouth on older plants to prevent salt buid up in peat ....

I don't mean to come off harsh but the point needs to be made.
Link Below
https://www.rollitup.org/general-marijuana-growing/409622-truth-about-flushing-10.html

billy4479 said:

in a green house i use to work at this was SOP once a mouth on older plants to prevent salt buid up in peat ....

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no one said flushing is required to maintain a healthy plant over time. It is not required pre harvest. Why starve a plant when it need nutes most at this time. Not saying go crazy with them but they still need food. Flushing is kinda like stealing from yourself.