Lower light hours before harvest?

apbx720

apbx720

Well-Known Member
what up riu! noob here. first grow. im growing a few strains that are an 8 week cycle. does that mean they finish at the beginning of week 8 or the end of week 8? i know its not exact, and that the plants will tell me when theyre ready, but im trying to plan a flush. so im in week 7 (day 50) of an 8 week flower cycle and i have a few questions...

1. should i lower light hours at the end of the cycle to boost trics and what not? if so when do i start lowering light hours and for how
many hours each day? 10/14?? 9/15?? details please.

2. would anyone recommend leaving them in the dark for the last few days? what are the advantages of more darkness?

any comments would be greatly appreciated. i will post pics if needed but i must apologize for the shitty quality. thx
 
rocknratm

rocknratm

Well-Known Member
for flower 12 hrs on 12 hrs off. complete dark during off hrs. dont change the patterns.

And I count from first visible signs of flowering (little pistils) to the end of the week number (so end of week 8 or even 9 depending when u started counting)
 
K

KushDog

Active Member
On "white" strains , some people lower the light to 7-8 hours on , and some times keep the plant in complete darkness for up to a week or two it make the plant stess out and think its dieing and pours on the tricorms..
8 week harvest time is just a guide line for when to expect it to be ready. so i would say 8-9 weeks.
and I leave all my plants in 48-72 hours of darkness before harvest

and for your flush, i am not going to give you any advise there, because someone will dis agree and say feed till the end. so I have no coment on that
 
massah

massah

Well-Known Member
all harshness attributed to "not flushing before harvest", is cured by a proper dry/cure...you have many people that don't cure their weed properly that blame it on not flushing their plants...I didn't flush my last grow...I haven't cured my bud completely yet, and it tastes and smokes just fine :)
 
kush groove

kush groove

Active Member
1. changing the light schedule can work two ways when flowering.....increasing darkness will trick the plant into thinking the long nights of winter are nearing an end and will increase ripening speed of the bud; increasing light hours will increasing fattening of the buds by giving the plants a few more hours to grow...16/8 is the max for light hours at the end of flowering

2. ive left my girls in darkness for before harvest and wasnt sure if it made a difference....all the growing books i have speak nothing of it.....some people swear by it, most say its just a myth

also just another pointer...try not to lean on set harvest dates too much......harvest when the triches are where you want them......im growing organic now so i gave up on flushing a few grows back and let my girls grow all the way through the flowering period
 
K

KushDog

Active Member
kush groove said:
1. changing the light schedule can work two ways when flowering.....increasing darkness will trick the plant into thinking the long nights of winter are nearing an end and will increase ripening speed of the bud; increasing light hours will increasing fattening of the buds by giving the plants a few more hours to grow...16/8 is the max for light hours at the end of flowering

2. ive left my girls in darkness for before harvest and wasnt sure if it made a difference....all the growing books i have speak nothing of it.....some people swear by it, most say its just a myth

also just another pointer...try not to lean on set harvest dates too much......harvest when the triches are where you want them......im growing organic now so i gave up on flushing a few grows back and let my girls grow all the way through the flowering period
Click to expand...
I agree 99.9% almost 100% You are correct , But i was allways taught that 15 hours on and 9 off was the max you can do in flower with out it going back to VEG? I am not saying your wrong, but was just wondering about 16 hours on with out reverting to veg. Thanks for the input
 
mccumcumber

mccumcumber

Well-Known Member
A plant will not finish faster if you increase the dark period. Increasing the light hours definitely will not fatten the buds up at all. If anything you will reveg and stress your plant. There has been speculation, however, that the potency will go up if you increase the dark period.

Before I get some angsty posts from "growers" I'd like to point out the science behind it. If you don't know what meristems are, look them up, they're important. In short, the SAM (shoot apical meristem) is your source of all the above ground "organs" in your mj plant. They are the plant stem cells, and what is grown during your vegetative period. Once the hours get shorter, and more Fr light wavelength is present (red spectrum lighting, found in your hps. That's why people say to flower with a hps) your plant goes from growing SAM to growing inflorescence meristems which then turn into floral meristems. That's why there is a one week period of stretch from veg to flower. Floral meristems are what produces your flowers (buds), and need around 12 hours of darkness to continue growing.

So what happens if you put the light on for 16 hours? Well, the floral meristems slow down in growth. This actually makes your buds "less fat." Funny enough, if you keep doing this for an extended period of time then the floral meristems will revert back to SAM... oh no! What does that mean? Your future growth will be vegetative growth, and you will have effectively revegged your plant.

Obviously only raising the amount of light you give your plants for a short period of time won't reveg the plant, but it won't do anything beneficial either, and has the potential to be harmful if anything. Also, I bet your electric bill is high enough, why pay more for it?


Now, onto less light.

The way THC is put on your buds (or at least is thought to) is a protection mechanism. The plant is protecting the buds from the sunlight. I have read, there really aren't any scientific books about mj so I don't know accurate this is, that THC is applied during the dark period. It's a sort of sunscreen basically that gets put on each night. Do not get confused though and think that your buds are what's telling your plant to put on the THC. Your leaves are the plants indicator of how much light it is getting, and how much THC ought to be put on. So if you chop all your leaves during flowering you are effectively getting way less out of your plant. Back to the sunscreen, the theory is that during the end of flowering your plants want to put on a lot more sunscreen as there is more area to cover and more need for it. So that's where you get people saying lower your light schedule and leave the last three days dark. I don't know how accurate any of this is though, however, I have done it myself with fine results.
 
kush groove

kush groove

Active Member
KushDog said:
I agree 99.9% almost 100% You are correct , But i was allways taught that 15 hours on and 9 off was the max you can do in flower with out it going back to VEG? I am not saying your wrong, but was just wondering about 16 hours on with out reverting to veg. Thanks for the input
Click to expand...
ive actually done 16/8 for the last two weeks of flowering and the plants did not revert to veg.....not sure how much of difference it made in the bud though......thc production is based on genetics and genetics alone, i wish i knew this before, coulda saved myself some cash on nutes

mccumcumber said:
A plant will not finish faster if you increase the dark period. Increasing the light hours definitely will not fatten the buds up at all. If anything you will reveg and stress your plant. There has been speculation, however, that the potency will go up if you increase the dark period.


Before I get some angsty posts from "growers" I'd like to point out the science behind it. If you don't know what meristems are, look them up, they're important. In short, the SAM (shoot apical meristem) is your source of all the above ground "organs" in your mj plant. They are the plant stem cells, and what is grown during your vegetative period. Once the hours get shorter, and more Fr light wavelength is present (red spectrum lighting, found in your hps. That's why people say to flower with a hps) your plant goes from growing SAM to growing inflorescence meristems which then turn into floral meristems. That's why there is a one week period of stretch from veg to flower. Floral meristems are what produces your flowers (buds), and need around 12 hours of darkness to continue growing.

So what happens if you put the light on for 16 hours? Well, the floral meristems slow down in growth. This actually makes your buds "less fat." Funny enough, if you keep doing this for an extended period of time then the floral meristems will revert back to SAM... oh no! What does that mean? Your future growth will be vegetative growth, and you will have effectively revegged your plant.

Obviously only raising the amount of light you give your plants for a short period of time won't reveg the plant, but it won't do anything beneficial either, and has the potential to be harmful if anything. Also, I bet your electric bill is high enough, why pay more for it?


Now, onto less light.

The way THC is put on your buds (or at least is thought to) is a protection mechanism. The plant is protecting the buds from the sunlight. I have read, there really aren't any scientific books about mj so I don't know accurate this is, that THC is applied during the dark period. It's a sort of sunscreen basically that gets put on each night. Do not get confused though and think that your buds are what's telling your plant to put on the THC. Your leaves are the plants indicator of how much light it is getting, and how much THC ought to be put on. So if you chop all your leaves during flowering you are effectively getting way less out of your plant. Back to the sunscreen, the theory is that during the end of flowering your plants want to put on a lot more sunscreen as there is more area to cover and more need for it. So that's where you get people saying lower your light schedule and leave the last three days dark. I don't know how accurate any of this is though, however, I have done it myself with fine results.
Click to expand...
no angry posts from me brother...as far as increasing ripeness and fattening buds, thats a technique i read about in two grow bibles that i have, which doesnt make it a fact, but it is practiced....i dont know much about meristems ill look them up, but i do know 12/12 isnt natural in nature so a small change in the lighting should be mimicking mother nature and beneficial to the plant if done correctly.....just an opinion
ive never heard the sunscreen theory but it sounds about right.....the plants need light for energy to produce thc, but thc production is done at night....so which is better little more light or a little more darkness....who knows......i think most would go with more darkness....personally i flower all my girls at 13/11 with the first 15 minutes of led only last 30 minutes of led only
 
V

VanishingToaster

Active Member
i've only read half the thread for that i apologise but i've seen a lot of people claiming that leaving plants in darkness before you harvest increases the trichs.

this is one of the more debated subjects and there is no real proof either side as to whether it affects plants or not.

i have tried this, i used two plants not from the same mother but of the same type and there was no real discernable difference. for it to be a fair test you should really use cuttings from the same mother as they both have identical genetic potential.

if i was to offer you any advice it would be to make up your own mind about flushing and keep them in the light, can't think of any other plant that has a darkness specification apart from purple asparagus which is grown in the dark to achieve the purple colour.

cannabis plants do produce more resin if they are subjected to higher amounts of ultra violet B in the last week of flowering, maybe hook urself up with a reptile lamp. i've not tried this but have seen grow charts with a UV final week. think it was Dutch Pro.

all in all whatever you decide to do post it and i wish u all the best
 
apbx720

apbx720

Well-Known Member
KushDog said:
On "white" strains , some people lower the light to 7-8 hours on , and some times keep the plant in complete darkness for up to a week or two it make the plant stess out and think its dieing and pours on the tricorms..
8 week harvest time is just a guide line for when to expect it to be ready. so i would say 8-9 weeks.
and I leave all my plants in 48-72 hours of darkness before harvest

and for your flush, i am not going to give you any advise there, because someone will dis agree and say feed till the end. so I have no coment on that
Click to expand...
lol i wouldn comment on it either. ive noticed the same thing. but im still gonna flush. maybe next crop i wont, n see what happen. so u have noticed more tric production compared to keeping 12/12? is there a sacrifice, like less growth at the end with lower light hours?
 
apbx720

apbx720

Well-Known Member
VanishingToaster said:
i've only read half the thread for that i apologise but i've seen a lot of people claiming that leaving plants in darkness before you harvest increases the trichs.

this is one of the more debated subjects and there is no real proof either side as to whether it affects plants or not.

i have tried this, i used two plants not from the same mother but of the same type and there was no real discernable difference. for it to be a fair test you should really use cuttings from the same mother as they both have identical genetic potential.

if i was to offer you any advice it would be to make up your own mind about flushing and keep them in the light, can't think of any other plant that has a darkness specification apart from purple asparagus which is grown in the dark to achieve the purple colour.

cannabis plants do produce more resin if they are subjected to higher amounts of ultra violet B in the last week of flowering, maybe hook urself up with a reptile lamp. i've not tried this but have seen grow charts with a UV final week. think it was Dutch Pro.

all in all whatever you decide to do post it and i wish u all the best
Click to expand...
i like yr approach. i am planning on experimenting more in the future in order to obtain my own factual results, but this is my 1st so im interested in finding out other peoples experiences with experiments that they have done. but i have heard good things on uvb. ed rosanthal is a supporter of uvb. that dudes the shiz. i looked at a reptile light once but didnt buy it because i was concerned w the added heat it would produce. i battle heat already. have u tried uvb?
 
V

VanishingToaster

Active Member
just something i was looking into that seemed to make sense. no doubt tho it wont be long before it disputed by somone who gets the dosage wrong and is convinced it made no differene
 
apbx720

apbx720

Well-Known Member
VanishingToaster said:
just something i was looking into that seemed to make sense. no doubt tho it wont be long before it disputed by somone who gets the dosage wrong and is convinced it made no differene
Click to expand...
ive read to supplement w 10% of total wattage. so 1000w hid u would use a 100w uvb. that sound right?
 
mccumcumber

mccumcumber

Well-Known Member
I don't think a grow bible is a reliable source. I dont event think jorge cervantes grows, cause most of the shit of his i read sounds like horseshit to me. I got my info from a botany and plant science text book, so I'm gonna stick with that. :)
 
RockCreekRanger

RockCreekRanger

Well-Known Member
Good question that I also had, thanks. From what I have been gathering, it takes more that a few days for the plant to adjust to light change. Don't really know, but cycles..... I wanted to do that with my snowryder. The specs say 18/6 all the way through because it's an autoflower. But just like flushing wouldn't it need that food for heavy production? Reducing nutrients and light would decrease yield right?
 
resinousflowers

resinousflowers

Well-Known Member
massah said:
all harshness attributed to "not flushing before harvest", is cured by a proper dry/cure...you have many people that don't cure their weed properly that blame it on not flushing their plants...I didn't flush my last grow...I haven't cured my bud completely yet, and it tastes and smokes just fine :)
Click to expand...
it may taste fine,doesnt mean it is fine.
 
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