darkness before harvest. . .

so iv read that a lot of people give their plant up to 48hrs of darkness before they harvest. first off i would like to know what the general opinion on this technique is?

my next question is, if the technique is sound - would upto 72hrs of constant darkness adversely effect the plants and flowers? my reason for asking is i have to leave for a few days and HAVE to switch EVERYTHING off for those days. i can either try to time it right so i can harvest everything just before i go, or i can give them the 72hrs and harvest as soon as i get back. the plants are around 3 weeks into flower and i go in 7 weeks so i would rather give them light right up to the switch off and deal with them when im back, hopefully they will be ready. . .

so yeah. . . i think that explains my dilemma. cheers.

...I have tried the 48 hour darkness and it does seem to make the plant a little bit more" sticky", and for some reason those plants seem to hold their smell better...but I don't think we're really doing much...IMO the plant still going to do these things when you cut it and hang it to dry in the dark, I think the key is to have high humidity the 1st 2 days of drying
...maybe it has something to do with the water...if your plant is in darkness for a few days before harvest , then the roots can still draw water........when I run my cool-mist humidtfier on high for the 1st couple days of drying , it increasing the drying days from 5-7 to 7-9...but i get results similar to the 48 darkness...( less hay smell...stickier buds)...but all this is just from my experience, I am no expert..lol...just thought I'd give you my input....good luck

long periods of dark don't affect anything so go for it works to your advantage.

thanks for the replies, have some rep.
im starting to think of other things now. its really cold here just now and along with 72hrs of darkness the grow room would most defiantly get to temps of between 11-14°c, maybe even slightly colder by the time im back. would the sudden drop in light and air circulation along with the cold temps all of a sudden and possibly a sudden rise in humidity cause some sort of mass stress freak out?

From what I've read... THC is degraded by light, and it is also a type of "sunblock" for the plant. So when you give it extended periods of darkness there is no degradation of the THC by your light...

jordanian said:

would the sudden drop in light and air circulation along with the cold temps all of a sudden and possibly a sudden rise in humidity cause some sort of mass stress freak out?

Click to expand...

I saw a grow file of a guys outdoor grow. He started it to early, an early cold snap came and he covered them all with plastic and they were covered in frozen snow for about a week. They survived and turned into 8-10 foot monsters.

right. thank you everyone. i think i know what il do now. i may post results when they come.

48-72 hours of darkness before you chop doesn't damage anything.
If it helps - obviously you don't waste electricity so it helps in that for sure.

There's a theory that in that time the stress from not having light will make the plant produce more trichomes and that there's no high radiation to degrade the trichomes.

I do it when the whole crop goes at the same time, and the plants WERE better than before the dark period.
If they were going to get there with the light on? I don't know.


The cold temps are not an issue - just get some venting in there while you'r away.
The cold temps might bring out some purple coloring on the plants, but all the stress the plants will take will not mean a thing as you'r chopping them away.

this isnt even my quote, just something i read while reading the forums.

Brick Top said:

The Stichting Institute of medical Marijuana (SIMM), the first company to sell marijuana through the pharmicies of Holland, has been investigating the medical possibilities of cannabis, together with TNO laboritories 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's growers seperated 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 increases of THC of up to 30 %, while the CBD and CBN remained the same.

Click to expand...

Desr, that doesn't say what was the THC before and the control group should have got 12\12 light for those other 72 hours so that they all get chopped at the same age.

"SIMM's growers seperated a crop of mature plants, harvested half of them and kept the other half in absolute darkness for 72 hours before cutting and drying."....i dont get what youre sayin