Hi all – I’ve read consistently that, toward the last few weeks of flower, PPFD should actually be reduced from 1000ish to maybe 800ish? Something similar to that. Do you do that, or do you keep your pedal to the floor?
Same with watering. I’ve heard people get a jump on drying by tapering off the watering toward the end of flower. Any real logic to that?
Thanks, gromies.
I run wide open till the end, not saying that’s the right way but it’s been working. I’m interested to see if anyone plays around with that and what their results are.
I helps a lot to keep temps down in the last few weeks of flower, so lowering the PAR value a bit is a good idea to help with that.
Lowering the temps helps keep volatile terpenes from vaporizing off ect.
Also in the last week or so, the plant is pretty much done with bulking up so it should require less photons.
Keeping the soil on the dry side is a great idea for keeping bud rot in check and overwatering in the last few weeks is a good way to increase bud rot.
Also a bit of underwatering will cause stress and this can lead to an increase in secondary metabolite production.
Personally I do both, lowering light levels will save a few bucks too.
Good luck and happy growing.
Shag
I could see lowering watering near the end as a benefit if you time it right. PPFD wise I run at 900-1000 all the way through and add a minimum of 3-4 weeks of whatever the breeder says to flower.
Yes i lower light intensity towards the end of flower, say 10/11 wks in,
at the point where transpiration has slowed right down i don’t think intense lighting is helping anymore, that’s only a guess it seems logical to me but idk for sure?
I’m also thinking when you harvest would also be relevant, some people harvest earlier when plants still have a relatively high transpiration rate, other people leave them to the last chap then harvest.
I definitely move mine to the outside to finish but don’t necessarily intentionally shade them or anything. I do harvest right as they turn on for their morning and do allow them two days of zero water to dry out a bit but that’s all I do, regardless of size of pot. Not to get a jump on drying, but to stress the plant into last ditch efforts to reproduce(increase terpene/cannabinoid production). No idea the truth to that one. I’ve always heard/learned/read that plants spend the bulk of their energy making cannabinoids and terpenes at night and use their energy to drive photosynthesis during the day so it’s best to harvest at the end of night/start of day. Everyone’s got their own experiences though!
I’ve spent a LOT of time thinking and asking about this in a LOT of cannabis forums, and usually get a bunch of hemming and hawing. Again, I don’t have ANYWHERE close to the experience people here have generally, but it’s a theory I have and am testing with every grow: it seems broadly true that most cannabis plants won’t be done until the 10 - 12 week range – similarly, maybe 15% of the time, a plant will be done in under 10. Like I said, I’m very new, so this theory may be cr*p.
Edit: My reference point here for “done” is: when growing for smoking, not pressing; when aiming for ~80 cloudy/~20 amber trichomes.
If the breeder has provided accurate flowering times then this would make little sense, but breeders are not the best trusted source as they are kinda salesmen.
This is very controversial on cannabis forums but science will tell you that some trichomes will never turn amber without withering and a withered trichome is a trichome that is harvested too late.
So unless your plant expresses what is referred to as early amber, waiting for trichs to turn amber is not the way to go.
This is science not my bro science opinion.
There is a very good thread here somewhere on this topic.
And from what I gather being in other cannabis forums, they are generally selling to fantastically-impatient teenaged boys. Who I was once. 
Hence, 8-10 weeks for everybody! lol
(But you see, this is a typical stoner move. Even the RESTAURANT industry has the good sense to consistently OVERestimate your wait for a table, so you sit down happy. Cannabis industry is more like, 'Fuck it, tell them 8 and ship it.")
Thank you. I take you at your word and that’s my new assumption, until it’s displaced by a better theory. I’m being serious, fyi.
I really prefer a creative, cerebral, awake high. If all the trichs could be cloudy, that’d be just fine for me. I was mostly looking for a few amber simply because I knew then that I probably wouldn’t be too EARLY to harvest it. (The first time I saw clear, cloudy and amber all at the same time, my OCD side went off like a roman candle. 
)
Here is a few links to check out.
Some very cool pics here.
Might I suggest you find a point where some of the trichs are cloudy but most are still clear.
If the high is not quite there let more get cloudy but not all of them just yet.
If that is still not what your after let most of them if not all get cloudy.
But if the trichs are starting to dry up and wither you may have waited too long.
Unless you are looking for a sleepy type of high.
Some people consider “day 1 of flower” as the day that the lights are flipped. Others consider “day 1 of flower” as the day that the plants start to bud. If you use the latter, the breeder time is usually pretty close. I assume they use it just because it sounds better, and really it’s more accurate because the plants are basically still in veg until buds start to form. The stretch is like super vegging.
I gotcha, and that sounds good. In my very limited experience, it seemed like a long wagon train: at some point, mostly were cloudy. Maybe 5 percent were still clear, and 5 percent were amber, but 90 percent were cloudy. Thanks for this, man.
Right after you wrote, I looked these up and found the second article. Both are great. Thank you.
I’ve heard of people switching to 18/6 for the last 7-10 days of flower to give the plants an extra boost at the end but never heard of backing off.
I have a theory that PPFD may not need to be reduced if water is consistently available.
I’m testing this with my current setup. Flowering at 11/13. PPFD is well over 1K and I’ve noticed plants can manage but require more refills of water. I’ll see if final results are worth it.
Interesting theory, let me know how it goes? I made the point about my managing heat, but what about light and its affect on trichome health just before harvest? It DOES make intuitive sense to me that we should be more gentle at the end – perhaps THAT is why backing off the PPFD?
I did something like this because I had no choice and I wouldn’t say there was an improvement but it didn’t seem to hurt them any.
I heard about it through Rasta Jeff (breeder for Irie genetics). He claims bigger weights from the switch but when I tried it, I didn’t notice a difference. Maybe if you run the same plant for a while and had data of what it produced with and without the switch you could make a case.
It’s also a good trick if you plan on a reveg 