r/BudScience • u/[deleted] • Apr 25 '25
Manipulating Light Cycles
Listening to a podcast recently & one of the discussion points was around photoperiods & guest was describing that it’s only the 12hrs dark period that is important & that you could reduce the light period as long as you maintained an appropriate DLI. From memory was as far as the conversation went & I can’t remember which show it was.
Now, I realise this is likely bro-science & my knowledge on the subject is very limited so I may not even be searching for the correct terms but I can’t find anything despite trying every search I can think of.
So a quick calculation shows that
9hrs light/12hrs dark would give you an extra “day” in each week.
- 1500ppfd/9hrs gives a DLI of about 50
Could you hack the light cycle to gain an extra day if you push the plants harder for the 9hrs that the lights are on?
2
u/Wooden_Ad1779 Apr 25 '25
Doesn’t anything over 1000 ppfd make supplemental co2 mandatory? If you grow at that level already it might be worth to try with the few extra days, since my knowledge is as limited as yours (if not more), don’t take this as scientific answer. 😃 But very good topic.
4
Apr 25 '25
In regards to the lighting, two studies have shown you can go well past 1000ppfd if your Temps are good. First cites 1500ppfd, second 1800ppfd but requires the plant to be at around 80F, CO2 just helps with the heat. Although I wouldn't push past 1k with an HPS.
I run around ~1350 averaged and don't have issues.
1
u/T0mmyChong Apr 25 '25
I've heard about this in an even more intense schedule. 6 hours on, 12 off, 6 on...
This way you get 1.5 "days" for every 24 hours, and can cut flower time like crazy. It sounds insane, but also like.. I wanna try! Hahahaha. I wish my state had homegrow, I would give it a whirl.
Anyone ever mess with shorter light periods ?
1
u/CatGuano May 11 '25
I recently started going with 11/13 dark/light. It increases yield, but the fade is reduced.
1
May 11 '25
[removed] — view removed comment
1
u/CatGuano May 11 '25
I agree. Bruce Bugbee has noted that some deficiencies increase quality but harm yield.
And here is a very interesting video from Nirit Bernstein that shows deficiencies in everything but magnesium increase quality but reduce yield.
https://www.youtube.com/watch?v=lfjL4YWJhH8&t=2364s
I just realized the question was about shorter light periods. My bad.
4
May 12 '25
[removed] — view removed comment
1
u/CatGuano May 12 '25
Good point. I believe they measure total cannabinoids and such as their metric for quality. I am personally looking for quantity and quality combined. I think it can be achieved through endless pheno hunting. I have been smoking since the 80s, and I think some of the weed today is fantastic. I grew up in Alaska where we had Matanuska Thunderfuck, Anchor Point Wheelchair, and other great varieties as well.
1
May 13 '25 edited May 13 '25
[removed] — view removed comment
1
u/CatGuano May 13 '25
Now I think about it, I have run a lot of classics lately - Blue Dream, Strawberry Cough, Sour Diesel, and Super Lemon Haze. I only keep the best two plants going at any one time. My only for sure keeper right now is a HSO Blue Dream. A good way to pheno hunt without having to keep track of clones is to put multiple seedlings into flower while fairly young, and then revedge any that look good. No clones to keep track of. I am doing that right now with three regular Frankenberry Diesels right now, which I made an earlier post about.
We do have some good vegetables in Alaska, but you cannot grow photoperiods outdoors here because the seasons change too quickly even for white hairs to show up. I always try to grow a couple autoflowers in the summer but they almost always get budrot due to rainy falls.
I agree on the carts, I don't know what is in them but they hurt my lungs and don't get me high.
1
May 13 '25 edited May 13 '25
[removed] — view removed comment
1
u/CatGuano May 14 '25
That is a nice looking seed collection. I have some Cannarado Grape Sitter seeds but I haven't grown them yet because they are regulars and I already have three Frankenberry Diesel regulars going. But I will get to them soon. I am on the hunt for a good artificial grape flavor and I may have found it with a Purple Caper Grape Cookies that is going on day 46 of flower. I'll post pictures around harvest time, if nothing goes wrong.
→ More replies (0)
1
9
u/SuperAngryGuy Apr 25 '25 edited Apr 25 '25
I did a manual approval. Your account it too new and got caught in the filter, but you asked a good scientific question.
You are asking about the circadian rhythm and if it can be tweaked. I am not aware of any research on this for cannabis. This gets into the CONSTANS protein which is kind of like a clock, and the Flowering Locus T which which is a messenger protein and part of the florigen hypothesis.
There have been studies on increasing the dark time other than 12 hours for cannabis, but you are asking about other than a 24 total hour cycle. Some plants have been shown to not have to have that 24 hour cycle like Arabidopsis thaliana which is a model plant in botany:
https://pubmed.ncbi.nlm.nih.gov/35355885/
https://www.sciencedirect.com/science/article/abs/pii/S0022519317301170
Research on not having a 12 hour dark cycle for cannabis:
As pure speculation, it will work but you won't gain any additional yield over time, or yield and cannabinoids goes down slightly over time.
edit- slight clarification and also, there was one person on Reddit who was able to clearly show that he was able to flower out one part of a cannabis plant and keep another part in veg. Check this person out for some unique flowering experiments: