I bet 2 things: 1 - Dr. Bruce Bugbee almost certainly has an actual scientific answer
2 - it very likely has something to do with the slowed metabolism of the plant; the transition phase (between veg and flower, aka “the stretch”) is where your plant will expend the most energy most quickly throughout the entire grow process. I’m expecting that during transition, she’s actually able to make full use of the entire amount of light provided at 50 DLI. Some plants very likely can continue to utilize that much through most of the grow, but I think “on average” more plants than not don’t really have that high of an energy demand while they shift the gears from “transition” into “bud building.”
I’m just taking an educated guess, but it seems feasible.
Apologies for my less than helpful response earlier, my inner (too much) sativa was trying to be efficient and I left the charts out!
I bet with @Graysin on Dr. Bugbee knowing. I’d supplement bet #2 by suggesting that part of it may also have to do with the change in light cycle, which is why the chart doesn’t really change as much for autos. A direct input in the calculation is seconds per day of light, so when you take 3600 seconds per hour and multiply by 12 hours instead of 18 (or 20 or 24) the DLI changes accordingly. It’s a measure of the amount of light provided per day so autos don’t always change light cycles. With photos, we don’t turn lights down to get less DLI on the chart, instead it’s the fewer hours of exposure to light that does the same thing. Rather than jack the light up that high right away to make up for the less hours of light, the chart suggests an acclimation while continuing to raise the intensity of the lights. Notwithstanding adding UV during flower to change the kind of light the flower gets.
Not sure my guess is as edumecated, but part of it relating to the light cycle makes sense to me. Y’all can say duh, and it won’t be the first time
The dip is due to no change in light intensity but light hours reduced to 12/12. This is necessary to induce flower. Then light intensity is ramped up to peak DLI for dense flower.
I may be outside my pay grade, but I think we want to reduce the daily light (DLI) to induce flower then build it back up a bit while keeping in mind that we’re sort of simulating fall at that life stage.
Yeah I can see how that’s the working theory. The reason I ask is because I have had no issues transitioning plants from 18/6 to 12/12 regardless of DLI. I believe my veg tent DLI is ~35 and the DLI in flower is 50-55. I was under the impression and belief based on this that my (photoperiod) plants only care about daylight hours, not daylight intensity.
I always wondered about that too. Let’s try some math!
If you’re in veg running 18/6 and your lights are on 80% to get a DLI of 40, you need to crank them up to 100% to get a DLI of 50, and that’s running 18/6. That would be 50DLI/18hours or 2.78 DLI per hour. To achieve 50 DLI in 12 hours, you would need 50/12 or 4.17 DLI per hour, an increase of 4.17/2.78 1.498 times as much light or 150% more.
Without adding more lights and maintaining the same distance from lights to plants (since lowering lights wil increase DLI without turning up intensity), you would need to finish your veg period with the lights at 60%, then crank them to 90% when you cut the hours to 12. gives you 10% extra to really crank them at the end!
But if this simulates nature, the intensity of the light should decrease as the sun moves south towards winter time, not increase to make up for lost hours. So it doesn’t simulate nature, rather maxes out what the plant can handle. Wihich is probably why people can grow good bud without really cranking DI at the end, nature doesn’t!
I don’t have that option, my 465w light is at 100% throughout the grow, once they hit their stride!
Has Bruce updated his information in the last year? Because the charts are not from Bruce they are from the DLI app, or at least the one is.
Bruce was giving us limited information last time I was digging deep but he did say something along the lines of:
We have noticed that clones can accept very high levels of light very early on, unlike previously thought, as they are mature plants.
My memory is hazy and I can’t remember exactly what he has and hasn’t said abiut DLI but I do believe he said that plants don’t respond beyond 60 DLI without co2
With my own extensive experience I have notice high levels of light late in flower cause fox tailing to be exhibited at higher rates then if the lights are dialed down a bit.
With that in mind when we think of plants in Veg, we know that more powerful lighting will keep a plant shorter and stockier, so I encourage people to read their plants node spacing while in veg.
We also know that stretching occurs Durring the flip, be it an auto or a photo. So high light levels at this time are encouraged to help control that stretch as much as possible.
That builds a bit of a curve.
Dial the lights up as you decide how much node spacing you want and how stocky you want your plant to be, smash it with light before stretch and then keep it high until the buds are fairly formed.
All Durring this time VPD and fresh air have to be controlled or the high lighting will cause its own issues.
Have you seen him suggest using this schedule? I was watching one of his vids where her was talking about going as high as 60 and didn’t mention dropping it in flower. I need to watch more of his stuff
That’s my impression too. 60+ maximizes yields, no mention of easing up at the end of flower.
Honestly I don’t ever adjust my lights, I probably should, but I think my plants yield alright considering how little love they get. It likely has to do with getting hammered full blast lights.
Long time no post! Sorry about that! But we’re still going strong over here. I’ve switched to organic which hasn’t been the easiest transition but we’re still making it work. Worst comes to worst we’ll go back to using Jacks 123 which so far has been the easiest to use in terms of no burn or deficiencies when used alongside calmag. I think the only issue I had was making sure each part fully dissolved before mixing the next part, or just plain being entirely too baked and forgetting to stir before adding the next what I found to work best was to use 1/8-1/4 gallon of very hot water so that they dissolve nicely and then adding cold water to make the temperature what it needed to be. After doing that I had no issues with mixing and even produced this beauty
I’ve also learned how to successfully clone as well as use STS to reverse branches to collect pollen which I’m super excited about! If I had a tip for STS I would say to cut clones and spray a clone as opposed to a single branch and when I go to cross with the pollen it will also be on a clone bc I not only will it save space but I don’t have to worry about losing energy to seeds instead of bud.
As of now we are currently on Day 34 for both the Cherry Cookies (left) and Grandaddy Black (right) and I honestly don’t know what day my Afghani Clone (middle) is on its probably somewhere around day 70-80. Ivr kept her in a solo cup until a couple days ago when I transplanted into a 2L bottle I wanted her to be able to have a a better shot at flowering by giving her more soil/nutes but I also don’t have the space for another pot so here we are.
You probably can’t tell from the photo but the Grandaddy Black has primarily 3 finger leaves and then just starting to show 5 finger leaves but I’m so proud of her bc either due to genetics or to me accidentally ripping off the initial fan leaves she only had cotyledons! It took a whopping 30 days for her to show leaves and not only did she catch up but surpassed the Cherry Cookies in height, she’s the dankest plant I’ve had in veg she already stanks up the room which is nuts to me. Either way I’m looking forward to what they produce as well as their clones. I will be crossing the Cherry Cookies and Grandaddy Black with each other as well as the Afghani Indica and GG pollen I have collected! I owe everything to this site and the awesome people on here primarily @Docnraq and @Graysin and I plan on trying to share the love as well as my experiences to return the favor! Thank you two for everything you’ve done for me!
I have very high hopes for the Cherry Cookies and we’ll see on the Grandaddy Black and the crosses to be. But I will gladly swap pollen with you anytime
what I found to work best was to use 1/8-1/4 gallon of very hot water so that they dissolve nicely and then adding cold water to make the temperature what it needed to be. After doing that I had no issues with mixing and even produced this beauty
