I love watching them grow often . I stay in 1st floor of the building in a high traffic area so I suppose the co2 released from vehicles nearby would contribute a lot.
The more the merrier!
The first quarter of the year in my location seems to have a higher DLI. Can see the Veg state of the plant is capable of having more of the light. I have adjusted the grow light, such that the sunlight and grow light doesnt hit the same area of the plant.
Well, that puts paid to my theory-you're not in the Great White North (Canada)! Where are you located - Aus?
Re. the growlightmeter.com DLI chart - it's very popular but the DLI values in that chart have no basis in research and are well below the light levels where cannabis will thrive. Having said that, my experience has been that. the ramp up veg for "C02 required" is about where my non-CO2-enhanced plants max out. However, the idea of dropping DLI in flower and then slowly ramping up is novel and unsupported by data.
Shane at Migro is another source that recommends "modest" levels of light and, as with GLM, he does not reference any research in the videos where he provides that recommendation.
I'm not arguing that you won't get a decent crop by following those light levels but, as Bugbee says, you will be "leaving money on the table".
The following table was quite interesting:
For every 50µmols increase in PPFD, the dry weight yield increased by about 5%.
Having said that, for the first few grows I did, I fed my plants with modest levels of light. Within a couple of months of starting to grow cannabis, I had read a number of research papers and had watched and rewatched all of the Bugbee videos but I still stayed with light levels in the 40's. Last summer, while watching a de Bacco video (YouTube) for the nth time about light I finally "turned it up to 11".
My approach is to get plants to the light saturation point ("LST") ASAP. That's 800-1000µmols for cannabis (strain dependent). At that point, the limiting factor is the amount of CO2 available to the plant (photons and CO2 are inputs to photosynthesis with O2 and glucose being the outputs). As Bugbee states in multiple videos and in published research, they have pushed cannabis as high as 2000µmols, in a CO2 enriched environment, and net photosynthesis continued to increase.
I don't run CO2 but, as you'll see from my grow journals, I provide my plants with a lot of light. Many growers routinely run their plants close to the 1000µmol mark, myself included. ATM, my plants, two Chemdogs at day 21, just went from a DLI of 29 to 35 and I expect to have them in the low 60's in the next few weeks.
My lighting plan for this grow:
Yeh, up at 0400 - just woke up in the middle of the night and, lo and behold, my WiFi network was on the fritz…
This is the DLI chart for my location in Orange County, Southern California (next door to LA county)