I'm not dropping PPFD. Someone raised the issue that Westmoreland had discussed that in his video and I went back and listened to the vid again (at 1.5 speed, granted) and didn't hear him say that. My current grow has been a bit of a PITA because, unlike my previous three or four grows in which I grew only one plant, I decided "Well, I'll try two" and it wasn't worked out too well.
I've seen this pattern in past grows; I refer to them as "Twins grows", named after the movie starring deVito and Schwarzenegger. Donna and Erica were Orginal. Glue seeds from Nirvana and were the best two of three seedlings. Early in veg, Donna was clearly larger than Erica and the difference has continued to increase.
About two weeks ago, I gave up on canting the main light and I moved in a Vipar XS1500 for Erica. Donna's canopy has become pretty uneven so I've had to resort to putting "lamp shades" around the light bars. A "lamp shade" is a piece of bond paper, wrapped around the light bar, fixed with Gorilla tape. I slide them along the light bar, as needed to control PPFD. Hang height in the photo below is about 12" which a recent increase but I need to do that to try and get the lightcast evened out.
View attachment 5441431
My PPFD readings from yesterday include only the colas. The rest of the canopy is, unfortunately, down in the 700's.
View attachment 5441432
vs PPDF from about a week ago
View attachment 5441433
I spent a fair amount of time looking for a new light (my flower light is a model year 2020 Growcraft). The Gen 1 Spider G/SE4500 was my weapon of choice, with it 430 watt driver. Before I pulled the trigger on it, I bought and tested the new MarsSP3000R. That gives out a huge amount of 660 light (>90% I'd say) but I couldn't overcome the PPFD map and the heat output was prodigious.
By the time I returned the Mars, Spider pulled the high wattage 4500's off the market and released gelded versions with a 320 watt driver. "Damn you Murphy, you've won again!". But that wasn't the case.
After eschewing "add on lights", due to there being no PPFD data, I resisted the issue and, as of last week, shoehorned a pair of
Spider R80's in the tent. They're an absolute bargain. I'm getting 300±µmol of 660nm light for 80 watts. The increased PPFD allows me to turn the dimmer on my Growcraft down from 300-330 watts to 170 watts and I'm getting
very similar PPFD's on the plant.
The drop in wattage on the Growcraft looks to have dropped ambient temps by a couple of degrees. For my current grow, I'd like to have that heat back because we're having a cold Fall here in Souther Commiefornia so temps in my garage are down a bit.
11//22/24—Yikes! (and, yeh, I'm old - 68 years worth)
View attachment 5441436
Daytime ambient temps are <=82 now and temps at the tops of the colas are 75±°.
Uneven canopy.
View attachment 5441437
In this photo of Govee sensors, 2 and 4 are in the Koolatron cannabis fridge that I use while 1 and 3 are hanging in the canopy and 5 is the sensor that's visible in the photo at the back of the plant (the sensor on the right is a PulseZero).
While the temp in the plant (#1 and #3) are below 75, which is where bud rot likes it, RH is low enough to keep bud rot at bay. #5 is right at the top of the canopy so 76 and 62 should be good to hold of bud rot. I lost a very nice plant to bud rot a year ago and don't want have that happen again.
View attachment 5441438
Oh, you wanted an answer to your question!
As a result of switching to the R80's, there's less heat in the tent. Ambient temp is down and flower tops are 75° so I'm in good shape for temps.
It takes some time to futz with the lamps shades, the dimmer %, and the hang height (the light is canted, higher in the back) so PPFD is pretty much the same.
CO2 - I'm in a tent so it's ambient CO2.
[edit]
PPFD on Erica is pretty good but there aren't really colas, per se. Buds are forming but they're even with the canopy. These are the PPFD values from yesterday:
View attachment 5441439
