Just a FWIW !
I'm on day 22 of my first grow with a
Phlizon 640w LED, long time die hard HID user
The first germinated seed to emerge in a solo cup was under 9,000 lux, she was looking stretchy....
Two days later I raised the power to 13,000 lux and all six plants were growing somewhat normally with much less stretch than I'm used to !
Six days later I went to 13,000 lux and six days later to 26786 lux.
Three days later I went down to 24,000 because I have Never seen such short seedlings.
Topping and training was going to require magnifying glasses
On day 17 I transplanted four plants to 5 gallon pails with GroBuckets, three in ProMix HP, one with 5/1 coco/perlite.
The remaining two into 2 1/2 Imperial gallon fabric pots with 4/1 coco/perlite, 30,000 lux. Feed is Mega Crop one part...
Under a 600w MH/HPS with only three power settings I would put my light at 30" and 50% power and let the plants grow up to it...
Now with LED And an infinite power knob I can pay much more attention and dial it in closer to ideal.
One grower I follow who does good work starts his seedlings at 550 par
Right now I'm at 450 par at plant top height (using a conversion factor of .015 x lux) at 28"....
I almost wish for the vertical growth I was getting with HID
These are all sativa/sativa dominant strains and the reduction in vertical growth will be Welcome down the road !
Temp at plant height is 78, rh with a humidifier is ~50%. Best I can do with my budget set up...
Middle bottom is a five days younger Hawaiian Snow. The fabric/coco girls seem to be taking a little longer to get with the program
Topping/training will commence tonight !
Maui Wowie
Acapulco Gold
I have the Photone app and a PPFD meter on my phone but I find I get the most accurate readings with a Lux Meter !
Not sure if I will bother with a dedicated lux meter, this is a budget grow after all
If you have the ability to fine tune your environment further I recommend looking at VPD, choose a chart that allows you to enter the leaf temperature /room temperature and rh...
Cheers