Autoflower seedling PPFD and DLI

[YYB]

Hello! Several months have passed since my intro post. My project was delayed somewhat, cos you know. Thanks to those who made me so welcome and helped.

Been reading up on light levels. Got into the weeds with lux, lumens, but have borrowed a PAR meter called an Autofarm LGBQM Quantum. It measures in umols per m2 per 1s. I would be very grateful for anyone who can check my maths, and my understanding so far.

I have adjusted my ES300 LED in a 2x4 tent (adjusting height and using the dimmer), to give me a stable temperature of 25c/77f whilst also measuring a PAR reading of 200. I'm running the autoflower at 24/0.

24 X 3600 = 86,400 seconds.
86,400*200 = 17,280,000 umols = 17.2mols per day at this seedling stage.

I wish I knew more about how many mols per day I should be aiming for, but any comments welcome even if it's "I don't measure that stuff but it sounds right!".

 

[The Celt]

Ideally, without added CO2, you want to be pushing your DLI into the 30+ range, but anything over 25 will grow you some nice bud.

 

[YYB]

Thanks, Celt!

I see numbers in that range you mention for established plants - is it appropriate for a seedling too?

I suppose I'm wondering if I should 'scale slowly' up to 30+, or whether the size/age of the plant is kinda irrelvant?

 

[The Celt]

Once they pass the seedling stage, you can drive the DLI up. They will let you know if the light is too intense, they will tend to “shy” away from it.

 

[NewToTHC]

I don't think I can post the link but if you search "Lighting Myths and FAQs with Dr. Bruce Bugbee" on utube it all comes together nicely (check out his other videos as well). Surprised their videos don't get more viewership, they certainly know their stuff...guess they should as they make the measuring instruments. p.s. your math looks good. I generally go the other way around and start with moles per day and divide downward to what the ppfd should be. Interesting is their research shows that one could go above 40 moles per day.