Targeting DLI and PPFD

Grow Cycle
1

Hi …
My light is at 12" above thye canopy. At the current power (51%) I get a DLI of 44 (which is what i was looking for. However, on a 20 hour light cycle my PPFD at this setting is only 530 (i think i want closer to 650 to 700)

Id like to have 44 DLI and 650 PPFD

My question is: … Should i adjust my PPFD to 650 and then lower my light cycle to however many hours it takes to get me under 45 DLI?

2

I never check DLI. I just go with PPFD. Ill bump my lights up until i see they are stressed then back off a notch. What stage of growth are you in atm?

3

Hi, thanks for responding. I’m in the last couple weeks of an autoflower grow. If I adjust my light to 650 PPFD my DLI will be up into the mid 50s (on a 20 hour light cycle). I’ve heard that DLI above 45 will need additional co2. I don’t think it would make a lot of difference on the current plants as they are coming down in a few days, but I’m trying to get a plan down for next grow.

4

If theyll handle 650 give it to em. Ive run autos on 18/6 at around 850 and they did fine. Id bump down a notch during the last week or so to help ripin her up

5

Yea, that sounds right. I think I would rather have a 650 PPFD for 18 hours than a lower PPFD for a couple hour longer. Thanks again for your valued reply!

6

Same here

7

Me 3. Just backed mine down to ripen.

8

I run my lights at 50-55 DLI after the stretch for 3 weeks and then back them down to 45 for ripening. Not many of us here use CO2. I have never had any issues at 55 with a PPFD of about 900-1000 for those 3 weeks. Info only, not a suggestion.

9

Thank you all for the valuable information. As I am completely new to Autoflowers, I contacted Enzo at 420 FastBuds for a little information. He sent me an Autoflower grow chart with recommendations for a wide variety of parameters. I think I might do an experiment. I’ll adjust the light to the recommended PPFD per Enzos chart then adjust the light cycle time to get the recommended DLI per Enzos chart. I have a spare 2x2.5 tent I can set up for this 1 plant experiment. I think ill grow Gorilla Cookies Auto for this experiment. Thanks again for all the replies, I do appreciate it immensely.