Light level for autos?

[1212ham]

Mama always said life is like a box of chocolates. You never know what you're gonna get..... when you use bag seed.

The nodes started getting closer and she stopped gaining height a few days back, then I saw couple pistils today. Six weeks from seed, supposedly Girl Scout cookies. I'm running around 65w of 3500k strips in a 20" x 36" at the moment and have a lux meter. Assuming it's auto, what is a good light level for 18/6 hours?

EC level? I've been running Jack's 321 at 1.1-1.3 EC in a one gallon Hempy bucket. Bottom line, I don't know about autos.

 

[anexgrower]

Same light levels as photo plants

 

[KonopCh]

Same light levels as photo plants

False. It's all about DLI.

 

[anexgrower]

False. It's all about DLI.

So autos can get by with less light but for longer like 20/4 is that what you mean?

 

[1212ham]

Yes, I remembered it was about DLI with light periods longer than 12/12.

 

[LEDTonic - Daniel]

Hey,

I concur about DLI. DLI, for those unfamiliar with the term, is a measurement of light intensity over time.
The formula for calculating DLI is: μmol m-2s-1 (or PPFD) x (3600 x photoperiod) / 1,000,000 = DLI (or moles/m2/day)

We made a chart that illustrates DLI to make it easier for growers:

DLI (Daily Light Integral) Chart - Understand your plants' PPFD & photoperiod requirements

[Updated 02 March 2021] How intense light (PPFD) to expose various species to and for how long.Light intensity, or rather, how densely packed light is with photons, is measured in micromoles per meter squared per second, µmol/m2/s. This is called PPFD (Photosynthetic Photon Flux Density)...

www.ledtonic.com

Here you'll see what DLI your plants will be subjected to assuming you know the PPFD and how long the lights are on.
PPFD is another term for light intensity. The lux values you get from your lux meter can be converted (with an acceptable accuracy) into PPFD.
The conversion factor is around 60-70, i.e. 60 lux = 1 PPFD. All lux meters have different sensitivity so keep in mind that your results will never be 100% accurate, but it should give you a ball park figure.

Bruce Bugbee recommends 40-60 DLI for cannabis plants, and possibly a bit lower for early veg. I'd recommend to start at 40 then work your way up slowly. Once you see signs of light bleaching on your plants, you've hit your limit.