How bright should I light my plants?

Just bought my first decent light HGL 240 with two Chinese made quantum boards and a dimmer.
Can adjust from 2,000 to 47,000 lux at 24" from the lights (I have no idea what I'm doing).
Tried them at 8k for a couple of nights and no apparent negative effects, just upped it to 10k ..... how high can I go?

The plant on the right (Amnesia auto) seems to have doubled in height after two days.
Bottom centre Red Diesel photo, top right Thai brick clone.
Top centre, Lemon Kush photo, two centre left Orange Punch photo.

All but the smallest ones can handle up to 60k. (mh/hps. probably a wee little less for led) Keep the little ones around 20-30k for another week.
These are under a 1kw mh @ 57k Lux.

Well full sunlight is about 2000 umol or 108,000 lux. That said, these are babies. I like to keep young plants (some of yours are babies though) around 700 umol, how many lux that is depends on the light source and I don't have a conversion table for LED only these tables for HID. For the babies less for sure, more like 300 - 400 umol until they have some multibladed leaves.

.Smoke said:

All but the smallest ones can handle up to 60k. (mh/hps. probably a wee little less for led) Keep the little ones around 20-30k for another week.
These are under a 1kw mh @ 57k Lux.
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beat me to it. lol good answer bro.

Here's a site worth taking a gander at. Might help give you a ballpark figure.
Not all spectrums covered but it'll give an idea.
Everyone's grow conditions are different.
I like ~ 400 umols for vigorous vegging, lights on 24 hours and ~ 800/900 umols for flowering. 12 on 12 off.
Smaller plants like above, ~15,000 lux and build it up as they mature.
You can give them too much light which will make plants very squat.


Im at 55°N latitude.
Highest reading for sunlight I've took on an apopee meter was ~2450 umols. Around midday, around the 21st June.
Fortunately that amount of sunlight is a rarity here, once a cloud blocks the sun the number drops dramatically lol
And we get a lot of clouds!
I hope that helps.
Here's the Sun 24th June 16.04 pm

Renfro said:

Well full sunlight is about 2000 umol or 108,000 lux. That said, these are babies. I like to keep young plants (some of yours are babies though) around 700 umol, how many lux that is depends on the light source and I don't have a conversion table for LED only these tables for HID. For the babies less for sure, more like 300 - 400 umol until they have some multibladed leaves.

PPFD to Lux Conversion

www.apogeeinstruments.com

https://www.cycloptics.com/sites/default/files/Greenbeams%20PPFD%20Conversion%20Tables_0.pdf

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I'm to cheap to buy a Par meter, so luckily I found the a Apogee conversions about a month after I started growing. The math has worked so far on my cmh/mh/hps