My friend has been right about everything, but we disagree on distance/intensity of LED lights...Opinions?

Hi, I am a first time grower.
I wont post stats, since I have no issues so far (3 weeks in)
Only relevant stat - I have 3x3x6 feet tent and 240w Kingbrite board with some cree reds.
I also have a lux meter

HOWEVER, I have a friend who grew a lot of herb 10 years ago ( he has about 3-4 year experience)
I am learning a lot from him and often cnonfirming his opinions on reddit and other forums. He really seems to know a lot about plant physiology and the smaller details/mechanisms.

HOWEVER - he says I should keep the LEDS about 5-6 inches from plants at 100% for ALL TIMES.
Everything I read says the oppsoite - seedlings need less light, maybe 10-20k lux max, vegetative stage a bit more and flowering some more (up to 100k lux)

So it goes kind of funny - he comes over to answer some of my questions and check my progress and IMMEDIATELY lowers the leds/turns them up to 100% (They deliver MOREt than 100k lux this way)

I have been keeping them some 20+ inches from top of plants at 30-40% intensity.
I am getting about 30-40k lux which seems to be above all guides I have seen.
So he goes away and I turn the light down and pull the up hahah. When he comes back, I put them in the spot he last left them LOL

So guys - my question is this. I dont want to grow "his way" when it comes to lghts but I lack knowledge on "light stress". H ebasically says, there is only heat stress and is closed to the opinion that there CAN be too much light.

What should I do? Since we arent the best buddies, I could lose his expertise with other things (Lst, nutes etc), but I also dont want to blast my plants with 100+k lux at 3 weeks of age......

Thanks.

Go to YouTube and watch the videos by Dr Bruce Bugbee. Get answers to questions you have now and will have in the future. In short your friend is wrong.

If his main grow experience is 8 to 10 years ago he doesn't have much knowledge of the current state of led lighting which has progressed enormously in that time. I bought my first leds 10 years ago and they don't compare to new units.

It depends on the light. All I know is if I turn my light past 30% my plants start to have issues.

Not sure if I can even go 100% in flower.

And it is probably 2-3 feet above the tops.

Light pulls 120 watts from the wall in a 2x4 tent at around 30%.

The main thing is read the plants.

If the plants are ok with it....then it is ok.

If you start to have issues. Adjust.

Gotta learn to read the plants. Read the color of the leaves.

Modern led lights I would say at least 18 inches or more away depending on intensity, I still just leave my arm there for awhile, if it dosent feel to hot on me It tends to be ok 4 them

I don't know your light, but the only LED fixture i know that requires such a low hanging height is Migro Aray, 6-7 inches. 16cm for the standard version, 18cm for the Pro version. Power also needs to be adjusted to 25-30% for seedlings, 50% in veg and 100% in flower.
For autoflowers maybe even 75%-80% since they usually receive 18 hours of light but that depends from plant to plant.

However, even with my Migro i have to raise it higher because the top leaves are showing signs they don't like it too close, and they're not stretching properly. Better to go higher with increased intensity.

MIGRO does indicate their ARAY lights should be kept 6-7 inches above canopy, but even with PPFD testing by other users it's showing better spread and efficiency at about 10 inches.

All lights are different and IMO manufacturer specs are best to follow

Thanks guys.
I just politely tell him thanks for all the advice he has given me andhopefully will give, but he is simply wrong about there not being such a thing as light stress

kreikrei said:

Thanks guys.
I just politely tell him thanks for all the advice he has given me andhopefully will give, but he is simply wrong about there not being such a thing as light stress

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Definitely wrong about that. It really sounds like he's basing his knowledge off old LED/blurple tech.

I’d say don’t listen to another word from your friend and ask the questions you need answers for on here

As mentioned depends on light strength and quality also manufacturer's recommendations. They are usually accurate. If plants stretch lower light or increase power. If plants droop away from light, raise light or lower power. Plants will also show white or burnt leaf tips top down will also appear nitrogen or any other type of deficiency from the top down if light is too intense. Pics show fairly early light intensity, I attempted to run a ROI-e720 in a 4x4 3xs lol that's the last time I had even removed my inline fan and filter putting fan on top of tent to be able to raise light to the roof. Young plants do need less light however less light far away will make them stretch again depending on quality and power of led will determine how close light needs to be. I veg with 200 watts of fluorescent all but touching plants lesser quality light.

kreikrei said:

1. IMMEDIATELY lowers the leds/turns them up to 100% (They deliver MOREt than 100k lux this way)

2. So he goes away and I turn the light down and pull the up hahah. When he comes back, I put them in the spot he last left them LOL

3. I dont want to grow "his way"

4. What should I do?

Thanks.

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1. Tell him to stop adjusting your light.

2. Stop doing that. It's your grow and your light. Put it where it should be and leave it there.

3. Then don't.

4. Grow your plants. LST, nutrients, etc... do not require any expertise.

xtsho said:

1. Tell him to stop adjusting your light.

2. Stop doing that. It's your grow and your light. Put it where it should be and leave it there.

3. Then don't.

4. Grow your plants. LST, nutrients, etc... do not require any expertise.

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Thanks.
Its a bit hard because he has been right about everythinbg else and I am total beginner. But slowly educating myself by reading a book and forum debates.

He visisted 2 days ago and setup the light about 8 inches from top of plants at100% intensity.
Lux meter showed 100k on all plants.

I just couldnt ignore verything I have read on forums/blogs and today I pulled the light higher (about 20 inches above tpof plants) and regulated the LUX to about 35k

Current LEDs are a totally different animal from anything around 10 years ago, they are STRONG! Try your light at 50% and 2 feet as a starting point for seedlings.

3 yrs experience isnt that much in anything imo especially if the experience is a decade old

Bro it's your shit, who cares if he has been right so far or not. TELL HIM TO STOP FUCKIN WITH YOUR LIGHT! lol sorry for caps but dude has literally no right to adjust your shit if he didn't pay for it. Its cool to offer advice or tell you to move it down but not to do it his self. He needs to respect if you want to run the light higher (which is right btw)

bam0813 said:

3 yrs experience isnt that much in anything imo especially if the experience is a decade old

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Especially as it pertains to "technology"

bam0813 said:

3 yrs experience isnt that much in anything imo especially if the experience is a decade old

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TBH thats probably why he thinks the leds should be so close. The tech has come a LONGGGGG way in the time since he last grew. Dude needs to re educate himself on LED tech.

I will say this though. . ...

If your buddy adjusts the light again, just let it ride for at least 1-2 days; if your plants are not reacting poorly to it, then there "may" be some truth to what he's doing or saying. As stated, Shane from MIGRO does that and I have every reason to trust what he says. If the leaves taco or do any tiny little adverse thing, you can be like "LOOK FUCKER, STOP FUCKING W MY LIGHT"

PopAndSonGrows said:

I will say this though. . ...

If your buddy adjusts the light again, just let it ride for at least 1-2 days; if your plants are not reacting poorly to it, then there "may" be some truth to what he's doing or saying. As stated, Shane from MIGRO does that and I have every reason to trust what he says. If the leaves taco or do any tiny little adverse thing, you can be like "LOOK FUCKER, STOP FUCKING W MY LIGHT"

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I have heard about this Migro is it a yutube channel? I have heard he is a reputable source when it comes to masurments etc.

Is he growing cannabis using much more LUX than recommnded elsewhere? For example



Clones and seedlings: 5,000–7,000 lux
Vegetative growth: 15,000–50,000 lux
Flowering: 45,000–65,000 lux
Maximum recommended amount of light: 75,000 lux

That would mean he also surpasses these values?


AUTO FLOWER LED LIGHT INTENSITY
Recommended LED PPF/PAR Values / DLI Based on 20 hrs. of light.
Seedlings 150 - 200 umol / DLI 10.80 - 14.4 moles per day
Veg up to 9" 450 umol / DLI 32.40 moles per day
Early bloom 500 umol / DLI 36.00 moles per day
Mid bloom 650 umol / DLI 46.80 moles per day
Late bloom 750 umol / DLI 54.00 moles per day
Ripen 400 umol / DLI 28.80 moles per day