Am i overthinking the height of my light?

[Homegrown81]

Ok so I've read so many threads and articles and watched videos about this but I still have a question and could just quite possibly be way over thinking things. Now I know there is no set height for lights as to the copious amount of variables that come into play i.e. kind of light, size,wattage, size of grow room, individual strains etc, but on average most people seem to say 16-24" flower, 24-30" veg and 30-36" seedling..on average. On top of that people seem to agree on lowering your light roughly 5% per week. So for someone that cant dial in a strength % and has to raise and lower their lights, am I really lowering the light so much as the plant naturally grows up toward the light? Currently my light is 42" above seedlings and they seem to being doing well and not stretching too much, 36" seemed too much for them. So let's say I follow that 5% rule. That means next week I would technically by those standards lower the light to 40". But let's say by next week my plants have grown 2 inches making them 40" from the light. Do I still lower the light or does it just come down to experimentation and getting a feel for it? Thanks in advance to anyone who understands my ramble. Lol

 

[BigCube]

It changes from fixture to fixture.

Grab yourself a lux meter, makes life easier if you have an android phone, you can download free lux meter apps.
If you have an iPhone dont bother, they don't work due to cheap parts and bad design. You an also get them for cheap on Amazon.

In veg you want 40k to 60k lux.
Flower you want 70k to 90k lux.

Hope this helps.

 

[Milson]

Ok so I've read so many threads and articles and watched videos about this but I still have a question and could just quite possibly be way over thinking things. Now I know there is no set height for lights as to the copious amount of variables that come into play i.e. kind of light, size,wattage, size of grow room, individual strains etc, but on average most people seem to say 16-24" flower, 24-30" veg and 30-36" seedling..on average. On top of that people seem to agree on lowering your light roughly 5% per week. So for someone that cant dial in a strength % and has to raise and lower their lights, am I really lowering the light so much as the plant naturally grows up toward the light? Currently my light is 42" above seedlings and they seem to being doing well and not stretching too much, 36" seemed too much for them. So let's say I follow that 5% rule. That means next week I would technically by those standards lower the light to 40". But let's say by next week my plants have grown 2 inches making them 40" from the light. Do I still lower the light or does it just come down to experimentation and getting a feel for it? Thanks in advance to anyone who understands my ramble. Lol

All heights are relative to canopy. Yes, it's common to mess with it a good bit. The recommendation to lower gradually is to avoid frying young plants.

Ultimately, it comes down to feel, but starting w ranges helps.

 

[CF89]

Damn. That’s far. My 2000w led (390w actual draw) is like 20” from my 3 week old plants. Thinking of going closer with those lux numbers mentioned above

 

[Milson]

Damn. That’s far. My 2000w led (390w actual draw) is like 20” from my 3 week old plants. Thinking of going closer with those lux numbers mentioned above

DO NOT USE LUX FOR BLURPLE

 

[Milson]

DO NOT USE LUX FOR BLURPLE

Sorry. Blurple spectrum will confuse a lux meter and will not be a good approximation of ppfd, which is what really matters.

 

[CF89]

DO NOT USE LUX FOR BLURPLE

oops. Good to know.
Either way. I don’t think my plants have ever seen light burn. Even if they do see a little, it’s not the end of the world is it?? Just raise the light up a tad and consider that the sweet spot. Not too high but not too low?

 

[Milson]

oops. Good to know.
Either way. I don’t think my plants have ever seen light burn. Even if they do see a little, it’s not the end of the world is it?? Just raise the light up a tad and consider that the sweet spot. Not too high but not too low?

Sorry mate I'm a bit baked and your post literally startled me lol.

It's kind of hard to recognize stunting due to excess light. I know because I thought the same as you lol. Then I stunted my babies a bit. Soooo my recommendation is actually to either find a reliable way to measure or tread lightly and mostly follow recommendations.

But no, not the end of the world if you catch it earlyish.

 

[CF89]

Ah good to know. I didn’t realize that too much would actually stunt them.

 

[BigCube]

Damn. That’s far. My 2000w led (390w actual draw) is like 20” from my 3 week old plants. Thinking of going closer with those lux numbers mentioned above

Oof you cant use lux for burple light.

Burple light is a throw back from years ago when white LEDs wernt good enough for growing. They made up for it by using Red and blue LEDs (used to be more efficient than white leds), and they also assumed that red and blue were all that was needed.

We know now, that plants absolutely use all colors of light. We know now that full spectrum (white) light is the best light to use.

I wonder why in the last 3 or 4 years, people have been buying burple LEDs. Since they are inferior in every way now.

If you are using burple, the only real way to measure is using a Par meter.

 

[AnonGrow420]

no more than 16 inches from the plant no less than 12 inches from them them

 

[CF89]

Oof you cant use lux for burple light.

Burple light is a throw back from years ago when white LEDs wernt good enough for growing. They made up for it by using Red and blue LEDs (used to be more efficient than white leds), and they also assumed that red and blue were all that was needed.

We know now, that plants absolutely use all colors of light. We know now that full spectrum (white) light is the best light to use.

I wonder why in the last 3 or 4 years, people have been buying burple LEDs. Since they are inferior in every way now.

If you are using burple, the only real way to measure is using a Par meter.

so are you saying some LED lights are white? and those are the good LEDs?

basically any LED that makes purple is inferior?

 

[Milson]

so are you saying some LED lights are white? and those are the good LEDs?

basically any LED that makes purple is inferior?

I think that is what he is saying. I also think that is a vast oversimplification. At this point it appears most manufacturers are moving to full-spectrum. That does not make blurples useless, as plenty of people who have grown good pot from them can attest.

 

[congolaw]

so are you saying some LED lights are white? and those are the good LEDs?

basically any LED that makes purple is inferior?

Yes exactly what he is saying, as it is only blue and red frequencies I.e. limited. Plant and light research has shown all spectrums/frequencies are beneficial to plants and therefore LED has advanced beyond using only two, blue and red.

 

[BigCube]

I think that is what he is saying. I also think that is a vast oversimplification. At this point it appears most manufacturers are moving to full-spectrum. That does not make blurples useless, as plenty of people who have grown good pot from them can attest.

Never said they were useless. Just inferior. I didn't say that any led that makes purple is inferior. I said BURPLE LEDs. RED and BLUE. I dont know how you managed to put those words in my mouth when I said red and blue, not "any purple light"

A normal while led fixture with a few red and uv lights will be purple in color.....

Are you just playing devil's advocate?
Cause if not, I suggest reading up on the subject.

 

[BigCube]

I realized I just sounded a bit harsh there. My apologies.

It's just that I try to word things so that they wont be taken wrong or mistaken.
It bothers me a bit when I fail to communicate to others clearly.

A basic crash course on light may help to clear things up. I started this thread a while back where I show what light is, how it works and what we can do with it.

Understanding light.

Just a short disclaimer here, I am not an expert. I've done my own research, I will show my sources and I am willing to be corrected. I will try my hardest to keep my bias out of the equation as best I can. Light a small portion of the electromagnetic radiation spectrum...

www.thcfarmer.com

 

[revfunk]

Honestly, it's not opinion. PAR/LUX can easily be measured and lights adjusted accordingly.

 

[Milson]

Never said they were useless. Just inferior. I didn't say that any led that makes purple is inferior. I said BURPLE LEDs. RED and BLUE. I dont know how you managed to put those words in my mouth when I said red and blue, not "any purple light"

A normal while led fixture with a few red and uv lights will be purple in color.....

Are you just playing devil's advocate?
Cause if not, I suggest reading up on the subject.

Fair enough. I have just seen a couple instances of people heavily shitting on someone's buying decision re: blurple and I feel bad about that. Not what I would buy, but there are plenty that are fine.

And yes, there are many good resources on light out there. I am particularly interested in the role green and far red play in canopy penetration and am experimenting with an additional 100 diodes of far red spectrum toward that effect.

 

[Homegrown81]

Well I seem to have started quite the debate lol sorry. It's my first indoor grow and I'm sure over time as I learn I'll be adding and or swapping out equipment over time. To give some context, here are the specs of the light I currently have and my setup which is 2'x2'. Oh and the light is 1200w(213w actual).

 

[BigCube]

Burple lights work, for sure. They just arent optimal. I try not to bash people for their choice of light. I try to inform them. Hopefully if the light is new they can still return it.

Nothing wrong with using them, just trying to inform ppls, specially when it comes to spending your money