SpiderFarmer SE3000 PPFD Chart, Accurate?

  • Thread starter Dothraki
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Dothraki

Dothraki

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Hey all,

I am getting ready to start my first grow, 3x3 tent, LED light (SF SE3000) with dimmer switch.

Learning about PPFD, if the chart provided by the manufacturer is accurate (with obvious error margins between productions), can I use this to calculate PPFD at each distance or is there a curve that’s impossible to know?

I’ve heard these charts are very inaccurate. What’s the story with them?
FA7BCD8F 53DD 4DF9 A8F0 6A0BFD071F62
 
Dothraki

Dothraki

811
93
I’m trying to get an idea of what height at each growing phase from seed I would start with. Keeping in mind this was tested in a grow tent so readings are higher than a 3rd party test.
 
growsince79

growsince79

6,903
313
Hey all,

I am getting ready to start my first grow, 3x3 tent, LED light (SF SE3000) with dimmer switch.

Learning about PPFD, if the chart provided by the manufacturer is accurate (with obvious error margins between productions), can I use this to calculate PPFD at each distance or is there a curve that’s impossible to know?

I’ve heard these charts are very inaccurate. What’s the story with them? View attachment 1182372
Looks pretty suspect to me. I would think 2" would make more difference.
 
Dothraki

Dothraki

811
93
Looks pretty suspect to me. I would think 2" would make more difference.
It’s also kinda funny they only showed a specific 2“ area for the reading. I’m assuming that drop off is horrible after 10” and that’s why they didn’t give us 12” or 18” or 24”.
 
growsince79

growsince79

6,903
313
It’s also kinda funny they only showed a specific 2“ area for the reading. I’m assuming that drop off is horrible after 10” and that’s why they didn’t give us 12” or 18” or 24”.
They also say 6-10" in flower. With the PAR they claim would kill anything I try to grow. 700ppfd is more than enough for my soil grows.
 
Dothraki

Dothraki

811
93
They also say 6-10" in flower. With the PAR they claim would kill anything I try to grow. 700ppfd is more than enough for my soil grows.
Damn...lol. Yeah maybe I need to find someone that’s used this light and get some basic ideas for distance because obviously the company is either A. Smearing the facts, or B. Just flat out lying
 
Dothraki

Dothraki

811
93
Based off this chart does anyone have an idea of percentage and distance you would start with for once the seed pops, seedling phase, veg, flower? Like 30“/25% first two weeks, etc,
 
PipeCarver

PipeCarver

2,724
263
Based off this chart does anyone have an idea of percentage and distance you would start with for once the seed pops, seedling phase, veg, flower? Like 30“/25% first two weeks, etc,
I just got this light set up yesterday. I have it 19" from a Bubble Bomb that was about 6 weeks old before I flipped her 5 days ago. I get a lux reading of around 30,000. I was keeping her around 24" from a SF1000 I started her under giving me a lux 8,000 [email protected]% ..I moved her up to 20,000 lux before I flipped her
 
100 6116
100 5878
Dothraki

Dothraki

811
93
What if I did 10” @ 25% for seedling, 10” @ 60% Veg, and 100% for flowering? Based on the chart I posted?
 
Dothraki

Dothraki

811
93
1200ppfd would kill anything I try to grow.
I think they exaggerate the numbers...but better to be safe. I would try raising it to 12” or so... but I‘m not sure if the method of estimating I’m using is right.
 
Dothraki

Dothraki

811
93
1200ppfd would kill anything I try to grow.
One thing I’m not understanding is distance vs intensity. So if a light was reading, let’s say 500 PAR @ 20”, and you bring it closer to the plant at 10” but dimming it to get the same 500 PAR...would it still be the same result on the plant? And...is there a way to calculate the PAR by using a percentage drop off per inch? Or does that have to be done manually with readings at each inch?
 
growsince79

growsince79

6,903
313
One thing I’m not understanding is distance vs intensity. So if a light was reading, let’s say 500 PAR @ 20”, and you bring it closer to the plant at 10” but dimming it to get the same 500 PAR...would it still be the same result on the plant? And...is there a way to calculate the PAR by using a percentage drop off per inch? Or does that have to be done manually with readings at each inch?
My lights don't have dimmers so idk.
 
dbrzz

dbrzz

103
43
Hey all,

I am getting ready to start my first grow, 3x3 tent, LED light (SF SE3000) with dimmer switch.

Learning about PPFD, if the chart provided by the manufacturer is accurate (with obvious error margins between productions), can I use this to calculate PPFD at each distance or is there a curve that’s impossible to know?

I’ve heard these charts are very inaccurate. What’s the story with them? View attachment 1182372
I have a sf4000, I have a 4x4. This light @ 100% output, has the best growth rate @ 24 inches. This height has optimum photon spread across the space. The edge ppfd is approx. 507 and the center is 850.

 
tucume66

tucume66

16
3
One thing I’m not understanding is distance vs intensity. So if a light was reading, let’s say 500 PAR @ 20”, and you bring it closer to the plant at 10” but dimming it to get the same 500 PAR...would it still be the same result on the plant? And...is there a way to calculate the PAR by using a percentage drop off per inch? Or does that have to be done manually with readings at each inch?

Hello. I've been reading your thread and may I just interject that the formula for calculating what your PAR/PPFD at any given distance change is what is known as the Inverse Square Law applicable to all forms of light, visible and invisible. Hope this helps. Intensity 1 over Intensity 2 = Distance 2 (squared) over Distance 1 (squared) Just set up the equation as I have it here, square your Distances 1 & 2 and then cross-multiply. Results will demonstrate mathematically that when you reduce the distance by 1/2 you increase the light intensity value X 4 Conversely if you double the new distance from the light source you will end up with 1/4 the light intensity. You can review the Inverse Square Law online and get a working formula where you can plug in your own values.

 
tucume66

tucume66

16
3
My lights don't have dimmers so idk.
Hello. I've been reading your thread and may I just interject that the formula for calculating what your PAR/PPFD at any given distance change is what is known as the Inverse Square Law applicable to all forms of light, visible and invisible. Hope this helps. Intensity 1 over Intensity 2 = Distance 2 (squared) over Distance 1 (squared) Just set up the equation as I have it here, square your Distances 1 & 2 and then cross-multiply. Results will demonstrate mathematically that when you reduce the distance by 1/2 you increase the light intensity value X 4 Conversely if you double the new distance from the light source you will end up with 1/4 the light intensity. You can review the Inverse Square Law online and get a working formula where you can plug in your own values.

Dr. Bruce Bugbee who heads the Agricultural program at Utah University and is President of Apogee Instruments has many videos on Youtube that you may want to watch - here is one that relates to PAR/PPFD, etc.
 

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