LED Light Intensity Chart Question

[SammyJankis]

I have a unbranded 240w LED light without dimmer and just mix of warm and cool light, nothing red or anything. And my plants are small and slow. I have a Spiderfarmer SE3000 on the way and will use it for my next run.
But I see their chart for what light intensity to use when. They are saying 30% all veg, sound weak, can I do 30% for 3 weeks and 50% for 3 weeks before switching to 12/12 and then working my way up to 100% during flower?
Also with autos will it be different? 30% seems low for photos, but then I can veg for longer (not that I want to), but 30% for autos seem ridiculous

 

[Listersmeghead]

I've got a SE3000 spider farmer, version 1 though. I don't know if yours is the newer model?
It's a really strong light. I've got an auto in 3rd week of flower and my light is on 75%. The plant is showing slight stress.

So the answer to your questions rely on a couple of factors.
What size tent..how high you hang the light and the general environment being right. Oh and plant health and strain.

All that aside, the se3000 grows some great plants. You'll love it.

I just use a cheap lux meter to set my light.
Seedling : 15,000 lux.
Veg : 20,000 - 50,000 lux.
Flower : 50,000 +

 

[SammyJankis]

I have the SE3000 300W LED.
My tent is 80x80cm (2.75'x2.75')

 

[Listersmeghead]

Yeah, that's the version 2 newer model. It's got different diodes than v1 but similar performance. Great light.

i use an 80×80 tent also with my se3000..here's a forbidden runtz auto I grew with it. Post in thread '3 auto plants' 3 auto plants
I was more than happy with it.

 

[Delps8]

I have a unbranded 240w LED light without dimmer and just mix of warm and cool light, nothing red or anything. And my plants are small and slow. I have a Spiderfarmer SE3000 on the way and will use it for my next run.
But I see their chart for what light intensity to use when. They are saying 30% all veg, sound weak, can I do 30% for 3 weeks and 50% for 3 weeks before switching to 12/12 and then working my way up to 100% during flower?
Also with autos will it be different? 30% seems low for photos, but then I can veg for longer (not that I want to), but 30% for autos seem ridiculous

Light manufacturers will tend to provide conservative advice because that reduces the chances that growers will damage their plants and call and complain.

Unless you have good reason to not follow their guidelines, they're usually pretty good. Having said that, the values for veg and early flower look to be more conservative than most.

You won't go wrong with those settings - you'll get a good crop. On the other hand, I would guess that you could increase yield significantly by spending $35 for a light meter and following the very simple rule of getting your plants up the the light saturation point as quickly as possible.

I was sold on that approach after about 12 months as a grower because the all research on the topic demonstrates that cannabis will thrive at extremely high levels of light and the plant yield and quality and crop yield and quality increase with the more light that you give it.

Check out my last few grow journals and you'll see how cannabis does under very high light conditions.

I don't know about autos vs photos in general but I know that cannabis has a "light saturation point" that's between 800 and 1000µmols and I've never seen an indication there's any difference.

I can say that the autos that I've grown (5 grows, 3 strains) were very happy at >= 900µmols but I never pushed them to go over 1100µmols. On the other hand, I've got a Chemdog photo grow going and it's been doing fine in the low 1100's.

 

[SammyJankis]

Light manufacturers will tend to provide conservative advice because that reduces the chances that growers will damage their plants and call and complain.

Unless you have good reason to not follow their guidelines, they're usually pretty good. Having said that, the values for veg and early flower look to be more conservative than most.

You won't go wrong with those settings - you'll get a good crop. On the other hand, I would guess that you could increase yield significantly by spending $35 for a light meter and following the very simple rule of getting your plants up the the light saturation point as quickly as possible.

I was sold on that approach after about 12 months as a grower because the all research on the topic demonstrates that cannabis will thrive at extremely high levels of light and the plant yield and quality and crop yield and quality increase with the more light that you give it.

Check out my last few grow journals and you'll see how cannabis does under very high light conditions.

I don't know about autos vs photos in general but I know that cannabis has a "light saturation point" that's between 800 and 1000µmols and I've never seen an indication there's any difference.

I can say that the autos that I've grown (5 grows, 3 strains) were very happy at >= 900µmols but I never pushed them to go over 1100µmols. On the other hand, I've got a Chemdog photo grow going and it's been doing fine in the low 1100's.

Thank you for a well written, easy to understand reply!!
I have now ordered a light meter and will adjust my light after that instead of the chart! Thank you, my man!

 

[Delps8]

Thank you for a well written, easy to understand reply!!
I have now ordered a light meter and will adjust my light after that instead of the chart! Thank you, my man!

You're very welcome.

If you're interested in the science behind it, the most digestible source of info are the YouTube videos by Dr. Bruce Bugbee. He touches on the basics in the videos that he has released and in videos where he is a guest (Dr. Growit and Shane from Migro). A secondary source is the videos from "DeBacco University" though, in his lighting videos, he primarily repackages what's in the Bugbee videos. DeBacco is the Cliff Notes, Bugbee is an actual university professor.

The other source is published research which codes into more detail but it's all very readable. I've got about a dozen papers on the topic and, if the mods allow it, I'd be happy to post the titles.

I've used a Uni-T light meter and have tested it with a few lights. Below is some data re. the factor used to convert lux to PAR. It varies due to the wavelengths of light in the light source. Your light has a well balanced spectrum so a factor of 0.015 will get you close enough. From there, you can "adjust fire".

Your light has a well balanced spectrum

 

[Tedmarx38]

This is a great thread. Maybe someone can help me. I ordered the SF2000 back in 2001, or so I thought, from Amazon for my 2x4x5’ tent. All along I’ve had problems with light and heat stress.

I just learned that Amazon actually shipped me the SF7000 by mistake back then and I hadn’t noticed the label until it was brought to my attention after I bought a second light. I actually received the sf2000 correctly this time which is nice.

Can anyone help me with proper intensity settings for the 7000 in this 2x4x5 tent? It’s overpowered but I don’t know how low I can set it and still have success in the flowering stage. Many thanks.

 

[Tedmarx38]

Light manufacturers will tend to provide conservative advice because that reduces the chances that growers will damage their plants and call and complain.

Unless you have good reason to not follow their guidelines, they're usually pretty good. Having said that, the values for veg and early flower look to be more conservative than most.

You won't go wrong with those settings - you'll get a good crop. On the other hand, I would guess that you could increase yield significantly by spending $35 for a light meter and following the very simple rule of getting your plants up the the light saturation point as quickly as possible.

I was sold on that approach after about 12 months as a grower because the all research on the topic demonstrates that cannabis will thrive at extremely high levels of light and the plant yield and quality and crop yield and quality increase with the more light that you give it.

Check out my last few grow journals and you'll see how cannabis does under very high light conditions.

I don't know about autos vs photos in general but I know that cannabis has a "light saturation point" that's between 800 and 1000µmols and I've never seen an indication there's any difference.

I can say that the autos that I've grown (5 grows, 3 strains) were very happy at >= 900µmols but I never pushed them to go over 1100µmols. On the other hand, I've got a Chemdog photo grow going and it's been doing fine in the low 1100's.

What’s a reasonably priced light meter option that you’d recommend?

 

[Delps8]

What’s a reasonably priced light meter option that you’d recommend?

The only lux meter I've used is the Uni-T that sells for about $35 at the 'Zon. I bought it because other growers have recommended it and because it was reviewed favorably my apparently honest reviewers.

I bought it last year and my use has been very limited. I have tested it against my Apogee and the readings have been consistent and are in line with what other sources on the internet report.

[time passes]

The model I bought in September of last year is a UNI-T UT383 and it's now available for $25.

 

[Delps8]

This is a great thread. Maybe someone can help me. I ordered the SF2000 back in 2001, or so I thought, from Amazon for my 2x4x5’ tent. All along I’ve had problems with light and heat stress.

I just learned that Amazon actually shipped me the SF7000 by mistake back then and I hadn’t noticed the label until it was brought to my attention after I bought a second light. I actually received the sf2000 correctly this time which is nice.

Can anyone help me with proper intensity settings for the 7000 in this 2x4x5 tent? It’s overpowered but I don’t know how low I can set it and still have success in the flowering stage. Many thanks.

Lucky you!

I checked the specs on that light and, yup, you'll have enough light!

Light is one part of the equation (out of nine). You may not be able to get to very high light levels - a way to maximize crop yield and quality - unless the other pieces of the puzzle are up to…par. I've seen grows where plants couldn't take more than 500µmols and it took a while to troubleshoot the cause. On the other hand, growers routinely use 1000µmols because the other factors that influence a grow have also been "done right". This is the light data for my current grow:

"79" is the standard deviation for PPFD and "3.4" is the standard deviation for DLI. Those numbers tell me that it's a very flat canopy.

The plant has quite a few buds and I've sampled 41 of them. The PPFD is averaging just over 900µmols because I've included the buds that are at the ends of the light bars and that are much further (vertically) from the light. At times, some of the buds have been > 1100 µmols and I have not seen any issues with excessive light. This is a non-CO2 enhanced environment.

Bugbee says "cannabis loves light" but I recently saw a comment that described it as cannabis is inefficient in terms of photosynthesis. I think of it as Bugbee sees it. Growers who have to justify spending $$ on a light, perhaps to their spouse, might justify their purchase think of it as an efficiency issue.

 

[Tedmarx38]

Thanks! Maybe you or someone else can help me with a question. On the sf7000, there are four light panels, two on one side of the folding board and two on the other side. They’re fed on each side by one power cord to the left and one to the right.

These cords screw into the frames and I loosened them, but I can’t see how to detach them as the cord stays intact even when loosened. The manuals are no help. Does anyone have a suggestion on how to do this? I’d like to render one of the two sides inactive by decoupling it from the power supply. Thanks!

 

[Tedmarx38]

UNI-T UT383

Thanks, just ordered the uni-t!

 

[Delps8]

Thanks! Maybe you or someone else can help me with a question. On the sf7000, there are four light panels, two on one side of the folding board and two on the other side. They’re fed on each side by one power cord to the left and one to the right.

These cords screw into the frames and I loosened them, but I can’t see how to detach them as the cord stays intact even when loosened. The manuals are no help. Does anyone have a suggestion on how to do this? I’d like to render one of the two sides inactive by decoupling it from the power supply. Thanks!

You're welcome and I would not modify the light.

An expression in my software community is "Lie down until that feeling goes away". Seriously.

The potential for saving electricity cost is minimal and the downsides are numerous and significant.

The first reason to not cut your light output in half is that you're going to need all of that light to get a top notch PPFD pattern. The SF7000 is a board light and it has the typical board light light cast — you've got a hot spot in the middle.

Compare the center area of the SF7000 against lights with unusually good light patterns (the Vipar XS 1500 Pro and the Spider SE7000 are standouts) and you'll see that the light drop off in the 2' x 4' region of the SF7000 compares very well when the hang height is at 18" or 24". That's not a knock on Spider, that's just how board lights generate a light pattern (check out an HLG if you want to see an "air fryer", though they did just release an updated Diablo that has reflectors which help get around this aspect of the board light design).

By shoe-horning this big light into your tent, you will have a very uniform PPFD map. Cutting light output by 50% is not going to improve your grow.

The second outcome of disabling ½ your light is that you will void the warranty.

Finally, the light may overheat and/or catch fire. That could be exciting, granted, but it would really muck up your grow.

 

[bluter]

These cords screw into the frames and I loosened them, but I can’t see how to detach them as the cord stays intact even when loosened. The manuals are no help. Does anyone have a suggestion on how to do this? I’d like to render one of the two sides inactive by decoupling it from the power supply. Thanks!

don't touch them.

they will be crossed over internally. you may only have one driver, depending on wiring it could require all the panels operational to be in balance.

if you have a dimming option use that to reduce intensity if you feel you need it, or raise the light.

 

[Tedmarx38]

You're welcome and I would not modify the light.

An expression in my software community is "Lie down until that feeling goes away". Seriously.

The potential for saving electricity cost is minimal and the downsides are numerous and significant.

The first reason to not cut your light output in half is that you're going to need all of that light to get a top notch PPFD pattern. The SF7000 is a board light and it has the typical board light light cast — you've got a hot spot in the middle.

Compare the center area of the SF7000 against lights with unusually good light patterns (the Vipar XS 1500 Pro and the Spider SE7000 are standouts) and you'll see that the light drop off in the 2' x 4' region of the SF7000 compares very well when the hang height is at 18" or 24". That's not a knock on Spider, that's just how board lights generate a light pattern (check out an HLG if you want to see an "air fryer", though they did just release an updated Diablo that has reflectors which help get around this aspect of the board light design).

By shoe-horning this big light into your tent, you will have a very uniform PPFD map. Cutting light output by 50% is not going to improve your grow.

The second outcome of disabling ½ your light is that you will void the warranty.

Finally, the light may overheat and/or catch fire. That could be exciting, granted, but it would really muck up your grow.

Thanks one again! Yeah you make great points with these much appreciated suggestions. I’ll sit tight and use my light meter to adjust accordingly once it gets here. Cheers.

 

[Tedmarx38]

don't touch them.

they will be crossed over internally. you may only have one driver, depending on wiring it could require all the panels operational to be in balance.

if you have a dimming option use that to reduce intensity if you feel you need it, or raise the light.

Sounds good, thanks. The one benefit of this undiscovered overpowered light is I’ve learned to manage heat and light stress. I often wondered if something unusual was going on, because all the suggestions I received on dimming when I’ve been operating on the assumption that I had a 200 W light never seemed to work.

 

[Tedmarx38]

I have the UT383 now and am a bit overwhelmed with all the terminology, symbols, conversions and so on being used online. Maybe I’m being too simplistic but after reading through various threads, it appears that this meter only measures brightness as in “Lux”, but has a button that does a one step conversion to foot candles.

The other types of measurements such as micromoles are just approximations via linear equations based on Lux, correct? Unless one has a fancy expensive meter? I hope it’s that simple.

If it helps, I’m using a sf2000 and sf7000, both from spider farmer, separately in two respective tents that are both 2x4. I see these figures referenced elsewhere for lux readings* but I’m curious as to whether it’s this simple given my situation: the sf7000 is overpowered for this size tent and I need to back it down with the dimmer vs manufacturers recos. I do wonder though if the spectrum coverage gets compromised by doing so.

*
Seedling : 15,000 lux.
Veg : 20,000 - 50,000 lux.
Flower : 50,000 +

Many thanks.

 

[farside05]

I have the UT383 now and am a bit overwhelmed with all the terminology, symbols, conversions and so on being used online. Maybe I’m being too simplistic but after reading through various threads, it appears that this meter only measures brightness as in “Lux”, but has a button that does a one step conversion to foot candles.

The other types of measurements such as micromoles are just approximations via linear equations based on Lux, correct? Unless one has a fancy expensive meter? I hope it’s that simple.

If it helps, I’m using a sf2000 and sf7000, both from spider farmer, separately in two respective tents that are both 2x4. I see these figures referenced elsewhere for lux readings* but I’m curious as to whether it’s this simple given my situation: the sf7000 is overpowered for this size tent and I need to back it down with the dimmer vs manufacturers recos. I do wonder though if the spectrum coverage gets compromised by doing so.

*
Seedling : 15,000 lux.
Veg : 20,000 - 50,000 lux.
Flower : 50,000 +

Many thanks.

When using a lux meter for cannabis, Use This As Your Guide (link).

 

[bluter]

The other types of measurements such as micromoles are just approximations via linear equations based on Lux, correct? Unless one has a fancy expensive meter? I hope it’s that simple.

not quite, but for most growers it's close enough. lux measures a whole bunch of stuff that the plant doesn't use, and a lot of what it does.

lux, par, ppfd are all interrelated but it's only the last one that zeros in on plant use.

If it helps, I’m using a sf2000 and sf7000, both from spider farmer, separately in two respective tents that are both 2x4. I see these figures referenced elsewhere for lux readings* but I’m curious as to whether it’s this simple given my situation: the sf7000 is overpowered for this size tent and I need to back it down with the dimmer vs manufacturers recos. I do wonder though if the spectrum coverage gets compromised by doing so.

it does. full spec white light leds contain many emitters at differing kelvin. some parts of the spectrum drop out earlier than others when dimming. blue runs out a little early.

it's not enough to fret over generally, by 50% most stuff is all present, by 75% it's all there and you are only working with intensity level. dedicated emitters from 4000k and above won't lose nearly as much either. they will be present on most full spec rigs.

i run a mix of 3000k and 3500k which is a dedicated flower bias - much the way an old hps used to work. it's still ok in veg, but i supplement it with a couple hours of 5050 smd burples each day to make sure it gets enough blue spectrum.

because my emitters are biased to the red spectrum, i can really notice how much less blue they carry when dimmed.