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Please help me understand this umol's/par

vyserage

Well-Known Member
So from what i have read, the ideal range is 700 umols? Or atleast they can handle up to 1500-2000 but 700 gave prety much the same results and less consumption of energy.

So i have 2 of these lights in a 48x48x96 tent, currently hanging 15' above canopy. Am i good? Too intense for that heighth? Do i need more red lights in flowering? I saw a comment on the product saying "G8" led light was a good extra for flowering, true? (Damn they expensive! A bit more than each grow light im talking about!) I noticed the G8 is good for 10 square feet, isnt that really small of a space? I'd need like 4 of these to cover the whole tent, thats bs!

Thanks in advance guys ^_^ I only need to know if these lights im using are good for my 4x4 tent or if im lacking in anything (to do with light).

vipar.png
 

Walter melon

New Member
Re: Plz help me understand this umol's/par

I personally run a 3x3x4 tent with 2 600w LEDs (360 something w at the wall.) 1 viparspectra, and one bloomspect. I'm leaning towards the bloomspect being the better light. Both lights were around $100 each. My ppfd as advertised is around 1400. The minimum to get any kind of growth is 500 umols. 700 is WAY TOO LOW for any kind of flowering room. You want as close to 1500 as you can get, trust me I tried with 1000, it didn't go well.
As far as par goes, you either have it or you don't. Par is the light waves your plant needs to live. It's there or it's not. It's really that simple.
 

vyserage

Well-Known Member
Re: Plz help me understand this umol's/par

I personally run a 3x3x4 tent with 2 600w LEDs (360 something w at the wall.) 1 viparspectra, and one bloomspect. I'm leaning towards the bloomspect being the better light. Both lights were around $100 each. My ppfd as advertised is around 1400. The minimum to get any kind of growth is 500 umols. 700 is WAY TOO LOW for any kind of flowering room. You want as close to 1500 as you can get, trust me I tried with 1000, it didn't go well.
As far as par goes, you either have it or you don't. Par is the light waves your plant needs to live. It's there or it's not. It's really that simple.

So going by my pic above, with 2 lights side by side im getting 1050 umol's in a 1x1 area correct?
 

Walter melon

New Member
Re: Plz help me understand this umol's/par

That's at a height of 24". You can get that light a lot closer than that to get the ppfd up. There's a way to calculate what it would be at 16". At 16" I think it would be around 900 or 1100? Each. Maybe much higher, the inverse square law formula is out there somewhere. The ppfd would also be a bit higher with the overlap of the two lights. I run both of mine at 26" because if they were lower the ppfd would be well over 1500 at 16".
 

PurpleGunRack

Well-Known Member
Re: Plz help me understand this umol's/par

So from what i have read, the ideal range is 700 umols? Or atleast they can handle up to 1500-2000 but 700 gave prety much the same results and less consumption of energy.

So i have 2 of these lights in a 48x48x96 tent, currently hanging 15' above canopy. Am i good? Too intense for that heighth? Do i need more red lights in flowering? I saw a comment on the product saying "G8" led light was a good extra for flowering, true? (Damn they expensive! A bit more than each grow light im talking about!) I noticed the G8 is good for 10 square feet, isnt that really small of a space? I'd need like 4 of these to cover the whole tent, thats bs!

Thanks in advance guys ^_^ I only need to know if these lights im using are good for my 4x4 tent or if im lacking in anything (to do with light).

PAR is the lightwaves between 400 nanometer and 700 nanometer, this is just the range of lightwaves plants use for photosynthesis.

PAR is measured in PPFD (micromoles per second)

You want 800-1000 PPFD everywhere in your grow room, not just under the center of the lamp, anything above 1200 and you need CO2 or you're just wasting the extra energy, with CO2 going above 1500 is where it starts to become minimal what you get for the extra energy put in. These numbers are for getting the optimal light saturation and you can easily grow with a lot less light and have great results.

It's a bit useless when they only measure at 24'', because we have our light a lot closer than that, good LED sellers provide PPFD readings from at least 12'', 18'' and 24'' The V600 somewhat effectively covers 2x2, so for 4x4 you need 4 of them, but you can grow with 2, just remember to rotate your plants.

15'' is fine, just stay above ~10'' in flower to avoid trichomes evaporating.



The minimum to get any kind of growth is 500 umols. 700 is WAY TOO LOW for any kind of flowering room. You want as close to 1500 as you can get, trust me I tried with 1000, it didn't go well.
As far as par goes, you either have it or you don't. Par is the light waves your plant needs to live. It's there or it's not. It's really that simple.

Sorry to be blunt, but this is just not true.


So going by my pic above, with 2 lights side by side im getting 1050 umol's in a 1x1 area correct?

No, PPFD is not cumulative like that, and you have to look at the PPFD readings across the entire area, not just in the center of the footprint.

If you have the lamps next to each other you can roughly add the edge readings, so if you have 2 of these @ 24'' in a 2x4 area you get almost 500 PPFD in the 2x2 line where the footprint of the 2 lamps meet.
 

Walter melon

New Member
Re: Plz help me understand this umol's/par

The university of Mississippi's own marijuana paper is where I got my ppfd numbers. I can also site them if you'd like. Can you site your papers with a scientific study?
 

Walter melon

New Member
Re: Plz help me understand this umol's/par

You are correct about the chart with both lights. I always assume everyone runs how I do. 3x3 with 2 600w panels side by side mine would double at the center. Space between the lights would need to be taken into account. You would have to space yours out a bit. Mine run almost the entire perimeter of my tent.
 

vyserage

Well-Known Member
Re: Plz help me understand this umol's/par

Hmm it's hard for me to decide if I want to get another light to put in the middle like say maybe 1200 watt, or add a g8 in middle during flower. My issue with that is it only covers a 10 square feet which is ridiculously small of an area for price.
I guess if I really want to get technical about it i'm going to need to purchase the led light detection thing, I forget what it's called. Then I can figure out if I need to get more light in there or around the sides or corners. So far my highest yielding plant has been 74 grams which isn't great but the others were 55 or below. Must also factor in that it was my first grow and the one that gave 74 was my experimental plant for heavy defoliation. This current growth should be interesting to see the results now that I am applying the heavy d foliation to all six plants.
Next grow in 2 and 1/2 months is hydro! Rdwc, I've already got the equipment :)
 

PurpleGunRack

Well-Known Member
Re: Plz help me understand this umol's/par

The university of Mississippi's own marijuana paper is where I got my ppfd numbers. I can also site them if you'd like. Can you site your papers with a scientific study?

You said you tried to grow under 1000 PPFD and it couldn't be done.... More than half the people here succesfully grow with under 1000 PPFD, and I've done many succesful grows with PPFD of 500-700.

If you can't grow flowers under 1000 PPFD, something else is very wrong.

Even though you have a lot of ligth(and draw) in your area, you're most likely under 1000 PPFD at the corners and edges, the number directly under the lamp is not the only one to look at.

I read the study, though interesting it's based on vegging plants for a short duration of PPFD exposure at different temperatures and CO2 levels.
If you read about the full grow testing done with flowering plants, you'll find that going above 1200 PPFD without CO2 enhancement will give you a marginal return in yield and cannabinoids.
No where in this study does it say that you can't flower with under a certain level of PPFD, and how could it, not a single flower was present in the study.

I don't want to search for all the studies I've read in the past, but you should try looking at RUI, LEDgardener and ChilLED and learn a little more about light and photosynthesis.
 

KingJoe83

Grow Journal of the Month: July 2017
Plz help me understand this umol's/par

I'll need to read this thread in abit see if I can learn about umols more myself

I think once you hit 1800 umols you need to co2 after that if not mistaken?
 

Walter melon

New Member
Re: Plz help me understand this umol's/par

No where in my statement did I say it can't be done. I said it wasn't the results I was looking for. I'm also one that would rather get my science from something peer reviewed instead of YouTube, respectfully. Even with a marginal return on my $100 investment, if I get the results I'm looking for I'm a happy guy now. Again YouTube is far from my source of science, and will stick to peer reviewed items. I can find more, that was just the first Google result.
 

PurpleGunRack

Well-Known Member
Re: Plz help me understand this umol's/par

Hmm it's hard for me to decide if I want to get another light to put in the middle like say maybe 1200 watt, or add a g8 in middle during flower. My issue with that is it only covers a 10 square feet which is ridiculously small of an area for price.
I guess if I really want to get technical about it i'm going to need to purchase the led light detection thing, I forget what it's called. Then I can figure out if I need to get more light in there or around the sides or corners. So far my highest yielding plant has been 74 grams which isn't great but the others were 55 or below. Must also factor in that it was my first grow and the one that gave 74 was my experimental plant for heavy defoliation. This current growth should be interesting to see the results now that I am applying the heavy d foliation to all six plants.
Next grow in 2 and 1/2 months is hydro! Rdwc, I've already got the equipment :)

A good enough PAR meter is +$500, so you might as well spend that on more light ;)

Yields depend on many other factors than the light; pot size, veg time, temperature, humidity, strain, nutrients, gardening skills etc.

Just to make it clear, ''1200w'' LED lamp doesn't really mean anything since it's just a number the seller puts on it to make it more sellable, and it has nothing to do with the actual draw power , or how much of it is converted to light. I've seen ''1200w'' draw from 150w to 800w.

I can point you in direction of superior light if you're willing to do a little DIY, do you have a budget for light?
 

vyserage

Well-Known Member
Re: Plz help me understand this umol's/par

A good enough PAR meter is +$500, so you might as well spend that on more light ;)

Yields depend on many other factors than the light; pot size, veg time, temperature, humidity, strain, nutrients, gardening skills etc.

Just to make it clear, ''1200w'' LED lamp doesn't really mean anything since it's just a number the seller puts on it to make it more sellable, and it has nothing to do with the actual draw power , or how much of it is converted to light. I've seen ''1200w'' draw from 150w to 800w.

I can point you in direction of superior light if you're willing to do a little DIY, do you have a budget for light?

i try to use money i've earned from my bud to invest into upgrades, so its very slow going atm. I got my tax return and purchased about $400 for supplies/hydro system, im tapped out for now but i most definitely do want to know of this superior light! I want to perfect every inch of my grow to ensure no matter where my plant is growing inside, its getting excellent light. Lets hear what you have!
 

PurpleGunRack

Well-Known Member
Re: Plz help me understand this umol's/par

The bloomspect 600 at 18" puts off around 1300 ppfd according to the advertised values and costs around $100.

You have to have a full chart to know anything for sure, 1300 PPFD dead center under the light, and my guesstimate is that it drops to about half that at the 2x2 edge.


No where in my statement did I say it can't be done. I said it wasn't the results I was looking for. I'm also one that would rather get my science from something peer reviewed instead of YouTube, respectfully. Even with a marginal return on my $100 investment, if I get the results I'm looking for I'm a happy guy now. Again YouTube is far from my source of science, and will stick to peer reviewed items. I can find more, that was just the first Google result.

Well, what do you call this:

The minimum to get any kind of growth is 500 umols. 700 is WAY TOO LOW for any kind of flowering room. You want as close to 1500 as you can get, trust me I tried with 1000, it didn't go well.


Never said anything about youtube, I'm talking about reading stuff from people like Growmau5 and LEDGardener.

Try looking around the international cannabis communities and you'll quickly find the stated PPFD levels in my post above being recommended again and again.
 

PurpleGunRack

Well-Known Member
Re: Plz help me understand this umol's/par

i try to use money i've earned from my bud to invest into upgrades, so its very slow going atm. I got my tax return and purchased about $400 for supplies/hydro system, im tapped out for now but i most definitely do want to know of this superior light! I want to perfect every inch of my grow to ensure no matter where my plant is growing inside, its getting excellent light. Lets hear what you have!

If you're on a tight budget getting HID is the way to go, you can even find used reflectors and ballasts and just have to spring for a new bulb.

If you're looking for the best the market has to offer at the moment you have to do a DIY build(or kit assembly) with strips/boards using the Samsung LM561C diode or the new Samsung LM301B diode. If you want to learn more about DIY, follow the link in my signature ;)
 

GodOfPot

Well-Known Member
Re: Plz help me understand this umol's/par

The bloomspect 600 at 18" puts off around 1300 ppfd according to the advertised values and costs around $100.

Wouldn't put much money on these "advertised values", thing is with 100's of different companies popping up and disappearing all the time, there's really no one holding them accountable to what they advertise on Amazon or E-Bay

I've seen some of these cheap LEDs come in under half of the advertised PPFD values before, so don't believe everything they advertise to you.

Also, didn't the source you cited come from the internet too? PGR knows his stuff, active helper in the "Grow Lighting" sub forum, pretty knowledgeable in lighting, he's only trying to help you get a better understanding :Namaste:
 

Walter melon

New Member
You're kidding right? The paper I sited came off of the internet? That's a peer reviewed study... You can't tell me a helper in the lighting section of a forum, has a better understanding, equipment, resources, and history in botany than a federally funded government sanctioned op that's been going for many, many years This is a joke right? Even with a peer reviewed scientific paper in front of us, we still believe it's wrong? That's slightly impressive.
 
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