recommended ppfd range?

[sunny747]

Siting here studying COBs

What ppfd should I be looking for in a setup? Considering I normally Keep small 2ft-3ft plants and uniform canopy.. LST, Scrog, etc....


Is 700 sufficient or should I be closer to 1200?

At what point are there diminishing returns?

Thx

 

[sunny747]

Oh, I found some info..

Growmau5 demonstrates that at over 1000 ppfd without using co2 then you are sort of wasting power.

600 ppfd to 800 ppfd would seem to be a decent range for a hobbyist or small personal grow. Assuming you have uniform coverage..

 

[sunny747]

 

[CobKits]

lower ppfd = higher gpw

 

[sunny747]

lower ppfd = higher gpw

Thanks for the response..

Would you explain that please?

As long as I have you on here.. (I've been reading a bunch of your posts What's the max watts you can run a COB at assuming you're not trying to burn it up? It seems to me that 100 watts is sort of understood and that most people run them at 50-80 watts each..

 

[CobKits]

Thanks for the response..

Would you explain that please?

diminishing returns as stated in growmau5's video. the higher you go, every ppfd you add yields less.

you may yield more per square foot, but you'll yield less per watt if you push it above 800

As long as I have you on here.. (I've been reading a bunch of your posts What's the max watts you can run a COB at assuming you're not trying to burn it up? It seems to me that 100 watts is sort of understood and that most people run them at 50-80 watts each..

depends on the cob but can be as high as 500+

 

[wietefras]

lower ppfd = higher gpw

and higher ppfd = higher g/m2. So it's a compromise, but between 600 and 800PPFD sounds reasonable.

What's the max watts you can run a COB at assuming you're not trying to burn it up? It seems to me that 100 watts is sort of understood and that most people run them at 50-80 watts each..

You should not look at maximum watts, but look for the wattage per COB were it's still as efficient as you would like. I tend to aim at something between 2.2 and 2.3 umol/s/W. That means to use the CXB3070 at 49W, the CXB3590 at 61.5W, the CLU048-1212 at 37W up to the CLU058-1825C4 at 109W. The Citizen COBs can cost about half as much to produce the same amount of light as the Cree COBs.

If your electricity is cheap or you want to pay less upfront you can drive them harder or if you want to use less electricity drive them softer.

 

[sixstring2112]

Idk where the hell you would even take the readings lol.im under the impression that an average of 500ppfd is pretty darn nizzle


650 ooooooomoles at the tops and about 300ppfd at the bottom 12 inches depending on how and where i hold the meter.
No co2,canopy temps 78f and r/h stays a constant 35 to 40% day and night,might bump 50% rh at night before the dehuy kicks on

 

[frica]

Siting here studying COBs

What ppfd should I be looking for in a setup? Considering I normally Keep small 2ft-3ft plants and uniform canopy.. LST, Scrog, etc....


Is 700 sufficient or should I be closer to 1200?

At what point are there diminishing returns?

Thx

Diminishing returns already start at about 600 but only become major around 800/900.

But anything between 600-900 is fine.
Going than higher than 900 means you will use a lot of energy for only slightly higher yields.

500 should work too.

 

[giantsfan24]

So when talking about ppfd, we're in a balancing act between efficiency and overall harvest weight is what I'm getting. Not that anything over 900 and higher ppfd would be bad for the plants just not as efficient in terms of gpw?

 

[captainmorgan]

I've done 2 GPW with scogs at 530 PPFD and do well with 700 PPFD with 3' to 3.5' tall natural plants, 1.4-1.5 GPW.

 

[sunny747]

So when talking about ppfd, we're in a balancing act between efficiency and overall harvest weight is what I'm getting. Not that anything over 900 and higher ppfd would be bad for the plants just not as efficient in terms of gpw?

Unless you add Co2... Then it's a different scale. But yes, you have the idea correct.

 

[RuRu.The.Half.Elf]

ooooooomoles

ooooooomoles

ooooooomoles

I forgot how funny that was.

 

[sunny747]

and higher ppfd = higher g/m2. So it's a compromise, but between 600 and 800PPFD sounds reasonable.

You should not look at maximum watts, but look for the wattage per COB were it's still as efficient as you would like. I tend to aim at something between 2.2 and 2.3 umol/s/W. That means to use the CXB3070 at 49W, the CXB3590 at 61.5W, the CLU048-1212 at 37W up to the CLU058-1825C4 at 109W. The Citizen COBs can cost about half as much to produce the same amount of light as the Cree COBs.

If your electricity is cheap or you want to pay less upfront you can drive them harder or if you want to use less electricity drive them softer.

Can we discuss this further?

How do we find the data for Umols per watt?

Let's take a look at some citi cobs since they seem to be the best value and I think we will see more people gravitating towards them..

I notice that the newer lights have high voltage as compared to the 36v cree and vero..

 

[frica]

So when talking about ppfd, we're in a balancing act between efficiency and overall harvest weight is what I'm getting. Not that anything over 900 and higher ppfd would be bad for the plants just not as efficient in terms of gpw?

It depends if you're limited by space, or power usage

A commercial grower would probably want to maximize earnings per square meter while somebody who grows for himself and sometimes to share a bit with friends doesn't need a gigantic amount of yield.

If you're growing for yourself, even a cheap 150w ebay mars growpanel in a 2 by 2 foot growbox should yield more than you consume alone* unless you're a very high level consumer.
Commercial growers on the other hand want to grow as much as they can on their space because rent is expensive, more expensive than electricity.

*Even autoflowers should yield more than enough for a single man.

 

[Participant]

500 ppfd?

So that means I am way over powered with 400w Vero framework in my 3x3?

Timber rates it at 1200 ppfd @ 18"

Electricity rates is very high. Should I dim it?

 

[frica]

500 ppfd?

So that means I am way over powered with 400w Vero framework in my 3x3?

Timber rates it at 1200 ppfd @ 18"

Electricity rates is very high. Should I dim it?

You can easily dim it to 800 ppfd and yield will be only a little smaller.
At 600 ppfd yield will be only be 20% smaller or so, give or take.

Wouldn't go below 500.
But you can easily dim it if electricity price is a concern.

 

[sunny747]

It depends if you're limited by space, or power usage

A commercial grower would probably want to maximize earnings per square meter while somebody who grows for himself and sometimes to share a bit with friends doesn't need a gigantic amount of yield.

If you're growing for yourself, even a cheap 150w ebay mars growpanel in a 2 by 2 foot growbox should yield more than you consume alone* unless you're a very high level consumer.
Commercial growers on the other hand want to grow as much as they can on their space because rent is expensive, more expensive than electricity.

*Even autoflowers should yield more than enough for a single man.

The key word here being "should".. hahahaha.

I agree... 2x2 with 200 watts of decent light produces a pretty decent yield if you have any idea what you are doing... 2 x2 tent, 4 autos in 2 gallon pots, 200w of light, 10 weeks from sprout yields I don't know 4-8 ounces? Not bad for doing nothing but adding water and a little nutes..

 

[sunny747]

500 ppfd?

So that means I am way over powered with 400w Vero framework in my 3x3?

Timber rates it at 1200 ppfd @ 18"

Electricity rates is very high. Should I dim it?

I don't know because I don't have one of these lights yet.. When you dim, how do you know how much to dim it? Without owning a Par meter.. Do you just take a guess?

I'd say it also makes a difference if you LST, Scrog etc... If you just grow straight up you would want the higher ppfd so your lower nodes get enough energy.

 

[Participant]

You can easily dim it to 800 ppfd and yield will be only a little smaller.
At 600 ppfd yield will be only be 20% smaller or so, give or take.

Wouldn't go below 500.
But you can easily dim it if electricity price is a concern.

i don't want to decrease my yield at all. I don't want to hurt my girls either. Is the PPFD decrease linear if i dim it? I only have 1 plant in there now, and will add 1 every 6 weeks forever.

I don't know because I don't have one of these lights yet.. When you dim, how do you know how much to dim it? Without owning a Par meter.. Do you just take a guess?

I'd say it also makes a difference if you LST, Scrog etc... If you just grow straight up you would want the higher ppfd so your lower nodes get enough energy.

I would have to guess.