Never done led but when I looked Into it years ago I was interested due to lower heat levels. I would say if heat isn't an issue and not knowing your set up run a 1000 w

If I remember correctly two 300w let would give better light penetration and spread due to having two lights and being able to run them closer.

Good luck

There is so much BS LED info dating back to the early days of leds when efficient white leds did not exist, so the carpetbaggers came up with pseudo-science lies that totally discredited the value of white light.

The problem here was anyone who ever grew with HID or HPS knew this was a lie, but somehow, hundreds of thousands of ignorant consumers overlooked the obvious, and drank the Kool-Aid without thinking it through.

These days a quality ~ 250w white based led will easily better a 400w hps and even give a 600 a run for the money

Thanks bubba.

Nuggz, all I see is red/blue LED panels on the market. What do you mean white-based?

The led industry is full of BS.
Plant growing is in fact a science...a quantifiable one at that.
The most directly correlated factor to yield is photon count. It is also the actual way a plant physiologist or and plant scientist talks about, used, and referenced...many times generally thrown under the term PAR.

It is actually very simple to find out the capabilities of any light source(led, hps, chm, lec, plasma, ...)...just ask the manufacture for the PPF. From that figure you have pretty much all you need to know about what the light could possibly do in real life.
If a manufacturer can not supply you with PPF(not ppfd)...they are not worth your time or money...and are just lying out their teeth for your money.
After that you can look into details liek spectrum and optics used to see how well that PPF will be delivered...but without the PPF to start with, there is no way to be a successful grow light.
Simple as that.

PhatNuggz said:

There is so much BS LED info dating back to the early days of leds when efficient white leds did not exist, so the carpetbaggers came up with pseudo-science lies that totally discredited the value of white light.

The problem here was anyone who ever grew with HID or HPS knew this was a lie, but somehow, hundreds of thousands of ignorant consumers overlooked the obvious, and drank the Kool-Aid without thinking it through.

These days a quality ~ 250w white based led will easily better a 400w hps and even give a 600 a run for the money

Click to expand...

So you want just white led?

tags420 said:

The led industry is full of BS.
Plant growing is in fact a science...a quantifiable one at that.
The most directly correlated factor to yield is photon count. It is also the actual way a plant physiologist or and plant scientist talks about, used, and referenced...many times generally thrown under the term PAR.

It is actually very simple to find out the capabilities of any light source(led, hps, chm, lec, plasma, ...)...just ask the manufacture for the PPF. From that figure you have pretty much all you need to know about what the light could possibly do in real life.
If a manufacturer can not supply you with PPF(not ppfd)...they are not worth your time or money...and are just lying out their teeth for your money.
After that you can look into details liek spectrum and optics used to see how well that PPF will be delivered...but without the PPF to start with, there is no way to be a successful grow light.
Simple as that.

Click to expand...

What is ppf?

Midwestjay said:

What is ppf?

Click to expand...

Photosynthetic Photon Flux...how much total light is emitted by the source...in photons.

tags420 said:

Photosynthetic Photon Flux...how much total light is emitted by the source...in photons.

Click to expand...

Thanks

this may give you a headache, or just run screaming from the room to do bong hits to the brain before your head explodes..... what Tags420 said about PPF is spot on, for the money, I believe the white light LED's are the way to go, but I'm just starting the journey with LED's and admit freely I know NOTHING or just enough to be a danger to my garden. Don't even get me started on moles and micromoles..... I get a nosebleed thinking about it lol....

I copied and pasted this from the site I get my fixtures from.

ABOUT PAR, PPF, PPFD…AND (THE RARELY-DISCUSSED) DLI
When LEDs arrived on the market, their tremendous efficiency and money saving potential changed the playing field and lumens, lux and footcandles finally became obsolete metrics for determining light requirements for plants.

Recently, people began referring to PAR, PPF and PPFD as ways to measure light in photosynthetics lighting applications. The purpose of this article is to explain what these terms mean, correct some common misunderstandings and help growers understand how the science behind these terms can be used to determine proper light levels to grow happy, thriving plants.

What the heck is PAR?
Our LED fixtures emit extremely high PAR levels -- far higher than any fixture we know of in our price range and well above it -- a reason we recommend the purchase of a dimmer if you feel you may wish to reduce light levels at some point in the future and why we strongly recommend a dimmer if you require low light levels on a day to day basis. But what exactly is “PAR”?

PAR (Photosynthetically Active Radiation) is a much used (and often misused) term. It is NOT a measurement or “metric” like feet, inches or kilos. Rather, it defines the type of light (scientists call light “electromagnetic radiation”) needed to support photosynthesis in plant life. Through photosynthesis, plants convert light energy into chemical energy, which is the food they use to grow and thrive.

As we all know, some light (like the light from a candle) is visible to the human eye and some (such as infrared) is not. Scientists define different types of light by their “wavelengths” and, for those who are interested, we publish the wavelengths emitted by our LEDs here. These different wavelengths make up the electromagnetic radiation “spectrum”. This spectrum includes X-rays, radio waves and infrared light (none of which are visible to the human eye) and light that we can see such as sunlight, and light from a red or blue LED.

Interestingly, plants use roughly the same part of the spectrum that’s visible to the human eye, but the wavelengths we perceive to be the brightest (i.e. green light) are not the most efficient wavelengths for photosynthesis.

So, the first thing to understand about PAR is that it is the part of the electromagnetic radiation spectrum (light) that is useful to plants and algae to activate photosynthesis -- it is NOT a measurement. What really counts is PPF, PPFD and DLI.

When selecting a lighting system or fixture that will trigger and promote photosynthesis, there are three measurements that are important: how much light the fixture produces, how much of that light is available to the plants and how much light the plant receives during the photoperiod.

Definitions
Photosynthetically Active Radiation (PAR). This is NOT a measurement or “metric” like feet, inches or kilos. PAR defines the type of light which is needed to support photosynthesis in plant life.

Photosynthetic Photon Flux (PPF). A measurement of the total light (photons) emitted by a light source each second. PPF tells us how much PAR is emitted by a light source. Measured in “micromoles per second” and expressed as: μmoles/second

Photosynthetic Photon Flux Density (PPFD). A measurement of the light (photons) that reach the target each second. PPFD is measured over a one meter square area in “micromoles per square meter per second” and expressed as μmol/m2/s.

Day Light Integral (DLI). A cumulative measurement of the total amount of light (photons) that reach the target during the photoperiod. DLI is measured over a one meter square area in “moles per square meter per day” and expressed as mol/m2/d.

Mole. A mole is a term used in science and is equal to something called “Avogadro’s number”, which is 602,214,150,000,000,000,000,000.

Micromole. One millionth of a mole or 602 quadrillion.

Photons. The name physicists give to light particles.

Photoperiod. The period of time during which natural or artificial light is available to promote photosynthesis in plant life each day.

The first measurement is Photosynthetic Photon Flux or “PPF” which measures the total amount of light that is produced by a light source each second. Put another way, PPF tells us how much PAR is emitted by a light source per second. More technically, PPF measures the “photosynthetically active photons emitted by a lighting system per second”. This measurement is expressed in “micromoles per second” and we’ll get to micromoles in a minute. Note though, that PPF does not tell us how much of the measured light actually lands on the plants or any other surface. It is probably the second most important way of measuring a lighting system, but, for whatever reason, 99.9% of lighting companies don’t list it. Build My LED publishes this number for every fixture we build. PPF is expressed by scientists and light engineers as: μmol/second.

The second measurement is PPFD which measures the light that actually arrives at the plant or algae. Photosynthetic Photon Flux Density or “PPFD” is a measurement of the amount of light that actually reaches your plants and algae or, as a scientist might say: “the number of photosynthetically active photons that fall on a given surface each second”. PPFD is a ‘spot’ measurement of a specific location on your plant canopy, and it is measured in micromoles per square meter per second. This measurement is expressed by scientists and light engineers as: μmol/m2/s.

The third measurement is DLI (Day Light Integral) which measures the total amount of light that is delivered to a plant every day. The grower can think of DLI as the plant’s daily “dose” of light though a scientist would probably say DLI is a cumulative measurement of the total number of photons that reach the plants and algae during the daily photoperiod. DLI measures the number of “moles” of photons per square meter per day and is expressed as: mol/m2/d.

Obviously, if you leave your lights on longer, your plants absorb more light. Or, put in more technical language, a lighting system with a lower PPF can deliver the same DLI to an aquarium compared to a lighting system with a higher PPF if the photoperiod is extended. DLI is analogous to the total amount of rain that falls during a storm, as opposed to how fast the rain fell (which would be PPFD). DLI is the most important metric for determining the overall growth rate of plants and algae. Once you know the preferred DLI of your plants and/or algae, you can easily set up a lighting system to deliver the required amount of light. Properly designed photosynthetic lighting systems start with defining the required DLI.

So, what exactly are moles and micromoles?
There are huge numbers of photons or “light particles” in visible light -- in fact, the quantity is so large that we cannot easily express it using normal numbers, so we use two measurements commonly used by scientists when measuring huge quantities. The first number, which is called a Mole, is equal to something called “Avogadro’s number”, which is 602,214,150,000,000,000,000,000! For a more manageable number, a micromole is a millionth of a mole. Much better, right?! In plain English, a micromole of photons (which would be one millionth of Avogadro’s number) is 602 quadrillion. Since these numbers are so large, it is easier to reference quantities of light in moles and micromoles.

In summary:

1. PPF tells us how many photons of light are emitted by a light source each second.
2. PPFD tells us how densely the fixture distributes the light photons on a one meter square target (i.e. your plants and algae) in one second.
3. DLI tells us how many photons were delivered to a one meter square target in a full photoperiod (i.e. a day).

Making it simple
Every aquarium and lighting system is different, and there are numerous factors that affect the total amount of light which is delivered by a light fixture. So, while ‘lumens’ was easy, it really had no consistent link to the amount of light you were delivering to your plants and algae. PAR, PPF, PPFD and DLI are precise and consistent terms and measurements used by scientists, algae researchers, horticulturists and labs around the world -- but they can be difficult to memorize and grasp. So here’s a way to make it easier:

Think of light as rain and the light fixture as a cloud.

PPF tells us how many raindrops are falling from a cloud every second -- that’s easy.

Let’s assume that cloud produces one million raindrops per second. If it is a large cloud the size of the state of Texas, you probably wouldn’t even know it was raining outside. But, if the cloud was the size of a car, you would probably want to put on a life vest if you were directly under this cloud! The raindrop density (PPFD) from the car-sized cloud in the second scenario would be very apparent to the unfortunate person under it. It is the same scenario with lighting systems. PPF tells us how many photons are being produced by a lighting fixture every second, but it doesn’t tell us where the photons are landing. That’s why we need PPF-Density or PPFD.

As an example, a 48” LED light bar, with any of the beam angles we offer, may produce a total of 90 micromoles per second (PPF) -- that’s from the entire fixture. But under it, when you measure the amount of light that arrives at the plant or algae, you are measuring the light that falls on one square meter of surface area every second (PPFD) -- a far more important measurement if you are a plant and one where the number of micromoles is higher in a typical growth environment.

Recently, I had a customer e-mail me about this very fixture. He had seen our published PPF values and said “I heard your fixtures had really high PAR -- but how can that be when the PAR is only 90 directly under the fixture...”

He was confusing the light emitted by the fixture which is 90 PPF (μmoles/second) with the light received by the plants, which is 375 PPFD (μmoles/m2/s). In this case, the 375 PPFD was measured six inches under the fixture.

As we have seen, the 375 PPFD is the important measurement of PAR -- the Photosynthetically Active Radiation that matters to the plants. Ideally, you want to take spot measurements across your plant growth area and then average these numbers to get the most meaningful PPFD metric for your plants. In most applications, we are interested in the average amount of light being delivered to the plants...not just the Max PPFD reading.

I hope this article has been useful -- our goal is to help growers understand LED technology and the benefits of using this economical, environmentally sound and powerful light source to grow healthy plants.

It doesnt have me running I'm really wanting to get some LED panels in the near future. You have had success with flowering with LED panels?

I do alright.... still dialing it in, bear in mind I'm just growing for my own personal, and I don't need much, a zip lasts me a LONG time lol... I do a couple hits in the morning to work the kinks out, and a few more at night to help me sleep. If I'm hurting ( and I'm getting at an age where stuff hurts alla damn time ) I smoke a little more. Let's just say I'm keeping up with my own supply and demand lol. My garden is down for the summer, already starting to warm up here and I can't afford lights and a/c, or I'd snag some pics for ya.

This what Cree CXB 3590 can do I've been using cobs from Cree for 16 months now no HID lighting at all lol I forgot to mention I made them myself and so can you.





pics taken today and harvesting tomorrow .

Midwestjay said:

So you want just white led?

Click to expand...

I have been asking this question ever since I started buying them a few years ago.

What I infer from delivered knowledge:
I believe they are 'reflective' lights.
A high power, high frequency, LED is placed such that emitted light strikes a reflective surface that is designed to re-emit white light.

The nature of the reflective surface determines the color spectrum the plant sees.

These things are cheep and cool.

No fans = that long life is not limited by how long the fan works.

Corrections and clarifications are invited, neigh begged for.

COBs (chips on board, a bunch of LEDs in a single package) being used by Realstyles are manufactured by coating blue LEDs with phosphor to make various shades of white. The 3000K, 3500K (and maybe 4000K) contain enough red output for good budding.

I've had good crops using red and blue diodes but COBs are more efficient.
I'm building my own stuff but tastyled.com makes a lot of sense for a pre-built luminaire.

seaslug said:

COBs (chips on board, a bunch of LEDs in a single package) being used by Realstyles are manufactured by coating blue LEDs with phosphor to make various shades of white. The 3000K, 3500K (and maybe 4000K) contain enough red output for good budding.

I've had good crops using red and blue diodes but COBs are more efficient.
I'm building my own stuff but tastyled.com makes a lot of sense for a pre-built luminaire.

Click to expand...

Don't forget about Johnson Grow lights and Pacific light Concepts they use top bin Cree cobs

Keep in mind REALSTYLES and tags420 have forgotten more about LED's than I'm probably ever going to know.....they, and a few others on here, inspired my move to LED....I'm just not real handy with tech stuff and being able to build my own.

The good cob full spectrum lights have infra red and uv emitting diodes.

3500k white cobs,have a good full spectrum of colours.you don't need anything else.watch realstyles you tube vids.or green genes.

REALSTYLES said:

This what Cree CXB 3590 can do I've been using cobs from Cree for 16 months now no HID lighting at all lol I forgot to mention I made them myself and so can you. .

Click to expand...

I have been using leds for over a year now and my problem is the amount of heat at the top of the plant I have a height problem but they don't run as cool as most think. They also are a directional light and have a narrow lateral coverage problem. I am building a new greenhouse and going to put in some side lighting built to fit. Is not any cheeper but is light where you want it. I found that T5and T8 fixtures mounted on the wall makes a big difference.
I think and am not sure but is white light and is where they shade themselves gets more light and you only have to add a few mine came when woman back into a light I dismantled and put on wall threw rest in scrap been, she felt so bad bought me a full sped of the 8 bulbs. It makes a big difference not in large ways but the lower inside nugs get fuller and that's what I had problems with the leds. You don't loose as many leaves on lower part of the plant