MasterShake1
Member
If a light says that it puts out 2155 and you add another one do you add those and then would that be to much lumens or can you use two of 2700 or do you have to get two that equal the 2700 I am confused please help
Lumens, Lux, and Adding It all Up
- Thread starter ceestyle
- Start date
shiva71
Well-Known Member
Wow...
Well,i spent all day yeasterday reading the CFL advantages v disadvantages sticky (if you dig splitting migranes i strongly recommend Lastfrontiers posts) and guess what...im still miffed.
Ive juggled the stats every which way you can and i can only come to one conclusion: HID kicks CFLs ass.
Fewer watts with more lumens surely beats more watts with fewer lumens? Eg, if i put a 250w limit on my light wattage cos i dont want a huge leccy bill, 250w puts out 30,000. Within this wattage, 6 x 42w CFL = 252w giving 16,200. In my 2 x 3 ft closet, 250w HID = 5000l per sq/ft, happy girls, 252w cfl = 2700l per sq/ft, below the absolute minimum recommended by most growers....
From what ive read, cfls are only worthwhile if a) youre in a position to reach a good lumen output regardless of the fact that you'll need almost double the watts to do so or b) in a cutting/clone room where light doesnt need to be so strong.
L8rs guys
Well,i spent all day yeasterday reading the CFL advantages v disadvantages sticky (if you dig splitting migranes i strongly recommend Lastfrontiers posts) and guess what...im still miffed.
Ive juggled the stats every which way you can and i can only come to one conclusion: HID kicks CFLs ass.
Fewer watts with more lumens surely beats more watts with fewer lumens? Eg, if i put a 250w limit on my light wattage cos i dont want a huge leccy bill, 250w puts out 30,000. Within this wattage, 6 x 42w CFL = 252w giving 16,200. In my 2 x 3 ft closet, 250w HID = 5000l per sq/ft, happy girls, 252w cfl = 2700l per sq/ft, below the absolute minimum recommended by most growers....
From what ive read, cfls are only worthwhile if a) youre in a position to reach a good lumen output regardless of the fact that you'll need almost double the watts to do so or b) in a cutting/clone room where light doesnt need to be so strong.
L8rs guys
DannyGreenEyes
Well-Known Member
Hi everyone, I'm about to start my first grow and I'm a little lost right now because my plans just went through a major change. I was going to use CFLs but I'm hearing way too many reports of light & fluffy buds. It could be just bad placement of or the wrong ammount of bulbs being used, but I can't afford to take the chance on this grow.
I'll be growing in a walk in closet and I don't really have to worry too much about the smell. I'll have 2 fans at the closet door for ventilation, 1 low pointed out & 1 hi pointed in. I'll be growing 2 Sour Diesel, 2 Citrus Diesel, & 2 Grape Ape plants, and I'll be using a topping technique that will produce up to 4 colas per plant. I'll be setting up in the middle of the empty closet and the set up I'm thinking of are two rows of plants with a light above them and 1 more light on either side (for side growth) for a total of 3 lights.
I just have a few questions and you guys really sound like you know lights.
Will 3 lights produce too much heat in a walk in closet? (approx 84" x 56", approx 8' ceiling).
If 3 isn't too many, would you please recomend a good light to use that will give a good grow without being overkill?
If 3 is too many, would 2 work better hung above the plants, slightly out to the side, and angled at a 45degree angle in toward the plants (adding foil covered cardboard to help light exposure to the side of the plants)?
If 2 is a better set up for 6 plants, can you suggest a good light that will give a good grow without being overkill for a 2 light set up?
I appreciate any help you can give me.
P.S. Money is an issue right now, so I can't afford any whistles or bells. I'm just looking for a good yield and good quality.
I'll be growing in a walk in closet and I don't really have to worry too much about the smell. I'll have 2 fans at the closet door for ventilation, 1 low pointed out & 1 hi pointed in. I'll be growing 2 Sour Diesel, 2 Citrus Diesel, & 2 Grape Ape plants, and I'll be using a topping technique that will produce up to 4 colas per plant. I'll be setting up in the middle of the empty closet and the set up I'm thinking of are two rows of plants with a light above them and 1 more light on either side (for side growth) for a total of 3 lights.
I just have a few questions and you guys really sound like you know lights.
Will 3 lights produce too much heat in a walk in closet? (approx 84" x 56", approx 8' ceiling).
If 3 isn't too many, would you please recomend a good light to use that will give a good grow without being overkill?
If 3 is too many, would 2 work better hung above the plants, slightly out to the side, and angled at a 45degree angle in toward the plants (adding foil covered cardboard to help light exposure to the side of the plants)?
If 2 is a better set up for 6 plants, can you suggest a good light that will give a good grow without being overkill for a 2 light set up?
I appreciate any help you can give me.
P.S. Money is an issue right now, so I can't afford any whistles or bells. I'm just looking for a good yield and good quality.
Green Giant84
Active Member
If u no any 1 that's lookin 4 a great grow box I have a Bloombox 4 sale. Only 10 months old and works perfect and still looks brand new only askin $2500. Comes with tubs and Connoisseur A and B Nutrients!!!!!!!!
bobkessel
Active Member
"PAR" Photosynthentic Active Radiation for plant growing is a measurment of this energy being delivered/ Actual light intensity in the 400-700nm wavelenght band. The number from 2000 the sun to 0 no light energy at all is expressed as or in microEnsteins per second per square meter being delivered from your light source. This way tells us easily just how much of this energy the plant needs is in the lights we are using. For growing I believe this type of meter is the very best tool for measureing light. They will tell you exactly where your plants will thrive and or just survive from a lighting perspective of coarse.
Everything you are showing is a good estimator for lights that shine in 360 degress. It your using LED lights your dealing with a directional light and LEDs work more light painting with light vs. filling the room full of it as HPS and CFL do. This is where a PAR meter can be a great tool. Understanding the complete story is to also understand how your light source is going to deliver the energy it has to give. I believe this is where most of the stories about LED not being able to penatrate the plants come from. Light does not work that way. It goes where ever it wants to but the further away from its source the less dense it becomes. Good reason to have a PAR meter to be sure and check you are getting that energy to all the spots you need it. You can start to make your operations much more efficient once you understand this. The way we grow now we waste much of this energy all over the room vs getting it to the plants. This is why I know that LED in time will over take all growing. Economics always has its say in things.
Bob
Everything you are showing is a good estimator for lights that shine in 360 degress. It your using LED lights your dealing with a directional light and LEDs work more light painting with light vs. filling the room full of it as HPS and CFL do. This is where a PAR meter can be a great tool. Understanding the complete story is to also understand how your light source is going to deliver the energy it has to give. I believe this is where most of the stories about LED not being able to penatrate the plants come from. Light does not work that way. It goes where ever it wants to but the further away from its source the less dense it becomes. Good reason to have a PAR meter to be sure and check you are getting that energy to all the spots you need it. You can start to make your operations much more efficient once you understand this. The way we grow now we waste much of this energy all over the room vs getting it to the plants. This is why I know that LED in time will over take all growing. Economics always has its say in things.
Bob
Shrubs First
Well-Known Member
The problem with everything is that it is all in photometry terms, It needs to be completely converted to radiometry, Irradiance is a more sensable way to measure the energy absorbed by plants, Lumens are useless, Candela useless, even PAR doesnt make much sense, the Kelvin scale as well, it's all for the Human eye....
In photometric quantities every wavelength is weighted according to how sensitive the human eye is to it, while radiometric quantities use unweighted absolute power. For example, the eye responds much more strongly to green light than to red, so a green source will have greater luminous flux than a red source with the same radiant flux would. Radiant energy outside the visible spectrum does not contribute to photometric quantities at all, so for example a 1000 watt space heater may put out a great deal of radiant flux (1000 watts, in fact), but as a light source it puts out very few lumens (because most of the energy is in the infrared, leaving only a dim red glow in the visible)
Watts vs Lumens
Watts are units of radiant flux while lumens are units of luminous flux. A comparison of the watt and the lumen illustrates the distinction between radiometric and photometric units.
The watt is a unit of power. We are accustomed to thinking of light bulbs in terms of power in watts. This power is not a measure of the amount of light output, but rather indicates how much energy the bulb will use. Because incandescent bulbs sold for "general service" all have fairly similar characteristics (same spectral power distribution), power consumption provides a rough guide to the light output of incandescent bulbs.
Watts can also be a direct measure of output. In a radiometric sense, an incandescent light bulb is about 80% efficient: 20% of the energy is lost (e.g. by conduction through the lamp base). The remainder is emitted as radiation, mostly in the infrared. Thus, a 60 watt light bulb emits a total radiant flux of about 45 watts. Incandescent bulbs are, in fact, sometimes used as heat sources (as in a chick incubator), but usually they are used for the purpose of providing light. As such, they are very inefficient, because most of the radiant energy they emit is invisible infrared. A compact fluorescent lamp can provide light comparable to a 60 watt incandescent while consuming as little as 15 watts of electricity.
The lumen is the photometric unit of light output. Although most consumers still think of light in terms of power consumed by the bulb, in the U.S. it has been a trade requirement for several decades that light bulb packaging give the output in lumens. The package of a 60 watt incandescent bulb indicates that it provides about 900 lumens, as does the package of the 15 watt compact fluorescent.
The lumen is defined as amount of light given into one steradian by a point source of one candela strength; while the candela, a base SI unit, is defined as the luminous intensity of a source of monochromatic radiation, of frequency 540 terahertz, and a radiant intensity of 1/683 watts per steradian. (540 THz corresponds to about 555 nanometres, the wavelength, in the green, to which the human eye is most sensitive. The number 1/683 was chosen to make the candela about equal to the standard candle, the unit which it superseded).
Combining these definitions, we see that 1/683 watt of 555 nanometre green light provides one lumen.
The relation between watts and lumens is not just a simple scaling factor. We know this already, because the 60 watt incandescent bulb and the 15 watt compact fluorescent can both provide 900 lumens.
The definition tells us that 1 watt of pure green 555 nm light is "worth" 683 lumens. It does not say anything about other wavelengths. Because lumens are photometric units, their relationship to watts depends on the wavelength according to how visible the wavelength is. Infrared and ultraviolet radiation, for example, are invisible and do not count. One watt of infrared radiation (which is where most of the radiation from an incandescent bulb falls) is worth zero lumens. Within the visible spectrum, wavelengths of light are weighted according to a function called the "photopic spectral luminous efficiency." According to this function, 700 nm red light is only about 4% as efficient as 555 nm green light. Thus, one watt of 700 nm red light is "worth" only 27 lumens.
Because of the summation over the visual portion of the EM spectrum that is part of this weighting, the unit of "lumen" is color-blind: there is no way to tell what color a lumen will appear. This is equivalent to evaluating groceries by number of bags: there is no information about the specific content, just a number that refers to the total weighted quantity.
Basically, any bulb company who brags that their "HID bulb" which was specifically formulated for plants is putting out more Lumens than the next bulb company, and shows some bs CRI chart which is only showing colors the human eye recognizes as colors is BS! There needs to be a new standard.
From this you can reason that a light which is formulated specifically for plant growth, would probably be putting out less lumens then most Lumen directed bulbs, and still be making a better impact on plant growth and response.
We relate the plants' CRI chart to the wavelengths that can be seen by the human eye, it is all done by color, yet even THAT is biased to the human eye.
A plants' CRI doesnt depend on color.
People say blue light for veg, red light for flower, thats BS plants don't see colors...
You say you could use a 400w Metal halide for veg, and 1000 watt for flowering because plants need more lumens in the flowering period..
Well in the later months in nature the sun is actually lower in the sky making it seem not as bright, and that means the plants wouldnt be getting MORE light in the flowering period in nature, the would be getting LESS. Also because the sun is lower in the sky, different gases in the atmosphere are reflected making it seem like it is more red spectrum coming from the sun. This is also BS because no matter what that is, as long as the plants are getting sunlight they are receiving a FULL spectrum light, not a majority of one over the other.
Any takers?
In photometric quantities every wavelength is weighted according to how sensitive the human eye is to it, while radiometric quantities use unweighted absolute power. For example, the eye responds much more strongly to green light than to red, so a green source will have greater luminous flux than a red source with the same radiant flux would. Radiant energy outside the visible spectrum does not contribute to photometric quantities at all, so for example a 1000 watt space heater may put out a great deal of radiant flux (1000 watts, in fact), but as a light source it puts out very few lumens (because most of the energy is in the infrared, leaving only a dim red glow in the visible)
Watts vs Lumens
Watts are units of radiant flux while lumens are units of luminous flux. A comparison of the watt and the lumen illustrates the distinction between radiometric and photometric units.
The watt is a unit of power. We are accustomed to thinking of light bulbs in terms of power in watts. This power is not a measure of the amount of light output, but rather indicates how much energy the bulb will use. Because incandescent bulbs sold for "general service" all have fairly similar characteristics (same spectral power distribution), power consumption provides a rough guide to the light output of incandescent bulbs.
Watts can also be a direct measure of output. In a radiometric sense, an incandescent light bulb is about 80% efficient: 20% of the energy is lost (e.g. by conduction through the lamp base). The remainder is emitted as radiation, mostly in the infrared. Thus, a 60 watt light bulb emits a total radiant flux of about 45 watts. Incandescent bulbs are, in fact, sometimes used as heat sources (as in a chick incubator), but usually they are used for the purpose of providing light. As such, they are very inefficient, because most of the radiant energy they emit is invisible infrared. A compact fluorescent lamp can provide light comparable to a 60 watt incandescent while consuming as little as 15 watts of electricity.
The lumen is the photometric unit of light output. Although most consumers still think of light in terms of power consumed by the bulb, in the U.S. it has been a trade requirement for several decades that light bulb packaging give the output in lumens. The package of a 60 watt incandescent bulb indicates that it provides about 900 lumens, as does the package of the 15 watt compact fluorescent.
The lumen is defined as amount of light given into one steradian by a point source of one candela strength; while the candela, a base SI unit, is defined as the luminous intensity of a source of monochromatic radiation, of frequency 540 terahertz, and a radiant intensity of 1/683 watts per steradian. (540 THz corresponds to about 555 nanometres, the wavelength, in the green, to which the human eye is most sensitive. The number 1/683 was chosen to make the candela about equal to the standard candle, the unit which it superseded).
Combining these definitions, we see that 1/683 watt of 555 nanometre green light provides one lumen.
The relation between watts and lumens is not just a simple scaling factor. We know this already, because the 60 watt incandescent bulb and the 15 watt compact fluorescent can both provide 900 lumens.
The definition tells us that 1 watt of pure green 555 nm light is "worth" 683 lumens. It does not say anything about other wavelengths. Because lumens are photometric units, their relationship to watts depends on the wavelength according to how visible the wavelength is. Infrared and ultraviolet radiation, for example, are invisible and do not count. One watt of infrared radiation (which is where most of the radiation from an incandescent bulb falls) is worth zero lumens. Within the visible spectrum, wavelengths of light are weighted according to a function called the "photopic spectral luminous efficiency." According to this function, 700 nm red light is only about 4% as efficient as 555 nm green light. Thus, one watt of 700 nm red light is "worth" only 27 lumens.
Because of the summation over the visual portion of the EM spectrum that is part of this weighting, the unit of "lumen" is color-blind: there is no way to tell what color a lumen will appear. This is equivalent to evaluating groceries by number of bags: there is no information about the specific content, just a number that refers to the total weighted quantity.
Basically, any bulb company who brags that their "HID bulb" which was specifically formulated for plants is putting out more Lumens than the next bulb company, and shows some bs CRI chart which is only showing colors the human eye recognizes as colors is BS! There needs to be a new standard.
From this you can reason that a light which is formulated specifically for plant growth, would probably be putting out less lumens then most Lumen directed bulbs, and still be making a better impact on plant growth and response.
We relate the plants' CRI chart to the wavelengths that can be seen by the human eye, it is all done by color, yet even THAT is biased to the human eye.
A plants' CRI doesnt depend on color.
People say blue light for veg, red light for flower, thats BS plants don't see colors...
You say you could use a 400w Metal halide for veg, and 1000 watt for flowering because plants need more lumens in the flowering period..
Well in the later months in nature the sun is actually lower in the sky making it seem not as bright, and that means the plants wouldnt be getting MORE light in the flowering period in nature, the would be getting LESS. Also because the sun is lower in the sky, different gases in the atmosphere are reflected making it seem like it is more red spectrum coming from the sun. This is also BS because no matter what that is, as long as the plants are getting sunlight they are receiving a FULL spectrum light, not a majority of one over the other.
Any takers?
Shrubs First
Well-Known Member
PAR Light & Nanometers in Horticulture
PAR light and Nanometers are commonly misunderstood in relation to horticulture. The basic concept with
PAR light is that plants only really need the peaks of photosynthesis, or just the range of visible light that
spans 400 and 700nm range (approx.)
Nanometers are a measurement that scientists made up to explain what they were seeing. The word
nanometer literally refers to one billionth of a meter. Before that it was an Angstrom, and a millimicron, etc.
In science, references for references are often found to be flawed.
Both of these terms (PAR and Nanometers) are man-made, and therefore subject to the knowledge and
interpretation of those who made it. Plants just want what the Sun has provided them for millions of years,
what they need for their life processes. Humans can’t selectively break the light that shines on the Earth into
just what falls into a visible range. There are portions of Sunlight that we don’t see with our eyes, but that
plants use in their own way.
The plant efficiency curve (seen below) was historically used in horticulture, but is really for humans more
than it ever was for plants. People can’t cherry-pick the light from the Sun and nature doesn’t have two brick
walls that say 400 and 700 nanometers.
The plant sensitivity curve
represents the traditional basis for
PAR light. The idea is that peaks of
red and blues are enough for proper
plant development.
Plants want the Sun. Plants use all
the light that they get from the Sun
to make chlorophyll a and b, and
provide the electron volts to the light
harvesting complexes in the leaf; aka
Photosystem 1 and Photosystem 2.
Light is a complex subject; light, light delivery, spectrum, frequency, and then the photobiology, plant
science, quantum physics and more. The complexities of these disciplines only permit short explanation
in a single white paper. Plants want the Sun, but the Sun is twice the energy they need for maximum
photosynthesis. Too much light, too much heat, and too much humidity all inhibit the photosynthetic
process – aka photo-inhibition.
Light has properties of wavelengths,
and long wavelengths – wave physics
and particle physics are a part of that.
Each color of light travels at its own
speed, each carrying a certain number
of electron volts; there’s more than
one speed of light. Plants want all the
colors all the time.
The relationship between frequency
and wavelength are inversely related.
The Sun is shining with full spectrum
light, at a specific frequency. Higher
frequency electronics produce light
that’s closer to the Sun, but that man
can’t perfectly replicate. The Sun shines
in space in the Penta and Terra Hertz,
but not all that is received on the Earth
PAR light is an expression for the visible spectrum, but is no reference for what plants want. Plants just
care about the incident energy, the electron volts, that can actually be delivered to the leaf, that the plant
can actually assimilate for photosynthesis. Photosynthesis, for example, will stop on the leaf surface when
Sunlight levels reach approx. 6500 FC. More light isn’t always better. The Sun puts out approx. 10,000 FC;
twice what they require for maximum photosynthesis. Plants have just adapted to those excess levels of
natural Sunlight, to become the plants we see in Nature now.
PAR light and Nanometers are commonly misunderstood in relation to horticulture. The basic concept with
PAR light is that plants only really need the peaks of photosynthesis, or just the range of visible light that
spans 400 and 700nm range (approx.)
Nanometers are a measurement that scientists made up to explain what they were seeing. The word
nanometer literally refers to one billionth of a meter. Before that it was an Angstrom, and a millimicron, etc.
In science, references for references are often found to be flawed.
Both of these terms (PAR and Nanometers) are man-made, and therefore subject to the knowledge and
interpretation of those who made it. Plants just want what the Sun has provided them for millions of years,
what they need for their life processes. Humans can’t selectively break the light that shines on the Earth into
just what falls into a visible range. There are portions of Sunlight that we don’t see with our eyes, but that
plants use in their own way.
The plant efficiency curve (seen below) was historically used in horticulture, but is really for humans more
than it ever was for plants. People can’t cherry-pick the light from the Sun and nature doesn’t have two brick
walls that say 400 and 700 nanometers.
The plant sensitivity curve
represents the traditional basis for
PAR light. The idea is that peaks of
red and blues are enough for proper
plant development.
Plants want the Sun. Plants use all
the light that they get from the Sun
to make chlorophyll a and b, and
provide the electron volts to the light
harvesting complexes in the leaf; aka
Photosystem 1 and Photosystem 2.
Light is a complex subject; light, light delivery, spectrum, frequency, and then the photobiology, plant
science, quantum physics and more. The complexities of these disciplines only permit short explanation
in a single white paper. Plants want the Sun, but the Sun is twice the energy they need for maximum
photosynthesis. Too much light, too much heat, and too much humidity all inhibit the photosynthetic
process – aka photo-inhibition.
Light has properties of wavelengths,
and long wavelengths – wave physics
and particle physics are a part of that.
Each color of light travels at its own
speed, each carrying a certain number
of electron volts; there’s more than
one speed of light. Plants want all the
colors all the time.
The relationship between frequency
and wavelength are inversely related.
The Sun is shining with full spectrum
light, at a specific frequency. Higher
frequency electronics produce light
that’s closer to the Sun, but that man
can’t perfectly replicate. The Sun shines
in space in the Penta and Terra Hertz,
but not all that is received on the Earth
PAR light is an expression for the visible spectrum, but is no reference for what plants want. Plants just
care about the incident energy, the electron volts, that can actually be delivered to the leaf, that the plant
can actually assimilate for photosynthesis. Photosynthesis, for example, will stop on the leaf surface when
Sunlight levels reach approx. 6500 FC. More light isn’t always better. The Sun puts out approx. 10,000 FC;
twice what they require for maximum photosynthesis. Plants have just adapted to those excess levels of
natural Sunlight, to become the plants we see in Nature now.
Were you hi when you wrote this?
weedyweedy
Active Member
Could be copy and paste and he just took out the jpegs.
This is a nice thread.
This is a nice thread.
Why would you copypaste such nonsensical bullshit? There is just so much wrong up there I don't know where to begin....
About a hundred years ago scientists had less sophisticated equipment and therefore could not measure in nanometers. It was at that time that they used millimicrons. Later, the equipment became more advanced and they could measure in thousands of nanometers (angstroms). Today, nanometers are used to measure distance just like meters and kilometers are - just on a very small scale. Scientists didn't make it up to explain light they literally measured the distance between two peaks of the light wave. The wavelength is used to describe the energy of the light and therefore the color; blue light having more energy than red due to the closer wavelength (lower distance).
PAR is a weighting system similar to the luminosity function, so that a light source can be evaluated based on how well it stimulates oxygen evolution (i.e. performs photosynthesis) instead of how bright it looks to a human eye. The only shortfall of PAR is that it does not speak to balance. All plants require both red and blue light and some plants even require a minimal amount of wavelengths in between (or beyond).
The basis for PAR is derived from experiments where a leaf was exposed to light of specific wavelengths. The incident light on the surface of the leaf was measured (for a total) and then the light that shone through the bottom of the leaf was measured and also the light that reflected from the leaf was measured. The sum of reflectance and transmission subtracted from the incident light gives the absorption. Other experiments enclosed chloroplasts then measured the amount of oxygen produced from a minimal instesity of specific wavelengths. In those experiments, infrared light (>700 nm) was found to not produce oxygen while ultraviolet light (<300 nm) was found to damage DNA and subsequently destroy the cells.
Anyway, just because light (especially in realtion to horticulture) can be complex doesn't mean you should go off all half-cocked about it. Don't be the cause of misinformation.
About a hundred years ago scientists had less sophisticated equipment and therefore could not measure in nanometers. It was at that time that they used millimicrons. Later, the equipment became more advanced and they could measure in thousands of nanometers (angstroms). Today, nanometers are used to measure distance just like meters and kilometers are - just on a very small scale. Scientists didn't make it up to explain light they literally measured the distance between two peaks of the light wave. The wavelength is used to describe the energy of the light and therefore the color; blue light having more energy than red due to the closer wavelength (lower distance).
PAR is a weighting system similar to the luminosity function, so that a light source can be evaluated based on how well it stimulates oxygen evolution (i.e. performs photosynthesis) instead of how bright it looks to a human eye. The only shortfall of PAR is that it does not speak to balance. All plants require both red and blue light and some plants even require a minimal amount of wavelengths in between (or beyond).
The basis for PAR is derived from experiments where a leaf was exposed to light of specific wavelengths. The incident light on the surface of the leaf was measured (for a total) and then the light that shone through the bottom of the leaf was measured and also the light that reflected from the leaf was measured. The sum of reflectance and transmission subtracted from the incident light gives the absorption. Other experiments enclosed chloroplasts then measured the amount of oxygen produced from a minimal instesity of specific wavelengths. In those experiments, infrared light (>700 nm) was found to not produce oxygen while ultraviolet light (<300 nm) was found to damage DNA and subsequently destroy the cells.
Anyway, just because light (especially in realtion to horticulture) can be complex doesn't mean you should go off all half-cocked about it. Don't be the cause of misinformation.
bifter
Well-Known Member
Right guys that has all gone waaaaaayy over my head in easy terms would two of these give twice as many lumens but cost just over half the electricity of a 400 w hps
http://cgi.ebay.co.uk/2-x-105w-Blue-6500k-Red-2700k-CFL-grow-lamp-bulb-ES-E27_W0QQitemZ190373429327QQcmdZViewItemQQptZUK_HomeGarden_Garden_PlantsSeedsBulbs_JN?hash=item2c5324004f
http://cgi.ebay.co.uk/2-x-105w-Blue-6500k-Red-2700k-CFL-grow-lamp-bulb-ES-E27_W0QQitemZ190373429327QQcmdZViewItemQQptZUK_HomeGarden_Garden_PlantsSeedsBulbs_JN?hash=item2c5324004f
bubblegoogles
Member
I believe your numbers for total lux of the lights are not correct they should be 6500 not 65000 and 13000 not 130000. An average office or classroom has 600 lux. If it were 65000 and 130000 it would be like you were in the sun!! Ever use a quantum meter it reads only par lighting in units of uMol/ second it is the cheapest way of measuring usable plant light.
jesus420
Well-Known Member
AHEM.
The real problem is talking about LUX and LUMENS in the first place, which have almost nothing to do with photosynthesis.
Seriously, PAR (photosynthetically active radiation) is what we should be talking about now, it measures light usable to plants. LUX is based on green and yellow wavelengths only, because these are what make lights bright or dim to the human eye, or eyes do not perceive red as well, and blue will always seem dim.
Red and blue happen to be the most active light spectrums for photosynthesis, however.
If you're not measuring par, you're wasting your time and money.
The real problem is talking about LUX and LUMENS in the first place, which have almost nothing to do with photosynthesis.
Seriously, PAR (photosynthetically active radiation) is what we should be talking about now, it measures light usable to plants. LUX is based on green and yellow wavelengths only, because these are what make lights bright or dim to the human eye, or eyes do not perceive red as well, and blue will always seem dim.
Red and blue happen to be the most active light spectrums for photosynthesis, however.
If you're not measuring par, you're wasting your time and money.
sir rance alot
Active Member
yeah........but can I grow a plant using mah flashlight?
Hi all,
Does anyone know how far from the plant a 150W HID will compare to a 25W CFL 1 inch away from a plant? I assume it might be a lot but just to know...
Lets say you have lot of CFLs in a small area, like if you surround one plant with lots of it, can you get the same performance as an HID for the same plant? Or still wave length will come in case and its not possible to achieve that?
Does anyone know how far from the plant a 150W HID will compare to a 25W CFL 1 inch away from a plant? I assume it might be a lot but just to know...
Lets say you have lot of CFLs in a small area, like if you surround one plant with lots of it, can you get the same performance as an HID for the same plant? Or still wave length will come in case and its not possible to achieve that?
Mr.Natural
Active Member
if close enough being careful not to burn plant ...very close HID penetrates some what better... but much more heatHi all,
Does anyone know how far from the plant a 150W HID will compare to a 25W CFL 1 inch away from a plant? I assume it might be a lot but just to know...
10 to 12 inches if vented properly...
Lets say you have lot of CFLs in a small area, like if you surround one plant with lots of it, can you get the same performance as an HID for the same plant? Or still wave length will come in case and its not possible to achieve that?
