Are you sure you are using the right bulb?

[Etnavyguy]

For that matter, i'm not sure I am using the correct bulbs. I was just reading the forums and saw someone contradict what I had read earlier so I would like to set the record straight, and I will need some input.

1. According to greenmanspage.com/guides/lightguide.html and weedfarmer.com/cannabis/lightguide_guide.php

400-520 nm (promotes vegetative growth)

610-720 nm (promotes flowering and budding)

Found this online
Wavelength (nanometers) = 3,000,000 / Col temp (Kelvin)

400-520 is now 7500-5770 kelvin

610-720 is now 4918-4166 kelvin

This was said in the forums recently

Yeah, you can choose 3000k for vegging and switch to 6500 for flowering

Can anyone Confirm/Deny?

 

[BBFan]

Anonymous had it backwards.

Cool / Blue approx. 6500k is for veg
Metal Halides operate in this range

Warm / Red approx 3000k is for flower
HPS operate in this range

Hope this helps.

 

[HippyInEngland]

Kelvin is a measurement of temperature.

[K] = ([°F] + 459.67) × 5⁄9

[K] = [°C] + 273.15

eace:

 

[Etnavyguy]

Wavelength (nanometers) = 3,000,000 / Col temp (Kelvin)

I agree he had it backward but 3000 K?

3000 K = 1000 nm

If you check out the charts I linked in the first post, you can clearly see that anything in the 3000k mark would be ineffective. My entire argument hinges on the two graphs that i linked being accurate and applicable to MJ. Please review my findings.

Also I'm not sure if HippyInEngland is joking or not. If you are it is very funny in the sense that someone posting in a forums such as this would say something so ridiculous. If you are not joking, then i'm sorry and I hope life works out for you.

 

[PencilHead]

Wavelength (nanometers) = 3,000,000 / Col temp (Kelvin)

I agree he had it backward but 3000 K?

3000 K = 1000 nm

If you check out the charts I linked in the first post, you can clearly see that anything in the 3000k mark would be ineffective. My entire argument hinges on the two graphs that i linked being accurate and applicable to MJ. Please review my findings.

Also I'm not sure if HippyInEngland is joking or not. If you are it is very funny in the sense that someone posting in a forums such as this would say something so ridiculous. If you are not joking, then i'm sorry and I hope life works out for you.

:confused2: I'm certainly lacking enough brain cells to join in this declining discussion. Good luck with that, Naval guy.

 

[HippyInEngland]

Also I'm not sure if HippyInEngland is joking or not. If you are it is very funny in the sense that someone posting in a forums such as this would say something so ridiculous. If you are not joking, then i'm sorry and I hope life works out for you.

Kelvin’s measure the colour temperature of a full spectrum light source.

However there IS a relationship between a colour temperature and the peak wavelength in its spectrum.

It's called Wien's law.

Wavelength (nanometers) = 3,000,000 / Col temp (Kelvin).

So at 4,500K, the peak wavelength is 666nm (red) at 6,000K the peak wavelength is 500nm (bluish green) and at 7,500K the peak wavelength is 400nm (deep blue)

Outside these temperatures, the peak is outside the visible spectrum.

And in every case, that's just the peak wavelength - all other wavelengths are present as well, in slightly lesser intensities, adding up to a more-or-less white result.

eace:

 

[astrobud]

so in retrospective, 6000k range for veg and2000k for flowering i get it

 

[dirtyolsouth]

Very interesting and informative yet deep discussion.... thanks guys! All I know is the "Red" ones are for flowering and the "Blue" ones are for vegging... Thank god for color coding!

Peace!

 

[Etnavyguy]

Kelvin is a measurement of temperature.

[K] = ([°F] + 459.67) × 5⁄9

[K] = [°C] + 273.15

eace:

I am not disputing the correctness of these equations, simply why you put them in the forum.

My point is according to the information provided a bulb which has a light emission curve that peaks at 3000k, would be far from ideal since that corresponds to wavelengths that are not absorbed.

 

[HippyInEngland]

I am not disputing the correctness of these equations, simply why you put them in the forum.

My point is according to the information provided a bulb which has a light emission curve that peaks at 3000k, would be far from ideal since that corresponds to wavelengths that are not absorbed.

When you have been here a bit longer you will realise that the forum does not work in 'black and white', it is full of people with diverse knowledge and in depth abilities to point you into ways of understanding the background behind your questions so you yourself can go research the basis of your confusion.

The equations I posted were so you have the foundation to work out the plants 'Ideals' yourself.

Sometimes its a good thing to have your brain do more than just tell it to type with a keyboard.

This is the wrong attitude to have on this forum.

Also I'm not sure if HippyInEngland is joking or not. If you are it is very funny in the sense that someone posting in a forums such as this would say something so ridiculous. If you are not joking, then i'm sorry and I hope life works out for you.

eace:

 

[MindzEye]

I know for a long time Ed Rosenthal would write in Canibis Culture that he didnt notice much of a yield increase by switching bulbs. He said its fine to veg under a hps lamp

However Jorge Cervantes in the past wrote numerous times in High Times that you should use blue (6500k range) for grow and red (2000k range) for bloom

I switch my bulbs because I can get them dirt cheap, I have thought many times about Ed Rosenthals theory... I guess theres only one way to find out...

 

[dirtyolsouth]

I know for a long time Ed Rosenthal would write in Canibis Culture that he didnt notice much of a yield increase by switching bulbs. He said its fine to veg under a hps lamp

However Jorge Cervantes in the past wrote numerous times in High Times that you should use blue (6500k range) for grow and red (2000k range) for bloom

I switch my bulbs because I can get them dirt cheap, I have thought many times about Ed Rosenthals theory... I guess theres only one way to find out...

I guess that I can't make up my mind to just go with one or the other... Currently I'm running a Solar Max Dual Arc 1K (600hps/400mh) and a 4 foot, 6 tube T5 fixture with (4) red and (2) blue tubes loaded. This is my first grow with the Dual Arc and everything has been going great. I do wish I had a strain to clone that I'd grown with the same setup before I got the dual arc but this is the first grow in this closet in a few years and the last few months with growing from seed and building some mother stock has been like re-inventing the wheel but at long last production is underway... whew!

Happy Growing!

 

[Growdude]

My point is according to the information provided a bulb which has a light emission curve that peaks at 3000k, would be far from ideal since that corresponds to wavelengths that are not absorbed.

Was this a typo? The wavelengths that are not absorbed are not used by the plant.

 

[BBFan]

For that matter, i'm not sure I am using the correct bulbs. I was just reading the forums and saw someone contradict what I had read earlier so I would like to set the record straight, and I will need some input.

1. According to greenmanspage.com/guides/lightguide.html and weedfarmer.com/cannabis/lightguide_guide.php

400-520 nm (promotes vegetative growth)

610-720 nm (promotes flowering and budding)

Found this online
Wavelength (nanometers) = 3,000,000 / Col temp (Kelvin)

400-520 is now 7500-5770 kelvin

610-720 is now 4918-4166 kelvin

This was said in the forums recently



Can anyone Confirm/Deny?

Now that I've seen the repartee back and forth, I see that you are looking at a more in depth analysis of Kelvin ratings as it relates to wavelength and the correct spectrum for optimum plant growth. Is that a correct assumption?

This is from SolarMax's description of their 600 watt HPS:

Solarmax 600 watt super hps bulb 95,000 lumens
2100 Kelvin gives these bulbs the ideal spectrum for flowering.

Reduced lamp sizes fit most horticultural lighting fixtures
Custom tailored spectral distributions
Highest output
All SolarMax lamps carry a full ONE YEAR WARRANTY

A maturing plant has dramatically different needs than a younger plant. As plants approach maturity they require less "Blue Light" and depend more upon radiation from the "Red" portion of the spectrum between 610 nm - 720 nm. Now is the time to utilize the superior "Red Light" output of the SolarMax HPS lamp. The SolarMax HPS lamps have been engineered to constantly deliver 10% more targeted "Red Light" energy to the maturing plant to promote aggressive flowering.

According to their statement above, I read that to say they believe the bulb operates at 2100 k with output in the 610nm - 720nm wavelength.

Are you questioning that an HPS operating at 2100k is not ideal, or not suitable at all? Certainly there is enough anecdotal evidence on this site (look at the grow journals) to indicate that 2100k is beneficial to stimulating flower growth.

Can you clarify your position?

 

[Etnavyguy]

Alright I will try to be clearer, if a bulb is rated at 3000 K then a good portion of the light produced should be at or near 3000 k. Go to wolfram apha, type in "3000 kelvin", half way down the page you can see that it correspones with a wavelength of 966nm. Go to one of the two sites that i linked to in the Origional Post. They are hard to see because i can't post links. For those who cannot go I will tell you what the link says:
610 - 720 nmThis is the red band. Large amount of absorption by chlorophyll occurs, and most significant influence on photosynthesis. (promotes flowering and budding)
720 - 1000 nmThere is little absorption by chlorophyll here. Flowering and germination is influenced. At the high end of the band is infrared, which is heat.

This makes more sense in the page.

What my question is, from the information I provided, it seems to me like most of the light generated from a 3000k falls in the band of little or no use.

Edit: en.wikipedia.org/wiki/File:Chlorophyll_ab_spectra.png (as additional proof) When using Flourescent I believe it would be better to use the 4100K bulbs for flowering not the 3000k.

 

[BBFan]

Again, certainly from the vast amount of anecdotal evidence on this site alone, it would be reasonable to assume that light in the temperature range of 2200k to 3200k promotes flowering.

IMHO the debatable point in your position is that there is a simple correspondence between wavelength as measured in nanometers and the kelvin rating of lights. But degrees kelvin does not relate to a specific wavelength, but rather the color resulting from a mix of wavelengths. So the asumption that "a good portion of the light produced should be at or near 3000 k" is not necessarily true. From my reading, a light operating in the 3000 kelvin spectrum consists of more wavelengths in the red spectrum (and also light in other wavelengths) which the plant absorbs through the photochromes zeaxanthin and phycoerythrin to promote, among other things, flowering.

Also, photosynthesis and reproduction are 2 different things.

 

[Growdude]

Was this a typo? The wavelengths that are not absorbed are not used by the plant.

No, I read it wrong

 

[charlesweedmore]

i use 600;W dual spectrum hps with 4 X 60W CFL bulbs. works like a treat