# Kelvin Question.



## Icex420 (Dec 29, 2009)

What would be ideal for flowering with hps?

2000k .... 2100k ..... 2200k  etc?


2k?


----------



## pcduck (Dec 29, 2009)

I think most use 21k that is what I use for flower


----------



## Icex420 (Dec 29, 2009)

Alright. thanks.

Any other info?


----------



## BBFan (Dec 29, 2009)

An average hps can range in kelvins from 2100 to 3000.  And they'll all give you pretty much the same results.

You should actually look more for output in terms of spectrum.  There are some enhanced spectrum bulbs out there, but not sure if they're worth the big bucks they go for.

Good luck in your search.


----------



## DonJones (Jan 1, 2010)

BBFan,

The Kelvin temperature is measure of spectrum that is more meaningful than wave length which is the other measure.

As to the enhanced/conversion bulbs, if you really research them I think you find that they are hokum.  The Agrosun ones do not seem to accomplish anything that research the temperature of the bulb before you buy and select one with as high a temperature as practical for HPS and as coll as practical for MH.  For instance the Agrosun MH conversion/enhanced HPS bulb lists and Kelvin temperature in the close to 3000 range, which is within the upper limits of commercial normal HPS bulbs.  Reputable commercial producers list their kelvin temperatures for each model of a given bulb that they sell.  Sylvania for example makes HPS all the way across the range, and buying one near the same temperature as the Agrosun MH conversion/enhanced bulb will nearly always cost you much much less than the Agrosun.  And I can almost guarantee that the AGROISUN bulbs are produced by one of the other manufacturers because do you really think the grow light market is large enough to support that large of an investment when they aren't going to get anywhere near all of the market in the first place when you consider the cost of setting up a bulb manufacturing plant.

In case you didn't catch my opinion here it is clearly stated -- save your money and buy either a dual mode ballast or a ballast for which ever type of light you want.  If you are stuck with trying ot make do with one type ballast, then start researching the offerings of the major manufacturers for that type of light and then buy the particular part number that closest meets your needs.  Usually that is as high a temperature as you can get for HPS and as low a temperature as you can get for MH.  It seems like more and more researchers are suggesting that a mixture of HPS and MH is best for both vegging and flowering, with the percentage of each varying depending upon which you are using it for.  I'm seeing a lot of knowledgeable growers supplementing their HPS light with blue floros and their MH with red floros rather than just choosing between one or the other.  That is one of the other advantages of floros is the wide availability of color temperature tubes available for a single fixture -- you can get almost any temperature you want by mixing or matching tubes and can change that result without changing the fixture or the ballast.  Also, because they run so much cooler, you can keep them MUCH closer to the plant increasing the efficiency of the light the plant gets and uses.

Great smoking!


----------



## BBFan (Jan 1, 2010)

DonJones said:
			
		

> The Kelvin temperature is measure of spectrum that is more meaningful than wave length which is the other measure.


 
DonJones-

I'm sorry, but you are incorrect in your premise. Kelvin is not a measure of spectrum. Can you explain to me the difference between 2100k and 2700k and their respective effects on photosynthetic reactions without referencing spectral output?

Kelvin is a measure of temperature that is used to measure many things, not only light. Light spectrum is measured specifically in nanometers and as such is much more effective in determing efficacy of a light source in relation to plant growth. While kelvin may put you in the right neighborhood- it can be achieved by combining varying amounts of light in opposite spectrums; nanometers will determine the ultimate effectiveness of growth.

A conversion bulb and an enhanced spectrum bulb are two completely different things when referring to indoor growing with HID's.

A conversion bulb is a bulb that can operate using a different ballast, usually at a cost of output. I use MH ballasts and a HPS conversion bulb that will operate in my MH ballast.

An enhanced spectrum bulb is a bulb that puts out an enhanced spectrum, as the name implies. Whereas a standard MH bulb may operate in the 390nm to 500nm range, an enhanced bulb will put out some wavelengths in the 640nm to 660nm range, albiet in lesser amounts. I do not use Agrosun bulbs, but I do use SunMaster bulbs, and that is the spectral output of my enhanced MH bulb- I'm looking at the package as I write this.

My recently harvested comparison grow using enhanced spectrum MH versus standard MH and standard HPS resulted in some noticeable differences in growth, but I need to replicate conditions on my next grow to see if I achieve similar results before I can draw any sort of reasonable conclusions, though most likely it will take a few more grows. So as far as being hokum, the jury is still out until I can measure results from my next grow. Maybe you know something I don't. Perhaps the measurable difference will ultimately be insignificant for our applications- our goal here is, after all, achieving optimum results relative to investment.

Your comments regarding the use of flouros in the context of the OP's original question is really not relevant and should be discussed in another thread.

Also, your statements involving contract manufacturing are irrelevant. Proprietary technologies exist and are commonplace in contract manufacturing. Certain aspects of my business are involved in OEM contract manufacturing whereby products are produced in identical environments with different specifications resulting in measurably different end products.

Thank you for your comments and perspective- I did catch your opinion, I'm just not yet convinced that I agree with you. I do however stand by my initial statement to the original poster regarding the differences between 2100k and 3000k lighting and photosynthetic activity and response.

Happy Growing!
-BBFan


----------



## DonJones (Jan 1, 2010)

bbfan,
Happy New Year! 

Obviously your expertize exceeds mine.  Just as obviously you want to argue and I don't play that game.

Good smoking.


----------



## Icex420 (Jan 1, 2010)

DonJones said:
			
		

> bbfan,
> Happy New Year!
> 
> Obviously your expertize exceeds mine. Just as obviously you want to argue and I don't play that game.
> ...


 
Don why is every post i read by you some like otherworldly explanation to something that isnt even true? Let me rephrase that. Stop giving out info you know is incorrect.

????


----------



## Icex420 (Jan 1, 2010)

BBFan said:
			
		

> DonJones-
> 
> I'm sorry, but you are incorrect in your premise. Kelvin is not a measure of spectrum. Can you explain to me the difference between 2100k and 2700k and their respective effects on photosynthetic reactions without referencing spectral output?
> 
> ...


 
And BB, Thank you for answering my question. Basicly you say the only thing thats going to make a 2200k a better bulb than a 2300k is if its an enhanced spec. bulb.

You actually taught me a couple things in that post. Thank you. Unlike Donjones. Quite the opposite. I was actually allmost angry i read his entire post to find out it was just a bunch of blah blah blah.


----------

