Lighting CFL color spectrum question

[Sir Chiefs a Lot1]

So I'm going to be starting my first grow in the next couple of weeks, and I went out and bought 12 23w CFL bulbs. 8 of which are 2700k and the other 4 are 5000k, which I will be running all 12 at the same time for the whole grow. So my question is, will the 4 5000k bulbs be OK to help during veg? The reason I got the 5000k and not 6500k is because of the price difference was more than I could afford for my budget.

 

[happily]

There not as strong of a blue but they'll help. I have the same because it was all I could find

 

[namvet25]

They will work just fine.

 

[gradolabs]

I'll post a picture that explains color temp and its relation to, say... standard color space. Two seconds.

And since they made the colors really opaque I'll post the picture that shows how the higher the color temp the more blue biased the cfl will be.

 

[Sir Chiefs a Lot1]

Thanks for the help everyone. I greatly appreciate it. Hopefully with having 276w of CFL's, I'm hoping to have a decent amount of growth and yield.

 

[Balarama]

If I may add a few words...May sound boring

Theoreticaly speaking a light source's temperature description of colour should match the black body radiation at the given temperature...for example, a bulb with a 6400K spectrum should emit a light curve of a black body, heated at 6400K.
However, cfl's are not black bodies, they are basically electrically excited gassous tubes in which the process of light emission is very different from the black body(heat radiation). Because of that, the tubes are filled with coloring chemicals which control the proportion of the most prominent spikes in the mercury spectrum and work as a kind of filter to the emitted light. This means the overall color of the lamp is a clever proportion of some specific wavelenghts of light in order to match the human eye's perception of the supposed black body radiating.

What's the point of that? I think it's the lack of "supposedly-be-there" wavelenghts because of the nature of gas light emission. The temp color lables are fundamentaly deceptive in cfl world, but handy because we deal with light with our own eyes, so the eyes can be tricked without realizing their own limitations

.....

I measured some cfl's spectrums and found out that the 2700K lamps have veeery little blue light and are more than 6x less adequate for vegetative growth(6x less blue light compared to 6400K). The 6400K however, has little less red, but overall should be more suitable for flowering than the 2700K's are for vegging.

Based on that observation I would always switch lights when switching cycles and would probably look for higher than 6400K color. A mix of 6400K and 8000K* would be of benefit during veg grow, IMO.


*not sure really, would have to measure

 

[midowo]

If I may add a few words...May sound boring

Theoreticaly speaking a light source's temperature description of colour should match the black body radiation at the given temperature...for example, a bulb with a 6400K spectrum should emit a light curve of a black body, heated at 6400K.
However, cfl's are not black bodies, they are basically electrically excited gassous tubes in which the process of light emission is very different from the black body(heat radiation). Because of that, the tubes are filled with coloring chemicals which control the proportion of the most prominent spikes in the mercury spectrum and work as a kind of filter to the emitted light. This means the overall color of the lamp is a clever proportion of some specific wavelenghts of light in order to match the human eye's perception of the supposed black body radiating.

What's the point of that? I think it's the lack of "supposedly-be-there" wavelenghts because of the nature of gas light emission. The temp color lables are fundamentaly deceptive in cfl world, but handy because we deal with light with our own eyes, so the eyes can be tricked without realizing their own limitations

.....

I measured some cfl's spectrums and found out that the 2700K lamps have veeery little blue light and are more than 6x less adequate for vegetative growth(6x less blue light compared to 6400K). The 6400K however, has little less red, but overall should be more suitable for flowering than the 2700K's are for vegging.

Based on that observation I would always switch lights when switching cycles and would probably look for higher than 6400K color. A mix of 6400K and 8000K* would be of benefit during veg grow, IMO.


*not sure really, would have to measure

Goood information here...
So you are saying that 2700K are not good for vegging?

 

[GoAuto6]

2700 all the way through works just fine.......

 

[Balarama]

Goood information here...
So you are saying that 2700K are not good for vegging?

I actually speak without experience, only on a theoretical basis...but from what I read, the better option should be the 6500K spectrum and even 9000K or 10000K if available. For true facts the spectrums should be measured and compared to the clorophyll(A and B) absorption spectrum curves.

There are however a few catches.
I presume the vegging plants with optimal spectrum should grow more bushy and not so stretched, which can have its downsides. Another catch is the proportion of red spectrum needed for vegging(have no real data of that), which can be better provided with a 2700K bulb.
So if we put all these pieces together, one should have a mixed spectrum during growth, in my opinion a good setup should look like that(an example):

Veg - 4 lights 10000K + 4-8 lights 6500K + 2-4 lights 2700K*optional (total approx. 250W or more)
Flo - 12-20 lights 2700K, + UVB bulb(aquarium/lizard purpose) last two weeks (total CFL around 250-500W + few W LED UVB)


I'd probably make it like that ...but as GoAuto said, they should be fine(but not great, I think).

 

[GoAuto6]

If it where me I'd buy equel of both, and test it for my self.... and have fun, mix it up find out what works for you........