Can I use 20k MH for my plants ?

[joeyttk]

one of my MH just burnt itself out. Will my plant survive if I use 20k ? instead of my usual 14k

[Jervis]

one of my MH just burnt itself out. Will my plant survive if I use 20k ? instead of my usual 14k

I am no expert... but 20K seems a bit too "blue" for planted. Even 14K is kinda borderline.

[joeyttk]

do u meant it doesnt look good?

or it may cause algae ?

[Jervis]

do u meant it doesnt look good?

or it may cause algae ?

If I'm not wrong, the 20K bulb will have too much blue spectral value. A lack of red will stunt growth as red spectral value is very crucial to plant growth. And it is believed that excessive blue spectral value will promote algae growth.

In the end of the day... you can let your eyes be the judge. Personally don't think plants will look natural and green under 20K.

[joeyttk]

thanks Jervis. I am more into the fish, and the plants are secondary, as long as they do not degenerate into algae swine.

here's something of interest that I found, for general knowledge.

LED Grow Lights: 08/20/06

which says

"Most of the light capable of inducing the photosynthesis reaction is either red or blue. In other words, plant leaves mostly reflect green light, while they absorb red and blue with higher efficiency."

and

"The curve that results from plotting photosynthesis efficiency as a function of wavelength is named "Photosynthesis Action spectrum". It is the equivalent of the photopic curve for photosynthesis. The curve is typically double-peaked, with peaks around 420 nm (blue) and 670 nm (red) and a "valley" around 550 nm. The curve drops sharply below 400 nm and above 700 nm."

seems like blue is fine for growth, except that it may look surreal :) well... it means my plant will look like it is submerged 5meter below water

[joeyttk]

http://www.firstrays.com/plants_and_light.htm

[PeterGwee]

6500K to 10000K is fine. Anything more is more into marine region.

Regards,
Peter Gwee

[Jervis]

thanks Jervis. I am more into the fish, and the plants are secondary, as long as they do not degenerate into algae swine.

here's something of interest that I found, for general knowledge.

LED Grow Lights: 08/20/06

which says

"Most of the light capable of inducing the photosynthesis reaction is either red or blue. In other words, plant leaves mostly reflect green light, while they absorb red and blue with higher efficiency."

and

"The curve that results from plotting photosynthesis efficiency as a function of wavelength is named "Photosynthesis Action spectrum". It is the equivalent of the photopic curve for photosynthesis. The curve is typically double-peaked, with peaks around 420 nm (blue) and 670 nm (red) and a "valley" around 550 nm. The curve drops sharply below 400 nm and above 700 nm."

seems like blue is fine for growth, except that it may look surreal well... it means my plant will look like it is submerged 5meter below water

Your plants need both red and blue for healthy growth.