[Homer]

I have used lights ranging from 3000K to 5000K and found that the intensity seems to matter more than the Kelvin rating for growing plants.

I have orchids routinely bloom in terraria with only 3000K bulbs, and I don't see the point of spending more money on the 5000K bulbs when 4100K bulbs tend to cost around 1/2 the price (as far as compact fluorescent bulbs go). However, the light is more yellow on the low end, and I know that bothers some people.

 

[Homer]

Danny,

It sounds like you must be using metal halide bulbs to be utilizing lights in that spectrum. I'll bet that your growth is extremely bushy, especially with the intensity of light that metal halide bulbs put off. However, I thought that anything over the 10,000K range was in the actinic range and more suited for saltwater type growth . . . and pretty expensive, to boot.

Let me know more about your setup, I'd love to know the specifics if you have the time, and what plants you are growing under those lights.

Thanks,