Re: What does 6500K actually provide for plants?
6500k is a convention that the community has come up with. It has the property of looking fairly pleasing to the human eye and still having decent efficiency for a light (LEDs are generally more efficient if they are higher kelvin). I have a very large range of plant lights from 4k to 10k all of them grow plants just fine. If I was to go any lower the light would look awefully yellow and any higher and it would be fairly blue and washed out looking. Now there could be slight efficiency gains from certain spectre for certain plants but unless you are trying to farm one specific type of plant I doubt this will be really helpful to you. It's hard to know what to answer though without knowing what you want to achieve. You can grow plants in just rend and blue that looks like purple, you wouldnt want that for a show tank though, and you can spend a ton of money on a "high" "full" spectrum light to have the best color reproduction, you can even customize a light to your liking.