Fish-n-beer-guy
Aquarium Advice Apprentice
So I've heard a bulb fir planted aquarium should be 6500k. True or false? If true does it matter if the bulb is specific for plant growth or can I find a bulb at my local hardware store that us 6500k?
K stands for Kelvin, which is the color temperature of the bulb. A plant can use light ranging anywhere from 5,000-10,000K in photosynthesis. So what you've heard is partially true. It could also be anything else in the range.
BillD already explained why we don't use Kelvin as a true indicator for plant use. You are going to confuse people.
Plants don't use light in any particular Kelvin range. They use light in the 350 to 700nm range. You have to look at the lights spectrum, not it's Kelvin rating.