it's a kelvin value. Color temperature of he light the bulb gives out. 6500k is the ideal color temperature for vegging. & 2700k is best for flowering.
So it's a sprout but you want to avoid transplanting so keep in mind that when she gets big enough you need about a gallon of dirt for every foot of height she's got on her. 5foot plants need about a 5gallon pot. I let my clone go from rockwool to 5gallon pots with about 12inches of hieght. So get two pots. Let 1of them go real mega dry & then fully water 1of them. There will be a weight difference that will be easy to distinguish on instinct & common sense. So lift your bucket once a week. & you'll feel if the pot is heavy or lght. & if it's dry once a week then water once a week or as often as the pot goes light.
Since it's a sprout keep the dirt moist but not soaking wet. & no nutes untill it has at least 5nodes on it. 1/4 the strength of the recommended nute feeding dosage. As she gets big gradually increase the nute feeding potncy.
After she's grown a bit don't over water or keepthe soil heavy wet. You want your dirt to dry as the air that leaks into the soil carries oxygen your plantsroots can use to breath a bit. Wet dirt suffocates your plants roots & she will let to know she's stressed out.
& the 1st part of your plants life is over. Germination. She's got almost a couple of nodes on her & she is developing roots now. So light is a must so she can go on with a healthy photosynthesis process. Keep the light as close as possible without heating her up.
Check me on anything I missed