I used my lux-o-meter (an app for my smartphone) and under the light it said lux were equal to sunlight (I don't remember the numbers).
I saw one leaf has already got longer, not much but I can see clearly the difference since it was eaten by one of my cat, it's the only leaf left and it was really small. I guess the lights should be closer as possible. LEDs stay cool so no danger of burning leaves.
