when is the best time to start nutrition?

Also, use a root stimulator from day 1 in Coco . Seedlings require around 250 PAR for optimised growth . Which works out to 11k lux on my meter . That's under white light LED chips with a 3k colour temp.

In Coco I start feeding a small dose of calmag and base nutes. Like 0.5 EC. then give more as they grow. I remember my first grow I was told not to feed for the first 3 weeks. My seedlings didn't grow and nearly died lol now I feed nutes I have small bushes by 3 weeks. There is enough in the cotyledons for about 5 to 7 days in coco. After that they need nutrients.

I give very light nutes. Like sensi cal mag. Since i'm in coco. I add less then 150ppm total. To my distilled water from dehumidifier to water my weedling.. . I don't exeed this. I'll sloly raise for week 2 around 200 early on 250 later. And if you are in soil. Then i would just top spinkle (powerder after a watering and not tilt it now) or top dress with compost since soil has the habillity to hold nutrient

around the 2nd week you could start using nutrients at low dosages. earlier than that maybe some root stimulators and similar products. is the max light a nutrient? if so please post a link, if you are asking how much light can she take at this point, probably around 150-200 PAR. good luck and stay lit growmie.