When to start feeding nutritients?

This is the perfect time to add some nutes for an autoflower - but only 1/4-1/2 the recommended dose as you need to see how she's going to tolerate them. And I also add in bloom nutes along with the grow nutes at this stage as well! Bloom nutes, with their minor amount of nitrogen, will not harm the plant and will get it ready for pre-flower which you should be in shortly. It's all going to depend on how your plants react to the nute line you've chosen... Just be aware that too much nitrogen will cause a lot of problems further on... Good luck!

She’s looking pretty healthy. Maybe avoid the nutes and start in with a quick tea. That’s my go-to for autos in the pre-flower stage. I like Cultured Biologix bloom tea right here. Good luck ✌️🏻💚🌿💨

I would definitely start now! And as Yoshi said, start small. 50% of whatever the manufacturer of your nutes says to do at this stage! Good luck!

you can start! 3 weeks is enough. maybe don't start with too many nutrients but she will 100% enjoy it! Good luck my friend! 🌳🌳