Week 3 seems fine, i made a slight mistake by giving it too much nutrients at a point and got some nute burn (small burnt tips on leaves) so i calmed down with the nutrients and it's still growing healthy. Let's see what we have coming for week 4..
If it is an autoflower ;then surely once it preblooms now ; there is not going to be much difference in its size and thus lower yield. It may be a mutant or the light is not sufficient and so it remained small.
plants stretch at night. since they're under 24h, they don't. i'd go for 20/4 at least. regarding blooming phase: it won't be long in coming. if it doesn't within the next 2 weeks, switch to 12/12. cheers, mate! :)
Yeah I'm growing Barneys Zkittlez OG Auto mate and my girl as well was a late bloomer but as you can see mine got over her shyness as well will yours =) Also, I am currently using 305 Watts(wall draw) as well. Good luck !!!
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