Looking very good man! Awesome green growth and some nice fat leaves is always a good sign of a healthy plant.
What should you do to maintain that growth?! I would say just keep doing what you are doing, it is obviously working great! And as you mention yourself, make sure to transplant it into a bigger pot so it won't be limited by the size of the roots. I used to grow in 11L pots and now I am using 25L because I am going for 4 plants in a 4x4 tent instead of 9. Maybe this is just a matter of genetics, the sample size is too small to say anything definitively, but the growth I had after I switched to 25L is insane, so maybe pot size is more important than I used to think or maybe not?! Either way, that would be my advice if you wanna go for a really big plant, then go for a really big pot too.
I have never grown anything outside, so can't really give any comments on that.
The seeds I grow myself is from a company called SubSeed, so it is not from Dutch Passion. However, I do have some White widow in the flowering tent right now from Dutch passion going on week 10. Can't say I had much luck with them in terms of germination rate, but the ones that did germinate sure is doing good.
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