Royal Queen Seeds, Quick One

Is it the lights that make it grow so fast ? Mine is week 3 too and is tiny compared to yours.

I think i've never seen a Quick One as beautifull as this one.

18, 20 or 24 hours of light all work for autoflowering strains (like yours), meaning that they go into flower regardless of the day lenght. You are in the pre flower phase, where plants go into rapid growth while making room for flowers. Force feeding will lead to nute burn, not more buds. If you want to reach all the plants potential, then you should transplant it to a bigger pot, 1 liter is quite small, think 10 liters, although at this point is kind of late.