It's week 6 and still vegetation.
Nutrition: for 5 liters of water I used 4g PF, 2g Mineral Magic, and 8ml Diamond Nectar. I don't know what is wrong but the TDS meter shows PPM 600 which should be not enough, but the plant is growing well.
Finally, I put in powerful lights instead of the small ones. I'm so happy that it is already time to set up the net and fill every corner of my box with the plant. I'm going to keep it in vegetation for at least one more week.