giving a cactus flora nova nutes.

i got a cactus in a pot outside. the cactus is a half foot tall and 4 inchs wide. it is in a small catcus pot like 6 inchs around and 6 inchs high. Came that way. It was a gift. I keep it dry but gave it some veg nutes. a mild veg mix. some superthrive too. think it will grow? i have heard some advie the pot is ok. i doubt that, any soil advice so i can repot? Should i go heavier on the flower or the veg. i saw some online cactus fertiliaer and it was high in the P and I know little about soil and am learning nutes on the whole better. P is flower. I still beleive a veg mix accoridng to flora nove feeding charts will be better.

When I want to move cacti tio larger pots, I dry out the medium so it slides out of the old pot. Then place it in a larger pot after loosening up some of the soil around it.
Now fill the open spaces with suitable well draining medium, and allow the roots to go there when they feel the need.

thank you/========