At the moment i am using top soil that i bought in my garden center.
It is sterilized.

I was thinking it would be better to continue using this soil and feed the plants myself.

Much easier to monitor how much nutes they have.

I live in Ireland so we have different brands.

I have seeing plent of 20 20 20 feeds.Would this be okay using 1/4 1/2 3/4 then full strength?