I was pro MG, now I'm not....They just seem too severe..Any local hardware or garden center will have a 20-10-10 sort of food for vegging & a 8-20-15 sort for flowering..(just basic) As for planting a soil less plant, it can be done....Use a very good drainage mix so as not to restrict the roots, as they've been use to easy intake.
what would be the best thing to use? ( in my country dont have a hydro shop i need to use the normal garden stuff until i get my sensi nutes)
Thats the same thing I've used for last 5yrs. 20-20-20 & 10-52-10 flower..I'm adjusting my nutes now...not so much the veg. food but I'm dropping the P in my flowering food.....around a 20-30.....20/20/20 diluted to about 25% or less of suggested strength should do it. Good Luck.