look mate dont add nothin get it out that soil first. ! get a 3 gallon pot . go to your nearesty home depot and get some soil with a ph of about 6.5/6.8 . when you take it out the pot with that shit .M.G soil very gently hold the stem and slap around the side of that shit soil till most of it falls away.the root mass on that plant aint going to be bad beleave me i done this for a freind last year.Once you have shakin off most of that shit soil then transplant it into a 3 gallon pot and fush it through . Then give it some nutes starting of with a low dose building up to the stated dose high in nitrogen but not to low in p,k. like canna terra vega, some superthrive and cal mag = and then watch your baby grow . then it will be fine and this should be led an example of what damage that mg soil can do.Garden i dont know how you do it my freind you are a genious.( he has used mg with great results lol). hope this helps the postman