hi cypher....
I would not start using nutrients in MG soil for at least 2 months...
I would also not start feeding seedlings or clones (in other soils) as a general rule for the first 7-14 days
I have seen many nice plants grown in Fox Farm and MG with no nutrients added.. They were flowered early and were grown in 3 gallon containers..
water pH is KEY..
iloveyou