im using the same medium its really good starter soil but no real NPK value as its so low in all the nutes. from what ive researched its more of a soil that allows u to control the abundance of nutes and the strength. im on week 4 of life week 1 of flower i didnt use veggie nutes thinking they would not need it as the time before flower is short boy i was a bit wrong. a good sign to start using them is the yellowing of the cotyledon. working on a mix and im using 2 tbsp of mother earth super tea and 1 tbsp of molasses to a gallon on tap water. good luck!