sound a bit like 'miracle goro' kinda soil, which i personally use. only issues with miracle gro , and i suppose this covers any nutrient rich soils, is the danger of nute burn, especially in very young plants. i start with a 'no nute' seedling and potting soil and after around two weeks when the plant is maybe 6 to 8 inches in height i put it in my next pots, my mix is always the same ; around 705% soil, 25% perlite and 5% vermiculite. i usually dont need to give them any food for around the next 3 to four weeks and when i do i start with 1/4 strength; for me that means 1ml per litre using biobizz grow nutrients, i will usually only veg for another weeks or so , by that time they will be around 30" in height, sumtimes only 24", then i flower them.