Quote Originally Posted by divestoned
unlike ppm(which can vary by strain or particular conditions) PH determines the plants ability too absorb and process nutrient.there for the 5.5-6.8 applies to any method,although as you say soil will maintain the higher end w/out negative effect.

P.S. whether in veg. or bloom i run my ph at 6.0 (hydro)
Wait right here(book in my lap) it says that primary nutrients cut off below 5.5 pH, It's not optimun but it works.