Are “Grow-Rocks” REALLY necessary or will just plain old rocks work?
I am VERY new to the hydroponics world and i have a question maybe you can help me with. i have set up an 11 plant ebb & flow system using PVC pipes, a storage bin, and some 2L bottles. i plan to use small pea gravel for my growing medium, i have seen “Grow-Rocks” advertised on websites but are they REALLY necessary or will just plain old rocks work? any help you can give would be much appreciated. ~ Ryan Dear Ryan, One of the oldest medias used by hydroponic growers was “pea gravel”. This is usually washed river rock about 1/4 – 3/8″ in diameter. It should work fine – but will be heavier weight. You want to avoid crushed rock. The crushing process exposes new stone surfaces that may release minerals into your solution. I suspect that the “Grow Rocks” are a form of volcanic pumice. This would be a lighter weight than “pea gravel”, but would be more expensive. Another media that may work is perlite. This is a volcanic sand that has been heated until it “pops” like popcorn.
