those big netpot tops are nice, but I use 3..5" netpots...sometimes 5". If you grow a big plant, and you will in a bubbler...you will most likely have to support the stem at some point. I wouldn't waste my money on large netpots, or all the hydroton you will need to fill them...Stay small and if necessary use some string to hold plant erect after it get's 4-5 feet tall. peace