I live in Hawaii so I dont know if the weather matters but I grow my lemon grass in my E+F growbeds. I usually start them there (90% survival rate vs 50/50 sin soil) and then transplant them to soil and water with drip lines. They can get big, like 3' in diameter, so leaving them in a GB would take up alot of space. Although you could put them into a half barrel by themselves.
I also grow my lemongrass in tropics (Java). have had good luck with mature clumps transferred into gravel media; it thrives all year, although rainy season slows growth.