depends on what you are trying to eradicate, 2% is fine for most weeds, grasses, if you are like me you have blackberry briars, chinese privets, etc mixed in and a few little cedars, I mix these 3-4% or hit it two separate times with 2% then spot spray any woody stem survivors with a 5%. word of advice , don't fill it up to 30 gal if unless you are certain it won't leak, not a good feeling with roundup going down your back on your ATV, emergent situation, I always leave 5 gal out from the top!
