In hairy root bioreactors used for the production of valuable secondary compounds, mass transfer is an important factor in product optimization and growth. Because most root bioreactors are liquid submerged, the system must have sufficient liquid mixing to achieve adequate mass transfer. Liquid mixing in shake flask cultures was studied to determine mixing times. In addition, to further study the effects of root hairs on mixing in shake flask cultures, mixing time data for hairless roots was compared to a root species possessing profuse root hair. The results directly contradicted the standard hypothesis that cultures at similar fresh weight densities without root hairs have faster mixing times. The proposed explanation for this phenomenon is the nonuniform tissue distribution within the flask. Because previous researchers observed faster mixing times in larger sized flasks, the limiting density of shake flask cultures was found to see if the fast mixing times could be used to characterize growth potential. Although results were inconclusive for the present experiment, improvements are suggested for obtaining more definitive data through modifications of the original experimental procedure.