Vinegar is a solution containing acetic acid, an organic acid produced though the natural fermentation of plant materials containing sugars. Vinegar has been identified as a potential organic herbicide, but more information is needed to determine the influence of application volume and use of additives (adjuvants) on weed control. Acetic acid acts as a contact herbicide, injuring and killing plants by first destroying the cell membranes, which then causes the rapid desiccation of the plant tissues. Household vinegar typically contains 5% acetic acid. Vinegars with acetic acid concentrations of 11% or greater are available commercially, but inappropriate use of these products can burn the skin and cause serious to severe eye injury, including blindness. Field research was conducted in southeast Oklahoma (Lane, OK) in 2005 to determine the effect of application volumes and adjuvants on weed control efficacy using vinegar with a 20% acetic acid concentration. The factorial experimental design included vinegar at three sprayer application volumes (20, 80, and 160 gpa), three adjuvants (none, orange oil, and non-ionic surfactant), and two weedy-checks. Visual weed cover and control ratings were collected throughout the experiment. The experiment had very high weed densities with multiple species of grass and broadleaf weeds. Vinegar was more effective in controlling broadleafs than in controlling grasses. When averaged across adjuvants (none, orange oil, and non-ionic surfactant) weed control increased as application volumes increased from 20 to 160 gpa.