Extend the life of cut flowers by following this simple recipe. Pour 2 tablespoons of white vinegar in the vase and add 2 tablespoons of sugar. Fill with water; stir until the sugar dissolves. Arrange your flowers and enjoy! (The Vinegar inhibits mold and bacteria growth, while the sugar gives the flowers a little nutrient boost.)
Source: Do It Yourself Magazine Vol. 16 Issue 1, p. 16.