Prune dead or diseased flowers and leaves with pruning shears and discard in the trash. Make sure to sterilize pruning shears with rubbing alcohol after handling infected foliage.
Cut the arugula's white flowers with the stems intact and transplant them into the soil approximately ¼ inch deep and 12 inches apart in rows for future propagation.
Cut arugula stalks to about 2 to 3 inches from the ground. Place leaves into plastic bags for future consumption and discard the stalks in the trash.
Fertilize around the base of pruned arugula plants with liquid fertilizer or bone meal to promote new growth. Cut back the arugula every two to three weeks during the summer until the first fall frost.