Learn how to harvest arugula like a pro! Arugula, or rocket or rucola, is a versatile leafy green with flavor. When it comes to harvesting, timing is critical. Stay until the leaves are approximately 6 inches tall for the best flavor. Using clean scissors or garden shears, snip the outer leaves about an inch above the base of the plant. This encourages new growth and allows you to continue harvesting throughout the season.