Causes of Parsley Bolting

Life Cycle

• Parsley is a biennial if left to its own devices. Many gardeners grow it as an annual, either because of unfavorable climate or to avoid the inevitable bolt that occurs during the second year. Being a biennial means that the parsley plant only lives for two full years before dying fully. That said, bolting is a natural response to impending doom -- the parsley is simply passing on its DNA to future parsley plants.

Premature Bolting

• Sometimes parsley bolts prematurely. This is when gardeners become frustrated. Because it often takes three to six weeks for seeds to germinate and about 70 days for parsley to begin to be harvestable, a premature bolt is not a good thing. Exposure to temperatures below 45 degrees Fahrenheit for one to two months prior to a warm-up is the primary trigger for parsley to bolt.

Prolonging Harvest

• Purposeful parsley care can prolong the harvest well into the second growing season. Begin harvesting parsley from the outside leaves inward. Continue picking leaves even into the second season to discourage bolting. If you see a flower stalk begin to form, pinch it immediately. The denuded plant will continue to focus efforts on growing new leaves as long as possible because seed formation uses a great deal of energy.

Beyond Soup

• Parsley is a useful plant, attracting beneficial insects as well as providing tasty herbs for a variety of dishes. Swallowtail butterflies are particularly drawn to parsley flowers, attracted by the furanocoumarin in the forming seeds. Swallowtail larvae can process this extremely potent chemical that often kills competing seedlings and turn it into a dietary delight. As adults, they have the ability to spread parsley pollen while engaged in their reproductive cycle.