Begin harvesting parsley when it produces leaf stems with three segments. Harvest the larger leaves at the outside of the plant first, leaving the new, interior shoots to mature. To encourage a bushier parsley plant pick only the middle leaf segment of each main leaf stem.
To keep parsley fresh, store freshly picked sprigs in the refrigerator with the stems in a jar of water covered with a plastic bag. Another way is to sprinkle the leaves with water, slip them into a plastic bag, and refrigerate. Both methods keep parsley fresh for 2 weeks.
Freezing is the best long-term storage method. Parsley freezes well chopped up and stored in plastic bags or blended in water or stock and frozen in an ice cube tray. Remove the frozen cubes and store in sealed plastic freezer bags. Frozen parsley will keep for 6 months.
Parsley also dries well, although it loses much of its flavor. Place leaflets on a cookie tray, set it in an oven preheated to 400°F, then turn off the oven, and leave it undisturbed overnight. This is best done on a day with low humidity. Experiment with drying it in your microwave oven. Store dried parsley in an air-tight jar. It will retain some flavor for 1 year.