Parsley (Petroselinum crispum) is a biennial grown both for its leaves and, in the root-parsley form, for a white, parsnip-like root. Sow directly outdoors from March to May; germination is notoriously slow, taking three to four weeks, so soaking the seed overnight and keeping the soil moist helps. It grows best in deep, loose, humus-rich soil in sun or partial shade, and should not follow carrots, dill or celery in the same bed. Thin seedlings to about 10 cm apart. Harvest leaf parsley by cutting the outer stalks near the base, leaving the heart to regrow; the leaves keep their flavour better frozen than dried. Root parsley is lifted in October, before hard frosts, and stored like carrots in damp sand. Flat-leaved varieties have a stronger flavour, while curly ones are hardier. In the second year the plant flowers and sets seed and the leaves become coarse, so sow fresh parsley every year.