Parsley

Identification and origin

Petroselinum crispum belongs to the Apiaceae, the carrot and celery family. It comes from the Mediterranean, from Greece to the northwestern Balkans and northwestern Africa (Morocco, Algeria), and has become naturalized on nearly every continent.

Parsley is a biennial. In its first year it forms a rosette about 12 in tall of dark green leaves, three times divided into toothed leaflets, on long, thin, hollow stalks. In the second year a 2–3 ft stem carries umbels of tiny greenish-yellow flowers that attract butterflies, followed by small ridged seeds, and then the plant dies. Once it flowers, the leaves turn tougher and lose their flavor.

Curly parsley (var. crispum) makes a low clump 8–14 in tall with tightly crinkled leaves and a mild taste. Flat-leaf or Italian parsley (var. neapolitanum) is taller and lankier, with flat leaflets richer in essential oil and a stronger flavor; cooks prefer it. Hamburg parsley (var. tuberosum) is grown for its white, parsnip-like root. Common cultivars include ‘Moss Curled’, ‘Bravour’, ‘Envy’ and ‘Banquet’ among curly types, and ‘Titan’, ‘Argon’ and ‘French’ among flat-leaf types.

Parsley is often confused with poison hemlock (Conium maculatum), which is highly toxic: never gather “wild parsley.”

Light

Parsley does best in sun, with six hours of direct light a day, though it accepts light shade. It prefers cool summers and can wilt in hot, humid weather; move containers into the shade during very hot, sunny spells.

Indoors, aim for four to six hours of direct sun at a south- or west-facing window. It tolerates a little less light than thyme, but in dim conditions it turns spindly. Long, floppy stems mean it needs more light: add a full-spectrum grow light on a timer for twelve to sixteen hours a day.

Watering

Parsley wants soil that stays evenly moist and copes poorly with drought. Feel the soil and water before it dries out deeply, soaking the whole root zone. Waterlogged soil, on the other hand, drives out air and suffocates the roots.

In containers the mix dries out very quickly in warm weather, so check it more often in summer. In the garden, a light mulch of shredded leaves or grass clippings holds moisture and keeps weeds down.

Potting mix

Parsley needs richer soil than most herbs: moist, fertile, high in organic matter and well drained, with an acid to neutral pH. Before sowing, loosen the soil and work in well-rotted compost if it is poor or drains too freely.

For a container, choose one at least 10 in wide and deep, with drainage holes, and fill it with a peat-free multipurpose mix. Feed potted plants with liquid fertilizer at half strength every three to four weeks outdoors and every four to six weeks indoors; garden plants need only one or two feedings per season.

Temperature

Parsley is winter hardy to USDA zone 5 and is grown as an annual as far as zone 11. Its leaves stay green down to about 21 °F. In the garden the foliage dies down in winter and the crown might regrow in spring; a cloche or cold frame extends the harvest. Bring containers indoors before temperatures drop below 30 °F.

Indoors it likes it cool: 64–70 °F during the day and 55–61 °F at night.

Repotting

Parsley grows a taproot that resents disturbance, so the simplest approach is to sow it right where it will grow, in the ground or in a container. If you sow in cell trays, transplant when seedlings reach 4–6 in, without breaking the root ball, at the same depth and 6–12 in apart, after hardening them off gradually.

For winter harvests, dig up a plant in fall, pot it in fresh mix and keep it in a cool, very bright spot; replace it with young plants in spring. Supermarket pots are packed with crowded seedlings and are meant for quick kitchen harvests.

Pruning

Harvesting is the pruning. Start when the plant is about 8 in tall. Cut one or two whole outer stems at a time, close to the ground, and the center keeps producing. Cutting only the tops of the leaves and leaving the stalks makes the plant less productive. Remove lower leaves as they yellow.

Parsley is best used fresh; washed and bagged, it keeps in the refrigerator. Freeze it chopped in an ice-cube tray topped with water, or dry it in bunches hung in a warm, dark, airy place, though it loses some flavor. In the second year, keep the plant only for its seeds.

Propagation

Parsley is grown from seed and is slow to sprout: two to five weeks depending on seed freshness, sometimes six. Soak the seeds in warm water overnight, up to twenty-four hours. They germinate from 39 °F, but much better between 50–84 °F, with an optimum near 75 °F.

Indoors, sow six to ten weeks before the last spring frost, 0 in deep, in cells of moist seed-starting mix, in a warm, bright place. Outdoors, sow from mid-spring to late summer, then thin. Keep the soil moist until seedlings appear; they look like blades of grass. Sow small batches every few weeks. A second-year plant sometimes reseeds itself.

Common problems

• Flowering, bitter leaves: the plant is in its second year; sow again each season.
• Seeds fail to come up: old seed, cold and wet soil, or soil allowed to dry; be patient.
• Spindly plant indoors: not enough light.
• Leaf spots: Septoria leaf spot (Septoria apiicola), the most common disease.
• Distorted shoots, weak plant: aphids; a spray of water is often enough.
• Large caterpillar on the leaves: the parsleyworm, larva of the black swallowtail (Papilio polyxenes). Young ones are black and spiny with a white saddle; older ones are green banded with black and yellow spots, up to 2 in long. When disturbed, they push out two smelly orange horns. Handpick them, or plant a few extra plants to share.
• Foliage scorched in patches: celery leaf miner; carrot fly also attacks parsley.
• Young plants chewed: slugs and snails, less of a problem in containers.
• Others: flea beetles, leafhoppers, tarnished plant bugs, carrot weevil; stem rot.

A single symptom can have several causes: check light, watering, heat and the age of the plant before acting.

Toxicity

Parsley is listed as toxic to dogs, cats and horses. Its furanocoumarins can cause photosensitization, with sunburn and skin inflammation, but only after large amounts are eaten. In people, toxicity is rated low and works the same way; the plant does not cause contact dermatitis. The fruits and seeds are toxic to birds. If a pet eats a large amount, call your veterinarian.