Dill

Identification and origin

Anethum graveolens belongs to the Apiaceae, the carrot family that also includes parsley, cilantro, and fennel, and it is the only species in its genus. Its native range stretches from North Africa (Morocco to Libya and south to Chad) through the Near and Middle East, Cyprus, Iran, and the Arabian Peninsula; it has naturalized across much of the world. The epithet graveolens means “strong-smelling.”

It is an upright, highly aromatic annual that usually reaches 18 in – 4 ft tall in cultivation. The hollow, branched stems are green with white stripes. The blue-green leaves, divided into thread-like segments, give the plant a feathery look reminiscent of fennel. A long taproot explains why dill resents being transplanted.

In hot or dry weather, the plant sends up a long flower stalk topped with flat umbels of tiny yellow flowers, 3–6 in across. The “seeds,” which are actually dry fruits, oval, flattened, and ribbed, about 0 in long, ripen a few weeks after bloom. Leaves, flowers, and seeds are all edible.

Common cultivars: ‘Bouquet’ (2–3 ft), productive for both leaves and seed; ‘Long Island Mammoth’, tall and popular for pickling; ‘Fernleaf’, compact (about 18 in) and slow to bolt, ideal for pots; ‘Dukat’, strongly flavored; ‘Ella’ and ‘Teddy’, dense types bred for containers.

Light

Dill needs full sun, ideally six to eight hours of direct sun a day: that is what produces sturdy stems and a good harvest. Too much shade gives stretched, floppy plants that topple over.

Indoors, it needs at least five to six hours of direct sun, at your brightest window. Outdoors, shelter it from strong gusts: the hollow stems snap in wind, pounding rain, or hail.

Watering

Instead of following a fixed schedule, feel the soil: it should stay evenly moist without being soggy; if it still sticks to your fingers, wait. Consistent watering helps delay bolting, because heat and dry spells trigger flowering. On the other hand, too much water makes plants leggy and encourages powdery mildew.

Once established in the ground, dill uses little water and tolerates drier soil, especially after it sets seed. In containers, check more often: the mix dries quickly in hot weather.

Potting mix

Dill grows in most soils, even poor ones, as long as they drain well; it prefers a sandy loam that is slightly acidic to neutral (pH 5.6 to 6.5). There is no need to enrich it: soil amended at sowing time is enough, or else one light application of fertilizer in late spring. Too much fertilizer encourages powdery mildew.

In containers, ordinary potting mix works well, in a deep pot that leaves room for the taproot.

Temperature

Dill is a cool-season annual that grows best between 61–70 °F. Sow it once nights stay above 45 °F; soil close to 70 °F speeds up emergence. Seedlings handle light frost, and an established plant survives down to about 25 °F, which makes late-summer sowings for a fall harvest possible. It is grown as an annual in USDA zones 2a to 11b.

Above 95 °F, seed production drops, and heat pushes the plant to flower at the expense of its foliage: in summer, choose a slow-bolting variety.

Repotting

Dill is not repotted: its taproot dislikes being disturbed, and plants started in cell packs establish poorly. Sow it directly in its final spot, in the ground or in a deep container, and stake tall varieties.

Pruning

Harvesting takes the place of pruning. Snip leaves as soon as the plant is a few inches tall, close to the stem, preferably early in the morning or late in the day. Regular cutting makes the plant bushier and delays flowering. Flavor peaks as the first flowers open; after that, the plant declines quickly.

Remove spent flowers unless you want plenty of volunteer seedlings. Fresh leaves keep about a week in the refrigerator; freezing preserves their flavor better than drying.

Propagation

Dill is propagated by seed only. Sow in spring, one to two weeks before the last hard frost or once nights stay above 45 °F. The seeds need light to germinate, so barely cover them, 0–0 in at most. Seedlings emerge in ten to fourteen days, sometimes up to three weeks in cool soil.

Three to four weeks after emergence, thin to 3–6 in apart for a leaf harvest; leave up to 12–15 in if you want full-sized plants for seed. Sow again every two to four weeks while the weather stays cool, and count on six to eight weeks before the first harvest.

Cut the umbels when the seeds are fully formed but before they turn brown, because they shatter when ripe. Let them dry for a week in a paper bag in a warm, dry spot; stored cool in an airtight jar, they still germinate several years later.

Common problems

• Early bolting: heat, drought, or overcrowded seedlings. Water consistently, thin, and pick a slow-bolting variety.
• Leggy plants that flop over: not enough sun, too much water, or wind exposure; stake tall varieties.
• Aphids: they show up mainly as the plant flowers and sets seed, curling and yellowing the leaves, and their honeydew leads to sooty mold. Knock them off with a strong spray of water or treat with insecticidal soap.
• Caterpillars: black swallowtail caterpillars, black with yellow-green markings and often in groups, can strip much of the foliage. Hand-pick them if there are too many, or let them grow into butterflies.
• Powdery mildew: a white powdery coating on the leaves, favored by humidity, shade, and overwatering.
• Damping-off and root rot: cold, waterlogged soil; sow in well-drained ground.
• Yellowing and leaf spots: yellow, reddish, or brown-spotted leaves and stunted plants; use clean seed, clear away plant debris, and do not sow carrot-family crops in the same spot the following year.

The same symptom can have several causes: always look at light, watering, temperature, and the roots before acting. Dill attracts hover flies, whose larvae eat aphids. Avoid sowing it next to carrots, whose yield it can reduce.

Toxicity

Dill is not toxic to dogs, cats, or horses, and it is a food plant for people: leaves, flowers, and seeds are all eaten. Its essential oils can, however, cause dermatitis in animals after prolonged contact.