by Stephanie Wrightson, Sonoma County Master Gardener
Anethum graveolens (Dill) is not just one of my favorite herbs – dill was named 2010 herb of the year by the International Herb Association. It is a graceful plant in the garden whose flowers attract beneficial insects, and both the leaves (“dill weed”) and seeds have culinary uses. Dill lends a wonderful flavor to many foods – not just fish and pickles! Dill is one of the few herbs that, while not difficult to grow, is a bit more challenging to sustain, as it requires flower removal and repeated sowing.
Dill seeds can be sown directly into the ground two to three weeks before the last usual frost date (which in Sonoma County is April 15). However, many County gardeners sow in early May to avoid any weather surprises. Sow dill every two to three weeks until early summer for a continuous crop of leaves throughout the growing season. Dill is heat-sensitive and will bolt when summer temperatures soar, but it can be sown again in September. Starting plants indoors is not recommended; dill, like other plants with taproots, does not transplant well. This is why a beautiful nursery dill plant seems to burst into flower as soon as it is planted out.
Harvest to Table, the website of Sonoma County Master Gardener and author Steve Albert, recommends three dill varieties: ‘Bouquet,’ a popular variety that grows to about 3 feet; ‘Fernleaf,’ a slow-to-bolt dwarf variety that grows to about 18-24 inches and is suited for container growing; and ‘Superdukat,’ a 2-foot hybrid which is intensely flavored and slow-bolting. ‘Long Island Mammoth,’ popular commercially, grows to about 30 inches and is a source of both leaves and seed. ‘Hercules’ and ‘Tetra Leaf’ are two more recent varieties that are slow to flower and, thus, have good leaf production.
Like most herbs, dill likes well-drained soil. If you have heavy clay, adequately amend the soil with composted organic material or build a bed for planting. Or, grow dill in an outdoor pot at least 12 inches deep so its taproot can be accommodated. While dill can be planted in rows, consider planting dill in a “clump” where it can be allowed to self-seed for successive crops. Dill thrives in full sun. If it does not receive enough light, it will get leggy. Since most varieties are bushy and tall, place dill along the sunny north side of your garden so that it doesn’t shade shorter sun-loving herbs or vegetables.
Directly sow seeds 1/4-inch deep; they need light to germinate. Plant in rows about two feet apart or prepare a square foot or larger area, broadcast the seeds, and rake the seeds into the soil at the recommended depth. Provide regular water until the plants are established and, thereafter, allow the soil to dry between irrigation; do not overwater. Thin seedlings when they are 2 to 4 inches tall, leaving the strongest plants. While Sunset Western Gardening recommends thinning to 18 inches, some gardeners thin conservatively so that the tall plants support each other in the wind. However, do not allow the plants to crowd each other; good air circulation around the base promotes healthy plants. Taller varieties may require staking. Dill can be used as soon as the needle-like foliage appears. Remove flowers to encourage growth (unless you are harvesting seed). If dill is allowed to flower, leaf production ceases; when it sets seed, the plant dies. Dill is heat-sensitive and bolts quickly; so, it is inevitable that it will not have a long life. Happily, new seeds germinate quickly and dill has two growing seasons in Sonoma County.