When to Plant Dill

Spring: around the last frost

Dill is a cool-season herb that handles light frost, so it can go in before many other crops. Illinois, UW-Madison and NC State all recommend sowing about a week or two before the last spring frost. The University of Maryland says to wait until all danger of frost has passed. The dates for your zone above span both approaches; choose the early end if your spring warms quickly and the later end if late hard freezes are common.

Sow seed where the plants will grow. Dill’s taproot makes it a poor transplant, and seed is quick: seedlings appear in about 10 to 14 days (UW-Madison, NC State), or 7 to 21 days depending on soil temperature (Utah State). Cold soil slows germination, which is one more reason not to rush far ahead of the frost date.

Keep sowing while it is cool

A single sowing gives a short window of good leaves. Dill flowers as the weather turns hot or dry, and Illinois notes that plants decline soon after they bolt. Utah State says leaves are ready about 6 to 8 weeks after sowing and taste best as flowers begin to open, so a steady supply depends on staggered sowings.

Sources differ on the interval: every 10 to 14 days (UW-Madison), every two weeks (Illinois), every 2 to 4 weeks (NC State) or every 4 to 6 weeks (Utah State). Shorter intervals give a more even supply of leaves.

Summer and fall

Late-spring and summer sowings bolt faster in heat. UC Cooperative Extension Sacramento notes that dill, like cilantro, goes to seed quickly in hot weather. If you want seed heads for pickling, a late-spring sowing left to flower serves that purpose; Illinois says seed matures about 2 to 3 weeks after the blossoms appear.

For leaves, resume sowing in late summer. UW-Madison says late-summer plantings give a fall harvest because dill tolerates light frost. It also notes that seed sown in late fall can sprout the following spring, and plants left to drop seed in fall will usually come back on their own.

Warm-winter areas

In zones 9 and 10, dill grows best through the cool months and fades in summer heat.

• Florida: UF/IFAS Gardening Solutions recommends sowing September through December, with spring also possible; the UF/IFAS Osceola County calendar for Central Florida marks October through December.
• Texas Gulf Coast: the Galveston County office of Texas A&M AgriLife names October as a good planting time.
• Low desert: University of Arizona Extension in Tucson gives two windows, October to November and February to April. The Yuma County calendar runs plantings from October through February, with harvest in February and March.

Dill is also the main food plant for black swallowtail caterpillars in many gardens, and UF/IFAS highlights its role as the butterfly’s host plant in Florida. Sowing a little more than you need, and sowing again a few weeks later, keeps leaves for the kitchen even when caterpillars find a planting.