Washington, DC planting calendar

When to plant rosemary in Washington, DC — sow, transplant & harvest dates

Washington, DC is mostly USDA zone 8a (range 7b-8a). Dates below are derived from rosemary's frost tolerance and Washington, DC's frost window — not generic national averages.

Rosemary planting timetable for Washington, DC

Stage	When in Washington, DC	Anchor
Start seeds indoors	early February (February 4)	10 weeks before the last frost (mid-April)
Transplant outside	late April (April 29)	14 days after the last frost (mid-April)
First harvest (estimate)	late July (July 28)	~90 days from transplant

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why Washington, DC's climate shifts the rosemary dates

Washington, DC's last spring frost averages mid-April and first fall frost late October, which sets the whole planting clock. Washington, DC sits in a warm mid-Atlantic pocket where the urban heat island pushes much of the city into zone 8a — warmer than the surrounding suburbs. Wait for warm soil — rosemary stall in cold ground even after the air warms, so don't rush them out.

Start seeds indoors 10–12 weeks before the last frost; germination is slow and erratic (14–21 days at 18–21 °C / 65–70 °F) with low viability, so propagation by stem cuttings is preferred by most Extension services. Transplant outdoors after the last frost once soil has warmed — rosemary is perennial only in USDA zones 7–10 (established plants survive to about −12 °C / 10 °F); in zones 6 and colder treat as a tender annual or overwinter potted plants indoors before the first autumn frost. Tip harvests of stem ends begin around 80–100 days from transplant.

Frost-risk note

Don't plant before mid-April — a hard freeze can still set young plants back. In outer neighborhoods away from the urban core (zone 7b) the safe date runs a week or two later.

Regional variation within Washington, DC

outer neighborhoods away from the urban core (zone 7b) runs roughly 1-2 weeks behind the state average; the dense urban core, lifted by the city heat-island (zone 8a) can plant 1-2 weeks earlier.

Downtown DC — USDA zone 8a
Georgetown — USDA zone 8a
Anacostia — USDA zone 7b

What else to plant in Washington, DC around then

Pair the post-frost slot with other warm-season crops — peppers, beans, squash, and cucumbers.

Quick-grow guide

Sun: Full sun — 6+ hours direct.
Soil temperature for germination: 18–21 °C (65–70 °F).
Spacing: 18–36 inches (45–90 cm) between plants.
Days to harvest: ~90 days from planting out.

Frequently asked questions

When is the best time to plant rosemary in Washington, DC?

In Washington, DC (mostly USDA zone 8a), sow rosemary indoors around early February, transplant outdoors late April (after the last frost, mid-April), and harvest from late July. Rosemary are half-hardy — young plants shrug off a light frost but not a hard freeze, so sowing can start a couple of weeks before the last spring frost.

What USDA zone is Washington, DC?

Most of Washington, DC sits in USDA hardiness zone 8a, with the state spanning roughly 7b-8a from outer neighborhoods away from the urban core (zone 7b) to the dense urban core, lifted by the city heat-island (zone 8a). The last spring frost averages mid-April and the first fall frost late October.

Can you grow rosemary in Washington, DC?

Yes. Washington, DC's dominant zone 8a supports rosemary — the key is timing. Rosemary are half-hardy — young plants shrug off a light frost but not a hard freeze, so sowing can start a couple of weeks before the last spring frost.

Does the planting date change across Washington, DC?

outer neighborhoods away from the urban core (zone 7b) runs roughly 1-2 weeks behind the state average; the dense urban core, lifted by the city heat-island (zone 8a) can plant 1-2 weeks earlier.

What else can I plant in Washington, DC around the same time?

Pair the post-frost slot with other warm-season crops — peppers, beans, squash, and cucumbers.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.