Washington, DC planting calendar

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

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

Kohlrabi planting timetable for Washington, DC

Stage	When in Washington, DC	Anchor
Start seeds indoors	mid-March (March 11)	5 weeks before the last frost (mid-April)
Transplant outside	late March (March 25)	21 days before the last frost (mid-April)
First harvest (estimate)	mid-May (May 19)	~55 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 kohlrabi 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. Sow early — kohlrabi bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Kohlrabi is a fast-maturing brassica that tolerates light frost down to about -4 °C but turns woody and pithy when daytime temperatures exceed 27 °C; transplant or direct-sow 3–4 weeks before the last spring frost for a summer harvest, or time a second sowing so plants mature in the cool days of early autumn. Harvest promptly when the swollen stem reaches 5–7 cm (2–3 inches) in diameter — larger bulbs become fibrous. Succession-sow every 3 weeks to extend the harvest window.

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

The same early window suits peas, lettuce, spinach, and onion sets.

Quick-grow guide

Sun: Full sun — 6+ hours direct.
Soil temperature for germination: 7-29 °C (45-85 °F).
Spacing: 6-9 inches (15-23 cm) between plants.
Days to harvest: ~55 days from planting out.

Frequently asked questions

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

In Washington, DC (mostly USDA zone 8a), sow kohlrabi indoors around mid-March, transplant outdoors late March (before the last frost, mid-April), and harvest from mid-May. Kohlrabi 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 kohlrabi in Washington, DC?

Yes. Washington, DC's dominant zone 8a supports kohlrabi — the key is timing. Kohlrabi 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?

The same early window suits peas, lettuce, spinach, and onion sets.

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.