District of Columbia vegetable planting calendar 2027: frost dates and when to plant
In the District of Columbia, the average last spring frost is March 29 in Washington (NOAA 1991-2020 normals). Below are planting dates for Washington for 27 common vegetables and herbs, worked out the way the Rowtime app does it: NOAA's average frost dates for the nearest weather station, with the planting rules of state extension guides. Dates are for the 2027 season.
Rowtime: Garden Planner works these dates out for your own ZIP code in District of Columbia, shows where each one comes from, and recalculates when a planting slips. Get Rowtime on the App Store.
Dates are estimates. Check your local extension office before you plant, and use your own frost records if you have them. Dates shift by a week or more within a state, so pick the city closest to your conditions.
Washington
When to plant tomatoes in Washington?
In Washington, DC, the average last spring frost is March 29 and the average first fall frost is November 8 (NOAA 1991-2020 normals, NATL ARBORETUM DC station, 4.1 km from ZIP 20001). For tomatoes, start seeds indoors March 3 to May 9 and plant out seedlings April 11 to August 10, following University of Maryland Extension (Home & Garden Information Center) and Purdue University Extension. Dates are for the 2027 season; sources last checked October 24, 2026.
Frost dates for Washington (20001)
- Last spring frost: Mar 29 on average, Apr 11 for a 10% risk of a later frost.
- First fall frost: Nov 8 on average, Oct 26 for a 10% risk of an earlier frost.
- USDA hardiness zone 8a (PRISM 2023 listing).
| Crop | When |
|---|---|
| Beet | Sow outdoors: Mar 14 to Mar 28 Sow outdoors for fall: Aug 31 to Sep 28 |
| Broccoli | Start seeds indoors: Feb 10 to Mar 19 Plant out seedlings: Feb 28 to Mar 14 Plant out seedlings for fall: Aug 31 to Sep 28 |
| Cabbage | Start seeds indoors: Feb 3 to Mar 2 Plant out seedlings: Feb 28 to Mar 14 Plant out seedlings for fall: Aug 31 to Sep 28 |
| Carrot | Sow outdoors: Mar 14 to Mar 28 |
| Cauliflower | Start seeds indoors: Feb 17 to Mar 19 Plant out seedlings: Mar 14 to Mar 28 Plant out seedlings for fall: Jul 9 to Aug 8 |
| Cucumber | Sow outdoors: Apr 25 to Aug 30 |
| Eggplant | Start seeds indoors: Mar 20 to Apr 18 Plant out seedlings: Apr 25 to Aug 10 |
| Green onion | Plant onion sets: Feb 28 to Mar 14 Plant out seedlings for fall: Aug 31 to Sep 28 |
| Kale | Sow outdoors: Feb 28 to Mar 14 Sow outdoors for fall: Aug 31 to Sep 28 |
| Lettuce | Sow outdoors: Mar 14 to Mar 28 Sow outdoors for fall: Aug 31 to Sep 28 |
| Melon and watermelon | Sow outdoors: Apr 25 to Jul 31 |
| Okra | Plant out seedlings: Apr 25 to Sep 4 |
| Onion | Plant onion sets: Feb 28 to Mar 14 |
| Pea | Sow outdoors: Feb 28 to Mar 14 |
| Pepper | Start seeds indoors: Mar 3 to Apr 2 Plant out seedlings: Apr 25 to Aug 10 |
| Potato | Plant seed potatoes: Feb 28 to Mar 14 |
| Snap bean | Sow outdoors: Apr 11 to Sep 9 |
| Spinach | Sow outdoors: Feb 28 to Mar 14 Sow outdoors for fall: Aug 31 to Sep 28 |
| Summer squash | Sow outdoors: Apr 25 to Sep 9 |
| Sweet corn | Sow outdoors: Apr 11 to Aug 10 |
| Sweet potato | Sprout slips indoors: Apr 3 to May 2 Plant out slips: Apr 25 to Jul 1 |
| Tomato | Start seeds indoors: Mar 3 to May 9 Plant out seedlings: Apr 11 to Aug 10 |
| Winter squash and pumpkin | Sow outdoors: Apr 25 to Jul 31 |
| Basil | Plant outdoors: May 2 to Aug 1 |
| Cilantro | Sow outdoors: Feb 2 to Apr 1 Sow outdoors for fall: Sep 16 to Sep 30 |
| Dill | Sow outdoors: Mar 17 to Apr 1 Sow outdoors for fall: Aug 1 to Sep 15 |
| Parsley | Sow outdoors: Mar 20 to Apr 18 Plant outdoors for fall: Aug 1 to Sep 30 |
Sources
Planting rules, in the order Rowtime tries them here:
- Purdue University Extension, Indiana Vegetable Planting Calendar (HO-186-W). Checked October 20, 2026.
- University of Maryland Extension (Home & Garden Information Center), Vegetable Planting Calendar for Central Maryland. Checked October 24, 2026.
- NC State Extension, Central North Carolina Planting Calendar for Annual Vegetables, Fruits, and Herbs (AG-756-01). Checked October 21, 2026.
Frost dates, locations and zones:
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991-2020 annual/seasonal (freeze probabilities).
- U.S. Census Bureau, 2025 Gazetteer Files: ZIP Code Tabulation Areas.
- PRISM Group, Oregon State University / USDA ARS, 2023 USDA Plant Hardiness Zone Map ZIP code listings. PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed 20 Oct 2026.
How the dates are worked out: a guide's rule such as "two weeks after the last frost" is applied to the station's NOAA date. Purdue's dates are 10% dates, so they are counted from the station's 10% date. When a guide gives no last date, the window closes early enough for the crop's longest days to harvest before the first fall frost. When a guide gives no first date for a fall planting, no fall window is shown. "Season too short" means the guide's window would close before it opens at this station's frost dates.
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