When to plant Swiss chard in District of Columbia

In spring, Mar 1 – May 25 in Washington.

In fall, June 1 – Sept 15 in Washington.

USDA's earliest safe spring and latest safe fall planting dates, matched to each place's average frost dates.

Swiss chard planting dates by place in District of Columbia
PlaceSpringFall
WashingtonMar 1 – May 25June 1 – Sept 15

Planting dates: USDA Home and Garden Bulletin No. 9 (1967), tables 4 and 5. Frost dates: NOAA U.S. Climate Normals 1991–2020. “—” means the place's frost date is outside the table. The full USDA table for swiss chard.