GreenlyWhen to plant cucumber in Washington, D.C.
In Washington, D.C., cucumber: sow seedlings around 2 March for the greenhouse and around 23 March for open ground; plant into a greenhouse around 13 April; plant out into open ground around 4 May.
Last spring frost around 31 March, first autumn frost around 16 November. Frost-free days: 230 days.
The dates follow the Greenly calendar: open ground a week after the last frost once the soil is warm enough for the crop, frost-hardy crops three weeks before it, an unheated greenhouse three weeks earlier, seedlings sown so they are ready on the day. In a cold year allow a week or two more.