Seed Starting Calendar for Maryland

Count back from the median last frost where you garden. At Frederick (Frederick Police Brks) that date is April 2, so for spring 2027 onions start indoors Dec 25 to Jan 8, peppers Feb 5 to Feb 19 and tomatoes Feb 12 to Feb 26. Across Maryland's 43 NOAA stations the median last frost runs from Mar 24 to Apr 29 for the middle 90 percent, so a garden near Sines Deep Creek starts later than one near Solomons.

It depends on the station. The earliest median last spring freeze in Maryland is March 22 at Solomons; the latest is May 9 at Sines Deep Creek. A median is a coin flip: at Frederick the last 32°F freeze comes after April 2 in half of years, and has passed by April 15 in 9 of 10 years (NOAA 1991 to 2020 normals).

UNH Extension sets tomatoes out 1 to 2 weeks after the last frost, which at Frederick is Apr 9 to Apr 16 in 2027. Tomatoes are frost tender, so the date to watch is April 15, when 9 of 10 springs at Frederick have had their last 32°F night. Hardening off starts two weeks before setting out (Mar 26 to Apr 9).

University of Maryland Extension (Home and Garden Information Center) publishes planting months by region (Central Maryland). For Central Maryland, tomatoes go in during May, June and July. Seeds for transplants go in 4 to 10 weeks ahead of those months, depending on the crop.

University of Maryland Extension (Home and Garden Information Center)'s When to Plant Vegetables (Vegetable Planting Calendar for Central Maryland) puts it this way: "The vegetable planting calendar was created for central Maryland, based on a last frost date of April 15 and a first frost date of October 25." The guide is linked below with the date it was read (September 21, 2026).

UNH Extension gives 8 to 10 weeks from seed to transplant for both, and sets peppers out 2 weeks after the last frost and eggplant 2 to 3 weeks after, so the sowing date is 6 to 8 weeks before the median last frost. At Frederick that is Feb 5 to Feb 19 for peppers.

About two weeks. University of Missouri Extension: "Hardening should be started about two weeks before planting in the garden." University of Minnesota Extension adds that seedlings should go out on a cloudy day or in the late afternoon.

Baltimore reaches its median last frost around Mar 24, Frederick around Apr 2, Salisbury on the Eastern Shore around Apr 10, and Oakland in Garrett County around May 6. Each station carries its own dates: Baltimore Mar 24 and Oakland May 6 at the median.