Frederick, Maryland: planting zone & frost dates
Frederick is in USDA plant hardiness zone 7a, where the average coldest winter night reaches 0 to 5°F (-17.8 to -15.0°C). The typical last spring frost is around Apr 7 and the first fall frost around Nov 1.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Apr 15 | Oct 23 |
| Typical planning date (30% risk) | Apr 7 | Nov 1 |
| Median (50%) | Apr 2 | Nov 6 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station FREDERICK POLICE BRKS, MD (USC00183348), 1.8 mi (2.9 km) from the city center and 39 ft higher than the city center (+12 m). Record used for the 1991–2020 normals: 12 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Frederick
Frederick spans more than one half-zone. Share of the city's land area by zone (via its 5 ZIP codes): 7a (91%), 7b (9%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
Vegetable planting calendar for Frederick
Dates are counted from the 30%-risk frost dates above (last frost Apr 7, first frost Nov 1). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Feb 10 – Feb 24 | Apr 14 – Apr 28 | — | — |
| Pepper | Jan 27 – Feb 10 | Apr 21 – May 5 | — | — |
| Lettuce | Feb 24 – Mar 10 | Mar 24 – Apr 14 | Mar 10 – Apr 21 | Aug 23 – Sep 20 |
| Green Beans | — | — | Apr 14 – May 19 | Aug 9 – Aug 23 |
| Sweet Corn | — | — | Apr 14 – May 12 | — |
| Zucchini & Summer Squash | Mar 10 – Mar 17 | Apr 14 – Apr 28 | Apr 14 – May 5 | Aug 9 – Aug 23 |
| Cucumber | Mar 10 – Mar 17 | Apr 21 – Apr 28 | Apr 14 – May 5 | Aug 9 – Aug 23 |
| Carrot | — | — | Mar 17 – Apr 21 | Aug 9 – Aug 23 |
| Onion | Jan 13 – Jan 27 | Mar 10 – Mar 24 | — | — |
| Potato | — | Mar 10 – Mar 31 | — | — |
| Basil | Feb 24 – Mar 10 | Apr 21 – May 5 | Apr 21 – May 12 | — |
| Spinach | — | — | Feb 24 – Mar 24 | Sep 6 – Oct 4 |
| Kale | Feb 10 – Feb 24 | Mar 10 – Mar 31 | Mar 10 – Mar 31 | Aug 23 – Sep 20 |
| Broccoli | Feb 10 – Feb 24 | Mar 24 – Apr 14 | — | Aug 9 – Aug 23 |
| Peas | — | — | Feb 24 – Mar 17 | Aug 23 – Sep 6 |
| Eggplant | Jan 27 – Feb 10 | Apr 21 – May 5 | — | — |
| Cabbage | Feb 10 – Feb 24 | Mar 10 – Mar 24 | — | Aug 9 – Aug 23 |
| Radish | — | — | Mar 3 – Apr 21 | Sep 20 – Oct 18 |
| Strawberry | — | Mar 10 – Mar 31 | — | — |
| Beets | — | — | Mar 17 – Apr 28 | Aug 23 – Sep 6 |
Nearby cities in Maryland
- Baltimore — zone 7b, last frost Mar 29, first frost Nov 15
More: all Maryland cities · other zone 7a cities: Louisville, KY, Wichita, KS, Cleveland, OH, Lexington, KY, St. Louis, MO, Boise, ID, Amarillo, TX, Providence, RI
Frederick gardening questions
When is the last frost in Frederick, MD?
Plan around Apr 7. At NOAA's Frederick Police Brks, MD station, 1.8 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Apr 2, and after Apr 15 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Mar 21. The 90% and 10% dates are 29 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in Frederick, MD?
Start seeds indoors Feb 10 – Feb 24 and set transplants outside Apr 14 – Apr 28, once nights stay above 50°F and the soil is near 60°F. That leaves 208 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Frederick?
About 218 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 196 days, and in 1 year in 10 it runs 239 days or more. In fall there is a 10% chance of frost by Oct 23 and a 30% chance by Nov 1.
When should I plant a fall garden in Frederick?
Count back from the first fall frost (Nov 1): transplant broccoli Aug 9 – Aug 23; sow kale Aug 23 – Sep 20; sow lettuce Aug 23 – Sep 20; sow radishes Sep 20 – Oct 18. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Nov 21. How the math works: succession and fall planting.
Did Frederick's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Frederick is zone 7a on both the 2012 and the 2023 USDA maps (PRISM/OSU ZIP listings). About 42% of U.S. ZIP codes kept their half-zone in 2023. Why the 2023 map is warmer.
Is all of Frederick in zone 7a?
No. Zone 7a covers about 91% of the city's land; the rest is in 7b (9%), measured across the city's 5 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.