Baltimore, Maryland: planting zone & frost dates
Baltimore is in USDA plant hardiness zone 7b, where the average coldest winter night reaches 5 to 10°F (-15.0 to -12.2°C). The typical last spring frost is around Mar 29 and the first fall frost around Nov 15.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Apr 4 | Nov 7 |
| Typical planning date (30% risk) | Mar 29 | Nov 15 |
| Median (50%) | Mar 24 | Nov 21 |
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 MD SCI CTR BALTIMORE, MD (USW00093784), 1.3 mi (2.1 km) from the city center and 20 ft lower than the city center (-6 m). Record used for the 1991–2020 normals: 19 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Baltimore
Baltimore spans more than one half-zone. Share of the city's land area by zone (via its 25 ZIP codes): 7b (62%), 8a (38%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
ZIP codes in Baltimore and their zones
| ZIP | Zone | Share of city land |
|---|---|---|
| 21224 | 8a | 8.4% |
| 21215 | 7b | 8.1% |
| 21230 | 8a | 7.8% |
| 21229 | 7b | 6.3% |
| 21206 | 7b | 6.2% |
| 21226 | 8a | 6.1% |
| 21218 | 7b | 5.3% |
| 21213 | 8a | 4.2% |
| 21216 | 7b | 4.1% |
| 21207 | 7b | 3.6% |
| 21210 | 7b | 3.6% |
| 21209 | 7b | 3.5% |
| 21211 | 7b | 3.5% |
| 21214 | 7b | 3.5% |
| 21212 | 7b | 3.2% |
| 21223 | 7b | 3.2% |
| 21225 | 8a | 2.8% |
| 21239 | 7b | 2.7% |
| 21217 | 7b | 2.6% |
| 21205 | 8a | 2.5% |
| 21202 | 8a | 2.0% |
| 21201 | 8a | 1.6% |
| 21234 | 7b | 1.2% |
| 21231 | 8a | 1.1% |
| 21233 | 8a | 0.0% |
Vegetable planting calendar for Baltimore
Dates are counted from the 30%-risk frost dates above (last frost Mar 29, first frost Nov 15). 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 1 – Feb 15 | Apr 5 – Apr 19 | — | — |
| Pepper | Jan 18 – Feb 1 | Apr 12 – Apr 26 | — | — |
| Lettuce | Feb 15 – Mar 1 | Mar 15 – Apr 5 | Mar 1 – Apr 12 | Sep 6 – Oct 4 |
| Green Beans | — | — | Apr 5 – May 10 | Aug 23 – Sep 6 |
| Sweet Corn | — | — | Apr 5 – May 3 | — |
| Zucchini & Summer Squash | Mar 1 – Mar 8 | Apr 5 – Apr 19 | Apr 5 – Apr 26 | Aug 23 – Sep 6 |
| Cucumber | Mar 1 – Mar 8 | Apr 12 – Apr 19 | Apr 5 – Apr 26 | Aug 23 – Sep 6 |
| Carrot | — | — | Mar 8 – Apr 12 | Aug 23 – Sep 6 |
| Onion | Jan 4 – Jan 18 | Mar 1 – Mar 15 | — | — |
| Potato | — | Mar 1 – Mar 22 | — | — |
| Basil | Feb 15 – Mar 1 | Apr 12 – Apr 26 | Apr 12 – May 3 | — |
| Spinach | — | — | Feb 15 – Mar 15 | Sep 20 – Oct 18 |
| Kale | Feb 1 – Feb 15 | Mar 1 – Mar 22 | Mar 1 – Mar 22 | Sep 6 – Oct 4 |
| Broccoli | Feb 1 – Feb 15 | Mar 15 – Apr 5 | — | Aug 23 – Sep 6 |
| Peas | — | — | Feb 15 – Mar 8 | Sep 6 – Sep 20 |
| Eggplant | Jan 18 – Feb 1 | Apr 12 – Apr 26 | — | — |
| Cabbage | Feb 1 – Feb 15 | Mar 1 – Mar 15 | — | Aug 23 – Sep 6 |
| Radish | — | — | Feb 22 – Apr 12 | Oct 4 – Nov 1 |
| Strawberry | — | Mar 1 – Mar 22 | — | — |
| Beets | — | — | Mar 8 – Apr 19 | Sep 6 – Sep 20 |
Nearby cities in Maryland
- Frederick — zone 7a, last frost Apr 7, first frost Nov 1
More: all Maryland cities · other zone 7b cities: New York, NY, Philadelphia, PA, Oklahoma City, OK, Nashville, TN, Washington, DC, Albuquerque, NM, Tulsa, OK, Newark, NJ
Baltimore gardening questions
When is the last frost in Baltimore, MD?
Plan around Mar 29. At NOAA's Md Science Center Baltimore, MD station, 1.3 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 Mar 24, and after Apr 4 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Mar 11. The last frost is fairly predictable here: only 27 days separate the 90% and 10% dates (median for cities on this site: 36 days).
When should I plant tomatoes in Baltimore, MD?
Start seeds indoors Feb 1 – Feb 15 and set transplants outside Apr 5 – Apr 19, once nights stay above 50°F and the soil is near 60°F. That leaves 231 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 Baltimore?
About 244 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 224 days, and in 1 year in 10 it runs 268 days or more. In fall there is a 10% chance of frost by Nov 7 and a 30% chance by Nov 15.
When should I plant a fall garden in Baltimore?
Count back from the first fall frost (Nov 15): transplant broccoli Aug 23 – Sep 6; sow kale Sep 6 – Oct 4; sow lettuce Sep 6 – Oct 4; sow radishes Oct 4 – Nov 1. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Dec 5. How the math works: succession and fall planting.
Did Baltimore's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Baltimore is zone 7b 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 Baltimore in zone 7b?
No. Zone 7b covers about 62% of the city's land; the rest is in 8a (38%), measured across the city's 25 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.