Baltimore, MD 21287 planting calendar
- USDA zone
- 7b5 to 10 °F
- Last frost
- Mar 24avg, 32°F
- First frost
- Nov 21avg, 32°F
- Growing season
- 244days
Baltimore, Maryland is in USDA plant hardiness zone 7b. Its average last spring frost is around March 24 and the first fall frost around November 21, giving a growing season of about 244 days (NOAA 1991–2020 normals, 32°F, median). Start tender crops like tomatoes and peppers indoors weeks before the last frost and set them out afterward; sow hardy crops such as peas, spinach, and lettuce before it. The planner below turns those frost dates into a printable per-crop planting calendar.
Baltimore planting calendar
Each crop's windows are counted from Baltimore's average frost dates. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees.
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting |
|---|---|---|---|---|---|
| Tomato | Tender | Jan 27 – Feb 10 | Mar 31 – Apr 7 | May 30 – Jun 19 | — |
| Pepper | Very tender | Jan 13 – Jan 27 | Apr 7 – Apr 14 | Jun 6 – Jul 6 | — |
| Cucumber | Tender | Feb 24 – Mar 3 | Mar 31 – Apr 7 | May 20 – Jun 9 | — |
| Summer squash / zucchini | Tender | — | Mar 31 – Apr 7 | May 15 – May 30 | — |
| Bush bean | Tender | — | Mar 31 – Apr 7 | May 20 – May 30 | Sep 22 – Oct 2 |
| Sweet corn | Tender | — | Mar 24 – Apr 7 | May 23 – Jun 22 | — |
| Basil | Very tender | Feb 10 – Feb 24 | Mar 31 – Apr 7 | Apr 30 – May 15 | — |
| Lettuce | Half-hardy | Feb 10 – Feb 24 | Feb 24 – Mar 10 | Apr 10 – Apr 25 | Sep 8 – Sep 23 |
| Pea | Hardy | — | Feb 10 – Feb 24 | Apr 6 – Apr 21 | Aug 29 – Sep 13 |
| Spinach | Hardy | — | Feb 10 – Feb 24 | Mar 22 – Apr 1 | Sep 18 – Sep 28 |
| Carrot | Half-hardy | — | Mar 3 – Mar 10 | May 2 – May 22 | Aug 19 – Sep 8 |
| Broccoli | Half-hardy | Jan 27 – Feb 10 | Feb 24 – Mar 10 | Apr 20 – May 10 | Aug 24 – Sep 13 |
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Frost & freeze dates
From NOAA's 1991–2020 Climate Normals at station USW00093784. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 (p10 for spring, p90 for fall) — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | Apr 3 | Apr 15 | Nov 10 | Nov 24 | 221 |
| 32°F (freeze) | Mar 24 | Apr 4 | Nov 21 | Dec 8 | 244 |
| 28°F | Mar 11 | Mar 26 | Dec 5 | Dec 25 | 270 |
| 24°F | Mar 2 | Mar 16 | Dec 23 | Jan 12 | 294 |
32°F is the standard "freeze" line that damages tender crops; lighter 36°F frost can nip the most cold-sensitive plants, while hardy crops shrug off light frost down toward 28°F. Use the threshold that matches what you are protecting.
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. Warm-season crops need a long, warm GDD total; a short, cool GDD total favors greens and brassicas.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 4,686 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 7,431 | cool-season crops (brassicas, greens) |
Hardiness zone 7b
Baltimore sits in USDA plant hardiness zone 7b on the 2023 map — meaning its average annual extreme minimum winter temperature is about 5 to 10 °F. That number tells you which perennials, shrubs, and trees reliably survive an average winter here; it does not set your planting dates, which come from the frost calendar above.
Explore more places in zone 7b, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Baltimore?
- Baltimore, Maryland is in USDA plant hardiness zone 7b on the 2023 map (average annual extreme minimum temperature 5 to 10 °F) — from the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. See the methodology page for sources.
- When is the last frost in Baltimore?
- The average (median) last spring frost at 32°F is around March 24, from NOAA's 1991–2020 climate normals at the nearest reporting station. Roughly one year in ten the last frost is as late as April 4, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Baltimore?
- The average first fall frost at 32°F is around November 21. That leaves a growing season of about 244 days between the average last spring and first fall frosts.
- When should I start tomatoes in Baltimore?
- Start tomato seeds indoors about Jan 27 – Feb 10 and transplant them outside about Mar 31 – Apr 7, once the danger of frost has passed. Estimated first harvest is around May 30 – Jun 19.
- How long is the growing season in Baltimore?
- About 244 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~March 24) and the average first fall frost (~November 21). Cold-hardy crops extend usable time at both ends; frost-tender crops fit inside it.
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020 for station USW00093784 (Md Sci Ctr Baltimore, 2.7 km away). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.