Greater Upper Marlboro, MD planting zone & frost dates
Greater Upper Marlboro is in USDA hardiness zone 7b. The last spring frost usually comes around April 9 and the first fall frost around October 29, for a growing season of about 203 days.
Planting calendar for Greater Upper Marlboro
Dates are counted from the average last spring frost (April 9) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Feb 12 – Feb 26 Transplant outdoors: Apr 16 – Apr 23 |
| Peppers | Start seeds indoors: Jan 29 – Feb 12 Transplant outdoors: Apr 23 – Apr 30 |
| Eggplant | Start seeds indoors: Jan 29 – Feb 12 Transplant outdoors: Apr 23 – Apr 30 |
| Broccoli | Start seeds indoors: Jan 29 – Feb 12 Transplant outdoors: Mar 12 – Mar 26 |
| Cabbage | Start seeds indoors: Jan 29 – Feb 12 Transplant outdoors: Mar 12 – Mar 26 |
| Onions (sets) | Plant outdoors: Mar 12 – Mar 26 |
| Peas | Sow outdoors: Feb 26 – Mar 12 |
| Spinach | Sow outdoors: Feb 26 – Mar 12 |
| Lettuce | Sow outdoors: Mar 12 – Mar 26 |
| Carrots | Sow outdoors: Mar 12 – Mar 26 |
| Potatoes | Plant outdoors: Mar 12 – Mar 26 |
| Beans | Sow outdoors: Apr 16 – Apr 23 |
| Sweet corn | Sow outdoors: Apr 16 – Apr 23 |
| Cucumbers | Sow outdoors: Apr 16 – Apr 23 |
| Squash & zucchini | Sow outdoors: Apr 16 – Apr 23 |
| Basil | Start seeds indoors: Feb 26 – Mar 12 Transplant outdoors: Apr 16 – Apr 23 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Sep 3 (8 weeks before the average first fall frost on Oct 29).
Useful for zone 7b gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Mar 27 | Apr 9 | Apr 24 |
| First 32°F frost in fall is before | Nov 11 | Oct 29 | Oct 14 |
How to read it: in spring there is a 10% chance of a frost after April 24, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 14. A hard freeze (28°F) usually ends around March 30.
Nearby cities
- Kettering zone 7b, last frost Apr 9
- Rosaryville zone 7b, last frost Apr 9
- Largo zone 7b, last frost Apr 9
- Mitchellville zone 7b, last frost Apr 22
- Bowie zone 7b, last frost Apr 22
- Forestville zone 7b, last frost Apr 9
- Summerfield zone 7b, last frost Mar 29
- Walker Mill zone 7b, last frost Mar 29
Questions
What growing zone is Greater Upper Marlboro, MD?
Greater Upper Marlboro is in USDA Plant Hardiness Zone 7b (average extreme winter low 5°F to 10°F), according to the USDA 2023 map.
When is the last frost in Greater Upper Marlboro?
The average last spring frost (32°F) in Greater Upper Marlboro is April 9. There is still a 10% chance of frost until April 24.
When can I plant tomatoes in Greater Upper Marlboro?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 16 – Apr 23. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Upper Marlboro 3 Nnw, MD (USC00189070), 2.9 km (1.8 mi) from the city center, elevation 40 m, based on 19 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.