Boston, MA planting zone & frost dates
Boston is in USDA hardiness zone 7a. The last spring frost usually comes around April 4 and the first fall frost around November 9, for a growing season of about 218 days.
Planting calendar for Boston
Dates are counted from the average last spring frost (April 4) 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 7 – Feb 21 Transplant outdoors: Apr 11 – Apr 18 |
| Peppers | Start seeds indoors: Jan 24 – Feb 7 Transplant outdoors: Apr 18 – Apr 25 |
| Eggplant | Start seeds indoors: Jan 24 – Feb 7 Transplant outdoors: Apr 18 – Apr 25 |
| Broccoli | Start seeds indoors: Jan 24 – Feb 7 Transplant outdoors: Mar 7 – Mar 21 |
| Cabbage | Start seeds indoors: Jan 24 – Feb 7 Transplant outdoors: Mar 7 – Mar 21 |
| Onions (sets) | Plant outdoors: Mar 7 – Mar 21 |
| Peas | Sow outdoors: Feb 21 – Mar 7 |
| Spinach | Sow outdoors: Feb 21 – Mar 7 |
| Lettuce | Sow outdoors: Mar 7 – Mar 21 |
| Carrots | Sow outdoors: Mar 7 – Mar 21 |
| Potatoes | Plant outdoors: Mar 7 – Mar 21 |
| Beans | Sow outdoors: Apr 11 – Apr 18 |
| Sweet corn | Sow outdoors: Apr 11 – Apr 18 |
| Cucumbers | Sow outdoors: Apr 11 – Apr 18 |
| Squash & zucchini | Sow outdoors: Apr 11 – Apr 18 |
| Basil | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: Apr 11 – Apr 18 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Sep 14 (8 weeks before the average first fall frost on Nov 9).
Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Mar 25 | Apr 4 | Apr 17 |
| First 32°F frost in fall is before | Nov 22 | Nov 9 | Oct 29 |
How to read it: in spring there is a 10% chance of a frost after April 17, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 29. A hard freeze (28°F) usually ends around March 28.
Hardiness zone by ZIP code in Boston
- 02108 zone 7a
- 02109 zone 7a
- 02110 zone 7a
- 02111 zone 7a
- 02112 zone 7a
- 02113 zone 7a
- 02114 zone 7a
- 02115 zone 7a
- 02116 zone 7a
- 02117 zone 7a
- 02118 zone 7a
- 02123 zone 7a
- 02127 zone 7a
- 02128 zone 7a
- 02133 zone 7a
- 02163 zone 6b
- 02196 zone 7a
- 02201 zone 7a
- 02203 zone 7a
- 02204 zone 7a
- 02205 zone 7a
- 02206 zone 7a
- 02210 zone 7a
- 02211 zone 7a
- 02212 zone 7a
- 02215 zone 6b
- 02217 zone 7a
- 02222 zone 7a
- 02241 zone 7a
- 02283 zone 7a
- 02284 zone 7a
- 02293 zone 7a
- 02297 zone 7a
- 02298 zone 7a
Nearby cities
- Charlestown zone 7a, last frost Apr 4
- East Cambridge zone 7a, last frost Apr 4
- East Boston zone 7a, last frost Apr 4
- Back Bay zone 7a, last frost Apr 19
- Roxbury Crossing zone 7a, last frost Apr 19
- Chelsea zone 7a, last frost Apr 4
- Cambridge zone 6b, last frost Apr 4
- Somerville zone 7a, last frost Apr 4
Questions
What growing zone is Boston, MA?
Boston is in USDA Plant Hardiness Zone 7a (average extreme winter low 0°F to 5°F), according to the USDA 2023 map. Some ZIP codes of the city fall in zone 6b.
When is the last frost in Boston?
The average last spring frost (32°F) in Boston is April 4. There is still a 10% chance of frost until April 17.
When can I plant tomatoes in Boston?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 11 – Apr 18. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Boston Logan Intl Ap, MA (USW00014739), 4.0 km (2.5 mi) from the city center, elevation 4 m, based on 28 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.