Brunswick, ME planting zone & frost dates
Brunswick is in USDA hardiness zone 5b. The last spring frost usually comes around May 2 and the first fall frost around October 10, for a growing season of about 160 days.
Planting calendar for Brunswick
Dates are counted from the average last spring frost (May 2) 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: Mar 7 – Mar 21 Transplant outdoors: May 9 – May 16 |
| Peppers | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: May 16 – May 23 |
| Eggplant | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: May 16 – May 23 |
| Broccoli | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: Apr 4 – Apr 18 |
| Cabbage | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: Apr 4 – Apr 18 |
| Onions (sets) | Plant outdoors: Apr 4 – Apr 18 |
| Peas | Sow outdoors: Mar 21 – Apr 4 |
| Spinach | Sow outdoors: Mar 21 – Apr 4 |
| Lettuce | Sow outdoors: Apr 4 – Apr 18 |
| Carrots | Sow outdoors: Apr 4 – Apr 18 |
| Potatoes | Plant outdoors: Apr 4 – Apr 18 |
| Beans | Sow outdoors: May 9 – May 16 |
| Sweet corn | Sow outdoors: May 9 – May 16 |
| Cucumbers | Sow outdoors: May 9 – May 16 |
| Squash & zucchini | Sow outdoors: May 9 – May 16 |
| Basil | Start seeds indoors: Mar 21 – Apr 4 Transplant outdoors: May 9 – May 16 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 15 (8 weeks before the average first fall frost on Oct 10).
Useful for zone 5b 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
- Cold frame / mini greenhouse — adds weeks to a short season
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Apr 24 | May 2 | May 14 |
| First 32°F frost in fall is before | Oct 27 | Oct 10 | Sep 29 |
How to read it: in spring there is a 10% chance of a frost after May 14, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 29. A hard freeze (28°F) usually ends around April 22.
Hardiness zone by ZIP code in Brunswick
- 04011 zone 5b
Nearby cities
- Lewiston zone 5b, last frost Apr 25
- Auburn zone 5b, last frost Apr 25
- South Portland zone 6a, last frost Apr 26
- Portland zone 6a, last frost Apr 26
- Augusta zone 5b, last frost Apr 27
- South Portland Gardens zone 6a, last frost Apr 26
- Westbrook zone 5b, last frost Apr 26
- West Scarborough zone 6a, last frost Apr 26
Questions
What growing zone is Brunswick, ME?
Brunswick is in USDA Plant Hardiness Zone 5b (average extreme winter low -15°F to -10°F), according to the USDA 2023 map.
When is the last frost in Brunswick?
The average last spring frost (32°F) in Brunswick is May 2. There is still a 10% chance of frost until May 14.
When can I plant tomatoes in Brunswick?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 9 – May 16. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Brunswick Nas, ME (USW00014611), 3.0 km (1.9 mi) from the city center, elevation 21 m, based on 14 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.