Augusta, ME planting zone & frost dates
Augusta is in USDA hardiness zone 5b. The last spring frost usually comes around April 27 and the first fall frost around October 16, for a growing season of about 172 days.
Planting calendar for Augusta
Dates are counted from the average last spring frost (April 27) 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 2 – Mar 16 Transplant outdoors: May 4 – May 11 |
| Peppers | Start seeds indoors: Feb 16 – Mar 2 Transplant outdoors: May 11 – May 18 |
| Eggplant | Start seeds indoors: Feb 16 – Mar 2 Transplant outdoors: May 11 – May 18 |
| Broccoli | Start seeds indoors: Feb 16 – Mar 2 Transplant outdoors: Mar 30 – Apr 13 |
| Cabbage | Start seeds indoors: Feb 16 – Mar 2 Transplant outdoors: Mar 30 – Apr 13 |
| Onions (sets) | Plant outdoors: Mar 30 – Apr 13 |
| Peas | Sow outdoors: Mar 16 – Mar 30 |
| Spinach | Sow outdoors: Mar 16 – Mar 30 |
| Lettuce | Sow outdoors: Mar 30 – Apr 13 |
| Carrots | Sow outdoors: Mar 30 – Apr 13 |
| Potatoes | Plant outdoors: Mar 30 – Apr 13 |
| Beans | Sow outdoors: May 4 – May 11 |
| Sweet corn | Sow outdoors: May 4 – May 11 |
| Cucumbers | Sow outdoors: May 4 – May 11 |
| Squash & zucchini | Sow outdoors: May 4 – May 11 |
| Basil | Start seeds indoors: Mar 16 – Mar 30 Transplant outdoors: May 4 – May 11 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 21 (8 weeks before the average first fall frost on Oct 16).
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 15 | Apr 27 | May 7 |
| First 32°F frost in fall is before | Oct 31 | Oct 16 | Oct 2 |
How to read it: in spring there is a 10% chance of a frost after May 7, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 2. A hard freeze (28°F) usually ends around April 15.
Hardiness zone by ZIP code in Augusta
- 04330 zone 5b
- 04332 zone 5b
- 04333 zone 5b
- 04336 zone 5b
- 04338 zone 5b
Nearby cities
- Waterville zone 5b, last frost May 2
- Brunswick zone 5b, last frost May 2
- Lewiston zone 5b, last frost Apr 25
- Auburn zone 5b, last frost Apr 25
- Portland zone 6a, last frost Apr 26
- South Portland zone 6a, last frost Apr 26
- South Portland Gardens zone 6a, last frost Apr 26
- Westbrook zone 5b, last frost Apr 26
Questions
What growing zone is Augusta, ME?
Augusta 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 Augusta?
The average last spring frost (32°F) in Augusta is April 27. There is still a 10% chance of frost until May 7.
When can I plant tomatoes in Augusta?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 4 – May 11. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Augusta State Ap, ME (USW00014605), 1.8 km (1.1 mi) from the city center, elevation 107 m, based on 27 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.