Anchorage, AK planting zone & frost dates
Anchorage is in USDA hardiness zone 5a. The last spring frost usually comes around May 1 and the first fall frost around September 29, for a growing season of about 150 days.
Planting calendar for Anchorage
Dates are counted from the average last spring frost (May 1) 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 6 – Mar 20 Transplant outdoors: May 8 – May 15 |
| Peppers | Start seeds indoors: Feb 20 – Mar 6 Transplant outdoors: May 15 – May 22 |
| Eggplant | Start seeds indoors: Feb 20 – Mar 6 Transplant outdoors: May 15 – May 22 |
| Broccoli | Start seeds indoors: Feb 20 – Mar 6 Transplant outdoors: Apr 3 – Apr 17 |
| Cabbage | Start seeds indoors: Feb 20 – Mar 6 Transplant outdoors: Apr 3 – Apr 17 |
| Onions (sets) | Plant outdoors: Apr 3 – Apr 17 |
| Peas | Sow outdoors: Mar 20 – Apr 3 |
| Spinach | Sow outdoors: Mar 20 – Apr 3 |
| Lettuce | Sow outdoors: Apr 3 – Apr 17 |
| Carrots | Sow outdoors: Apr 3 – Apr 17 |
| Potatoes | Plant outdoors: Apr 3 – Apr 17 |
| Beans | Sow outdoors: May 8 – May 15 |
| Sweet corn | Sow outdoors: May 8 – May 15 |
| Cucumbers | Sow outdoors: May 8 – May 15 |
| Squash & zucchini | Sow outdoors: May 8 – May 15 |
| Basil | Start seeds indoors: Mar 20 – Apr 3 Transplant outdoors: May 8 – May 15 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 4 (8 weeks before the average first fall frost on Sep 29).
Useful for zone 5a 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 19 | May 1 | May 9 |
| First 32°F frost in fall is before | Oct 12 | Sep 29 | Sep 17 |
How to read it: in spring there is a 10% chance of a frost after May 9, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 17. A hard freeze (28°F) usually ends around April 19.
Hardiness zone by ZIP code in Anchorage
- 99501 zone 5a
- 99502 zone 5b
- 99503 zone 3a
- 99504 zone 5a
- 99507 zone 5a
- 99508 zone 5a
- 99509 zone 5a
- 99510 zone 5b
- 99511 zone 5a
- 99513 zone 5b
- 99514 zone 5a
- 99515 zone 5a
- 99516 zone 5b
- 99517 zone 5b
- 99518 zone 5a
- 99519 zone 2a
- 99520 zone 5b
- 99521 zone 5a
- 99522 zone 5a
- 99523 zone 5a
- 99524 zone 5a
- 99529 zone 5b
- 99530 zone 5b
- 99599 zone 5a
- 99695 zone 6b
Nearby cities
- Eagle River zone 5a, last frost May 9
- Knik-Fairview zone 5a, last frost May 18
- College zone 2b, last frost May 18
- Fairbanks zone 2b, last frost May 16
- Badger zone 2a, last frost May 22
- Juneau zone 7a, last frost Apr 20
Questions
What growing zone is Anchorage, AK?
Anchorage is in USDA Plant Hardiness Zone 5a (average extreme winter low -20°F to -15°F), according to the USDA 2023 map. Some ZIP codes of the city fall in zones 2a, 3a, 5b, 6b.
When is the last frost in Anchorage?
The average last spring frost (32°F) in Anchorage is May 1. There is still a 10% chance of frost until May 9.
When can I plant tomatoes in Anchorage?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 8 – May 15. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Anchorage Merrill Fld, AK (USW00026409), 2.4 km (1.5 mi) from the city center, elevation 42 m, based on 23 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.