Coos Bay, OR planting zone & frost dates
Coos Bay is in USDA hardiness zone 9a. The last spring frost usually comes around February 21 and the first fall frost around December 9, for a growing season of about 294 days.
Planting calendar for Coos Bay
Dates are counted from the average last spring frost (February 21) 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: Dec 27 – Jan 10 Transplant outdoors: Feb 28 – Mar 7 |
| Peppers | Start seeds indoors: Dec 13 – Dec 27 Transplant outdoors: Mar 7 – Mar 14 |
| Eggplant | Start seeds indoors: Dec 13 – Dec 27 Transplant outdoors: Mar 7 – Mar 14 |
| Broccoli | Start seeds indoors: Dec 13 – Dec 27 Transplant outdoors: Jan 24 – Feb 7 |
| Cabbage | Start seeds indoors: Dec 13 – Dec 27 Transplant outdoors: Jan 24 – Feb 7 |
| Onions (sets) | Plant outdoors: Jan 24 – Feb 7 |
| Peas | Sow outdoors: Jan 10 – Jan 24 |
| Spinach | Sow outdoors: Jan 10 – Jan 24 |
| Lettuce | Sow outdoors: Jan 24 – Feb 7 |
| Carrots | Sow outdoors: Jan 24 – Feb 7 |
| Potatoes | Plant outdoors: Jan 24 – Feb 7 |
| Beans | Sow outdoors: Feb 28 – Mar 7 |
| Sweet corn | Sow outdoors: Feb 28 – Mar 7 |
| Cucumbers | Sow outdoors: Feb 28 – Mar 7 |
| Squash & zucchini | Sow outdoors: Feb 28 – Mar 7 |
| Basil | Start seeds indoors: Jan 10 – Jan 24 Transplant outdoors: Feb 28 – Mar 7 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Oct 14 (8 weeks before the average first fall frost on Dec 9).
Useful for zone 9a 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
- Shade cloth — for hot summers
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Dec 31 | Feb 21 | Mar 25 |
| First 32°F frost in fall is before | Jan 28 | Dec 9 | Nov 12 |
How to read it: in spring there is a 10% chance of a frost after March 25, so that is a safe date for tender plants. In fall there is a 10% chance of frost before November 12. A hard freeze (28°F) usually ends around January 4.
Hardiness zone by ZIP code in Coos Bay
- 97420 zone 9a
Nearby cities
- Roseburg zone 8b, last frost Mar 23
- Newport zone 9b, last frost Mar 21
- Grants Pass zone 8b, last frost Apr 8
- Agate Beach zone 9b, last frost Mar 12
- Eugene zone 8b, last frost Apr 11
- Springfield zone 8b, last frost Apr 11
- Corvallis zone 8b, last frost Apr 17
- Central Point zone 8b, last frost Apr 8
Questions
What growing zone is Coos Bay, OR?
Coos Bay is in USDA Plant Hardiness Zone 9a (average extreme winter low 20°F to 25°F), according to the USDA 2023 map.
When is the last frost in Coos Bay?
The average last spring frost (32°F) in Coos Bay is February 21. There is still a 10% chance of frost until March 25.
When can I plant tomatoes in Coos Bay?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Feb 28 – Mar 7. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station North Bend Rgnl Ap, OR (USW00024284), 5.6 km (3.5 mi) from the city center, elevation 5 m, based on 29 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.