Altamont, OR planting zone & frost dates
Altamont is in USDA hardiness zone 6b. The last spring frost usually comes around June 9 and the first fall frost around September 18, for a growing season of about 99 days.
Planting calendar for Altamont
Dates are counted from the average last spring frost (June 9) 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: Apr 14 – Apr 28 Transplant outdoors: Jun 16 – Jun 23 |
| Peppers | Start seeds indoors: Mar 31 – Apr 14 Transplant outdoors: Jun 23 – Jun 30 |
| Eggplant | Start seeds indoors: Mar 31 – Apr 14 Transplant outdoors: Jun 23 – Jun 30 |
| Broccoli | Start seeds indoors: Mar 31 – Apr 14 Transplant outdoors: May 12 – May 26 |
| Cabbage | Start seeds indoors: Mar 31 – Apr 14 Transplant outdoors: May 12 – May 26 |
| Onions (sets) | Plant outdoors: May 12 – May 26 |
| Peas | Sow outdoors: Apr 28 – May 12 |
| Spinach | Sow outdoors: Apr 28 – May 12 |
| Lettuce | Sow outdoors: May 12 – May 26 |
| Carrots | Sow outdoors: May 12 – May 26 |
| Potatoes | Plant outdoors: May 12 – May 26 |
| Beans | Sow outdoors: Jun 16 – Jun 23 |
| Sweet corn | Sow outdoors: Jun 16 – Jun 23 |
| Cucumbers | Sow outdoors: Jun 16 – Jun 23 |
| Squash & zucchini | Sow outdoors: Jun 16 – Jun 23 |
| Basil | Start seeds indoors: Apr 28 – May 12 Transplant outdoors: Jun 16 – Jun 23 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Jul 24 (8 weeks before the average first fall frost on Sep 18).
Useful for zone 6b 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 | May 22 | Jun 9 | Jun 26 |
| First 32°F frost in fall is before | Oct 1 | Sep 18 | Sep 4 |
How to read it: in spring there is a 10% chance of a frost after June 26, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 4. A hard freeze (28°F) usually ends around May 21.
Nearby cities
- Klamath Falls zone 6b, last frost Jun 9
- Ashland zone 8a, last frost May 6
- Medford zone 8b, last frost Apr 8
- Central Point zone 8b, last frost Apr 8
- Grants Pass zone 8b, last frost Apr 8
- Roseburg zone 8b, last frost Mar 23
- Bend zone 6b, last frost Jun 6
- Redmond zone 6b, last frost Jun 9
Questions
What growing zone is Altamont, OR?
Altamont is in USDA Plant Hardiness Zone 6b (average extreme winter low -5°F to 0°F), according to the USDA 2023 map.
When is the last frost in Altamont?
The average last spring frost (32°F) in Altamont is June 9. There is still a 10% chance of frost until June 26.
When can I plant tomatoes in Altamont?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Jun 16 – Jun 23. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Klamath Falls Intl Ap, OR (USW00094236), 6.7 km (4.2 mi) from the city center, elevation 1245 m, based on 21 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.