Grass Valley, OR frost dates
Last spring frostMay 15median date
First fall frostOct 11median date
Growing season149 daysfrost-free
Hardiness zone7aZone 7a
How Grass Valley compares
- In 8 years out of 10, the last spring frost in Grass Valley falls between April 29 and June 6, a 38-day window. The first fall frost falls between September 27 and October 26.
- The median last frost is 29 days later than the Oregon median of Apr 16.
- Its 149-day growing season is longer than 24% of the 345 Oregon places with a regular frost season (state median 193 days).
- The last frost is 29 days later than the zone 7a median of Apr 16. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 7a chart.
- The weather station records an average of 134 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 29 |
| 50% (median) | May 15 |
| 10% (safe for tender plants) | June 6 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 27 |
| 50% (median) | October 11 |
| 90% (late) | October 26 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Grass Valley, OR
Grass Valley, OR frost dates — last frost May 15, first frost Oct 11, zone 7a. whenisthelastfrost.com
Crop
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Start indoors: Feb 20 to Mar 6Transplant outside: Apr 17 to May 1
Start indoors: Mar 6 to Mar 20Transplant outside: May 29 to Jun 12
Start indoors: Mar 6 to Mar 20Transplant outside: May 29 to Jun 12
Start indoors: Mar 20 to Apr 3Transplant outside: May 22 to Jun 5
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 24 to May 8Sow outdoors: Apr 17 to May 22Plant for fall: Aug 16 to Sep 13
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 17 to May 1Sow outdoors: Apr 17 to May 1Plant for fall: Aug 2 to Aug 23
Start indoors: Mar 20 to Apr 3Transplant outside: May 1 to May 15Plant for fall: Jul 5 to Jul 26
Start indoors: Mar 20 to Apr 3Transplant outside: Apr 24 to May 8Plant for fall: Jul 5 to Jul 26
Start indoors: Mar 20 to Apr 3Transplant outside: May 1 to May 15Plant for fall: Jul 5 to Jul 26
Start indoors: Apr 3 to Apr 17Transplant outside: Jun 5 to Jun 19Sow outdoors: Jun 5 to Jun 19
Start indoors: Apr 3 to Apr 17Transplant outside: May 22 to Jun 5
Sow outdoors: Apr 3 to Apr 24Plant for fall: Jul 19 to Aug 9
Sow outdoors: Apr 3 to Apr 24Plant for fall: Aug 16 to Sep 6
Sow outdoors: Apr 10 to May 22Plant for fall: Aug 30 to Sep 20
Start indoors: Apr 17 to Apr 24Transplant outside: May 29 to Jun 5Sow outdoors: May 22 to Jun 5Plant for fall: Jul 26 to Aug 9
Start indoors: Apr 17 to Apr 24Sow outdoors: May 22 to Jun 5Plant for fall: Aug 2 to Aug 16
Start indoors: Apr 17 to Apr 24Sow outdoors: May 22 to Jun 5
Start indoors: Apr 17 to Apr 24Transplant outside: May 29 to Jun 12
Sow outdoors: Apr 24 to May 22Plant for fall: Jul 19 to Aug 2
Sow outdoors: Apr 24 to May 22Plant for fall: Aug 2 to Aug 16
Sow outdoors: Apr 24 to May 15
Sow outdoors: May 1 to May 29Plant for fall: Aug 2 to Aug 16
Sow outdoors: May 1 to May 22Plant for fall: Aug 16 to Sep 6
Sow outdoors: May 22 to Jun 12Plant for fall: Jul 26 to Aug 9
Sow outdoors: May 22 to Jun 5
Transplant outside: May 29 to Jun 19
Plant for fall: Sep 27 to Nov 1
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Grass Valley, OR
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 20 – Mar 6 | Apr 17 – May 1 | — | — |
| Peppers | Mar 6 – Mar 20 | May 29 – Jun 12 | — | — |
| Eggplant | Mar 6 – Mar 20 | May 29 – Jun 12 | — | — |
| Tomatoes | Mar 20 – Apr 3 | May 22 – Jun 5 | — | — |
| Lettuce | Mar 20 – Apr 3 | Apr 24 – May 8 | Apr 17 – May 22 | Aug 16 – Sep 13 |
| Kale | Mar 20 – Apr 3 | Apr 17 – May 1 | Apr 17 – May 1 | Aug 2 – Aug 23 |
| Broccoli | Mar 20 – Apr 3 | May 1 – May 15 | — | Jul 5 – Jul 26 |
| Cabbage | Mar 20 – Apr 3 | Apr 24 – May 8 | — | Jul 5 – Jul 26 |
| Cauliflower | Mar 20 – Apr 3 | May 1 – May 15 | — | Jul 5 – Jul 26 |
| Okra | Apr 3 – Apr 17 | Jun 5 – Jun 19 | Jun 5 – Jun 19 | — |
| Basil | Apr 3 – Apr 17 | May 22 – Jun 5 | — | — |
| Peas | — | — | Apr 3 – Apr 24 | Jul 19 – Aug 9 |
| Spinach | — | — | Apr 3 – Apr 24 | Aug 16 – Sep 6 |
| Radishes | — | — | Apr 10 – May 22 | Aug 30 – Sep 20 |
| Cucumbers | Apr 17 – Apr 24 | May 29 – Jun 5 | May 22 – Jun 5 | Jul 26 – Aug 9 |
| Zucchini & Summer Squash | Apr 17 – Apr 24 | — | May 22 – Jun 5 | Aug 2 – Aug 16 |
| Winter Squash & Pumpkins | Apr 17 – Apr 24 | — | May 22 – Jun 5 | — |
| Melons & Watermelon | Apr 17 – Apr 24 | May 29 – Jun 12 | — | — |
| Carrots | — | — | Apr 24 – May 22 | Jul 19 – Aug 2 |
| Beets | — | — | Apr 24 – May 22 | Aug 2 – Aug 16 |
| Potatoes | — | — | Apr 24 – May 15 | — |
| Swiss Chard | — | — | May 1 – May 29 | Aug 2 – Aug 16 |
| Cilantro | — | — | May 1 – May 22 | Aug 16 – Sep 6 |
| Green Beans | — | — | May 22 – Jun 12 | Jul 26 – Aug 9 |
| Sweet Corn | — | — | May 22 – Jun 5 | — |
| Sweet Potatoes | — | May 29 – Jun 19 | — | — |
| Garlic | — | — | — | Sep 27 – Nov 1 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Kent, OR weather station, 12 km away (elevation 2,710 ft (826 m)).
Frost dates near Grass Valley
- Moro May 12 · Oct 4
- Kent May 15 · Oct 11
- Dufur May 12 · Oct 7
- Wasco May 12 · Oct 4
- Shaniko May 22 · Oct 3
- Tygh Valley May 12 · Oct 7
- Rufus May 19 · Sep 25
- Condon May 10 · Oct 7
- Mikkalo May 10 · Oct 7
- Maupin May 5 · Oct 7
Frequently asked questions
When is the last frost in Grass Valley, OR?
The median last spring frost in Grass Valley, OR is May 15. There is still about a 10% chance of frost after June 6, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Grass Valley, OR?
The median first fall frost is October 11, with about a 10% chance of frost before September 27.
How long is the growing season in Grass Valley, OR?
About 149 days between the median last spring frost and first fall frost.
What planting zone is Grass Valley, OR?
Grass Valley, OR is in USDA hardiness zone 7a.