Healdsburg, CA planting zone & frost dates
Healdsburg is in USDA hardiness zone 9b. The last spring frost usually comes around February 15 and the first fall frost around December 2, for a growing season of about 292 days.
Planting calendar for Healdsburg
Dates are counted from the average last spring frost (February 15) 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 21 – Jan 4 Transplant outdoors: Feb 22 – Mar 1 |
| Peppers | Start seeds indoors: Dec 7 – Dec 21 Transplant outdoors: Mar 1 – Mar 8 |
| Eggplant | Start seeds indoors: Dec 7 – Dec 21 Transplant outdoors: Mar 1 – Mar 8 |
| Broccoli | Start seeds indoors: Dec 7 – Dec 21 Transplant outdoors: Jan 18 – Feb 1 |
| Cabbage | Start seeds indoors: Dec 7 – Dec 21 Transplant outdoors: Jan 18 – Feb 1 |
| Onions (sets) | Plant outdoors: Jan 18 – Feb 1 |
| Peas | Sow outdoors: Jan 4 – Jan 18 |
| Spinach | Sow outdoors: Jan 4 – Jan 18 |
| Lettuce | Sow outdoors: Jan 18 – Feb 1 |
| Carrots | Sow outdoors: Jan 18 – Feb 1 |
| Potatoes | Plant outdoors: Jan 18 – Feb 1 |
| Beans | Sow outdoors: Feb 22 – Mar 1 |
| Sweet corn | Sow outdoors: Feb 22 – Mar 1 |
| Cucumbers | Sow outdoors: Feb 22 – Mar 1 |
| Squash & zucchini | Sow outdoors: Feb 22 – Mar 1 |
| Basil | Start seeds indoors: Jan 4 – Jan 18 Transplant outdoors: Feb 22 – Mar 1 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Oct 7 (8 weeks before the average first fall frost on Dec 2).
Useful for zone 9b 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
As an Amazon Associate, FrostZoneMap earns from qualifying purchases, at no extra cost to you.
Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Jan 4 | Feb 15 | Mar 17 |
| First 32°F frost in fall is before | Jan 1 | Dec 2 | Nov 14 |
How to read it: in spring there is a 10% chance of a frost after March 17, so that is a safe date for tender plants. In fall there is a 10% chance of frost before November 14. A hard freeze (28°F) usually ends around January 7.
Hardiness zone by ZIP code in Healdsburg
- 95448 zone 9b
Nearby cities
- Windsor zone 9a, last frost Mar 2
- Santa Rosa zone 9b, last frost Feb 25
- Rohnert Park zone 9a, last frost Feb 28
- Clearlake zone 9a, last frost Apr 10
- Petaluma zone 9a, last frost Feb 28
- Agua Caliente zone 9b, last frost Mar 2
- Sonoma zone 9b, last frost Mar 2
- Novato zone 9b, last frost Jan 11
Questions
What growing zone is Healdsburg, CA?
Healdsburg is in USDA Plant Hardiness Zone 9b (average extreme winter low 25°F to 30°F), according to the USDA 2023 map.
When is the last frost in Healdsburg?
The average last spring frost (32°F) in Healdsburg is February 15. There is still a 10% chance of frost until March 17.
When can I plant tomatoes in Healdsburg?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Feb 22 – Mar 1. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Healdsburg, CA (USC00043875), 2.1 km (1.3 mi) from the city center, elevation 54 m, based on 22 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.