Frost Dates & Planting Calendar for Grass Valley, CA
Plan your garden around Grass Valley, CA's typical frost-free growing season, using NOAA climate normals and a 42-crop planting calendar built for this location.
Last Spring Frost
April 10
Safe Apr 30
Typical Apr 10
Risky Mar 17
First Fall Frost
November 13
Safe Oct 26
Typical Nov 13
Risky Dec 1
Growing Season
215 days
Typical last frost to typical first frost.
USDA Hardiness Zone
Zone 9a
Subtropical to frost-free — heat, not cold, is the main limit on what you can grow.
Data: NOAA station GRASS VALLEY #2, CA US, 1.8 km away.
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days until the typical last spring frost
Monthly Temperatures
Avg. high
Avg. temp
Avg. low
Planting Calendar
| Crop | Start indoors | Direct sow | Transplant | Fall planting | Maturity | Notes |
|---|---|---|---|---|---|---|
| Tomato | Feb 13 – Feb 27 | — | Apr 17 – Apr 24 | — | 60–85 days | Start indoors 6-8 weeks before last frost; transplant out 1-2 weeks after last frost once soil has warmed. |
| Pepper | Jan 30 – Feb 13 | — | Apr 17 – May 1 | — | 60–90 days | Slow to germinate; start indoors 8-10 weeks before last frost. Transplant only once nights stay above 55F, 1-3 weeks after last frost. |
| Eggplant | Jan 30 – Feb 13 | — | Apr 24 – May 1 | — | 65–85 days | Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant. |
| Cucumber | Mar 13 – Mar 20 | Apr 17 – Apr 24 | Apr 17 – Apr 24 | — | 50–65 days | Can be started indoors 3-4 weeks before transplanting, or direct-sown 1-2 weeks after last frost once soil is warm. |
| Zucchini | Mar 20 – Mar 27 | Apr 17 – May 1 | Apr 17 – Apr 24 | — | 45–55 days | Fast-growing squash; direct sow 1-3 weeks after last frost, or start indoors 2-3 weeks early for a head start. |
| Winter Squash | Mar 13 – Mar 20 | Apr 17 – May 1 | Apr 17 – Apr 24 | — | 80–110 days | Long season; direct sow after soil warms, or start indoors 3-4 weeks before last frost in short-season climates. |
| Pumpkin | — | Apr 17 – May 1 | — | — | 90–120 days | Direct sow 1-3 weeks after last frost; back-time from your first fall frost so the 90-120 day maturity window lands before it. |
| Watermelon | Mar 13 – Mar 20 | — | Apr 24 – May 1 | — | 70–90 days | Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost. |
| Cantaloupe | Mar 13 – Mar 20 | — | Apr 24 – May 1 | — | 70–90 days | Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting. |
| Corn | — | Apr 10 – Apr 24 | — | — | 60–100 days | Direct sow at last frost to 2 weeks after, once soil reaches 60F; does not transplant well. Succession sow every 2 weeks. |
| Green Bean | — | Apr 10 – Apr 24 | — | — | 50–65 days | Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush. |
| Pea | — | Feb 27 – Mar 13 | — | — | 55–70 days | Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Lettuce | — | Mar 13 – Mar 27 | — | Sep 18 – Oct 2 | 45–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts. |
| Spinach | — | Feb 27 – Mar 13 | — | Sep 18 – Oct 2 | 40–50 days | Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Kale | — | Mar 13 – Mar 27 | — | Sep 4 – Sep 18 | 50–65 days | Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants. |
| Arugula | — | Mar 13 – Mar 27 | — | Oct 2 – Oct 9 | 30–40 days | Fast-growing, cold-tolerant green; direct sow 2-4 weeks before last frost, succession sow every 2-3 weeks. |
| Swiss Chard | — | Mar 20 – Apr 3 | — | — | 50–60 days | Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too. |
| Broccoli | Feb 20 – Mar 6 | — | Mar 20 – Mar 27 | Sep 11 – Sep 18 | 55–80 days | Start indoors 5-7 weeks before last frost; transplant out 2-3 weeks before last frost (hardens off to light frost). |
| Cauliflower | Feb 20 – Mar 6 | — | Mar 27 – Apr 3 | Sep 4 – Sep 11 | 55–85 days | Fussier than broccoli about temperature swings; start indoors 5-7 weeks before last frost, transplant 1-2 weeks before last frost. |
| Cabbage | Feb 20 – Mar 6 | — | Mar 13 – Mar 27 | Sep 4 – Sep 18 | 60–100 days | Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost. |
| Brussels Sprouts | Feb 20 – Mar 6 | — | Mar 20 – Apr 3 | — | 90–110 days | Long-season crop best timed to mature after a light fall frost for sweetest flavor; start indoors 5-7 weeks before last frost. |
| Carrot | — | Mar 13 – Mar 27 | — | Aug 21 – Sep 4 | 60–80 days | Direct sow only (does not transplant); sow 2-4 weeks before last frost, as soon as soil can be worked. |
| Beet | — | Mar 13 – Mar 27 | — | Sep 4 – Sep 18 | 50–65 days | Direct sow 2-4 weeks before last frost; tolerates light frost. |
| Radish | — | Mar 6 – Mar 20 | — | Oct 2 – Oct 16 | 22–30 days | Very fast and cold-hardy; direct sow 3-5 weeks before last frost, as soon as soil can be worked. |
| Turnip | — | Mar 13 – Mar 27 | — | Sep 4 – Sep 18 | 40–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. |
| Onion | Jan 30 – Feb 13 | — | Mar 13 – Mar 27 | — | 90–120 days | Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings. |
| Garlic | — | — | — | Oct 16 – Oct 30 | 240–270 days | Fall-planted crop only; not planted in spring in most climates. |
| Potato | — | Mar 13 – Mar 27 | — | — | 70–120 days | Plant seed potatoes 2-4 weeks before last frost, as soon as soil can be worked and is above 45F; light frost on emerging foliage is usually tolerated. |
| Sweet Potato | — | — | Apr 24 – May 8 | — | 90–120 days | Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive. |
| Asparagus | — | — | Mar 13 – Mar 27 | — | 730–1095 days | Perennial; plant crowns 2-4 weeks before last frost as soon as soil can be worked. Takes 2-3 years to full production. |
| Crop | Start indoors | Direct sow | Transplant | Fall planting | Maturity | Notes |
|---|---|---|---|---|---|---|
| Basil | Feb 27 – Mar 6 | — | Apr 17 – Apr 24 | — | 50–70 days | Very frost/cold sensitive; start indoors 5-6 weeks before last frost, transplant only after all danger of frost (1-2 weeks after) and nights stay warm. |
| Cilantro | — | Mar 20 – Apr 3 | — | Sep 18 – Oct 2 | 45–70 days | Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring. |
| Parsley | Feb 13 – Feb 27 | — | Mar 27 – Apr 3 | — | 70–90 days | Slow to germinate; start indoors 6-8 weeks before last frost, transplant 1-2 weeks before last frost (biennial, cold-tolerant). |
| Dill | — | Mar 20 – Apr 3 | — | — | 40–60 days | Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer. |
| Oregano | Feb 13 – Feb 27 | — | Apr 10 – Apr 17 | — | 80–90 days | Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date. |
| Thyme | Feb 13 – Feb 27 | — | Apr 10 – Apr 17 | — | 85–95 days | Perennial herb, slow from seed; start indoors 6-8 weeks before last frost, transplant around/after last frost. |
| Crop | Start indoors | Direct sow | Transplant | Fall planting | Maturity | Notes |
|---|---|---|---|---|---|---|
| Sunflower | — | Apr 17 – May 1 | — | — | 70–100 days | Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting. |
| Zinnia | Mar 13 – Mar 20 | Apr 17 – May 1 | Apr 17 – Apr 24 | — | 60–70 days | Frost-tender; direct sow 1-3 weeks after last frost, or start indoors 3-4 weeks early for earlier blooms. |
| Marigold | Feb 27 – Mar 13 | — | Apr 17 – Apr 24 | — | 45–60 days | Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed. |
| Cosmos | Mar 13 – Mar 20 | Apr 17 – May 1 | Apr 17 – Apr 24 | — | 60–90 days | Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early. |
| Nasturtium | — | Apr 17 – May 1 | — | — | 50–65 days | Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed. |
| Dahlia | — | — | Apr 17 – May 1 | — | 90–120 days | Plant tubers 1-3 weeks after last frost once soil is warm (60F+); very frost-sensitive. |
Date ranges are estimates based on university extension guidelines and this city's NOAA frost normals — not a guarantee. Scroll to see all columns on narrow screens.
Frequently Asked Questions
When is the last frost in Grass Valley, CA?
Based on 1991–2020 NOAA climate normals for the GRASS VALLEY #2, CA US station, the last spring frost in Grass Valley typically falls around April 10. A cautious gardener might wait until April 30 (only a 10% chance of a later frost), while March 17 marks an earlier, higher-risk planting date.
When is the first frost in Grass Valley, CA in fall?
The first fall frost in Grass Valley typically arrives around November 13. To stay safe, assume frost could start as early as October 26; in milder years it can hold off until December 1.
How long is the growing season in Grass Valley, CA?
Grass Valley's average frost-free growing season is about 215 days, running from the typical last spring frost (April 10) to the typical first fall frost (November 13).
What USDA hardiness zone is Grass Valley, CA in?
Grass Valley, CA is in USDA plant hardiness zone 9a, per the USDA's 2023 Plant Hardiness Zone Map. Subtropical to frost-free — heat, not cold, is the main limit on what you can grow.