Frost Dates & Planting Calendar for Rancho Penasquitos, CA
Plan your garden around Rancho Penasquitos, CA's typical frost-free growing season, using NOAA climate normals and a 42-crop planting calendar built for this location.
Last Spring Frost
January 5
Safe Feb 1
Typical Jan 5
Risky Dec 13
First Fall Frost
January 2
Safe Dec 13
Typical Jan 2
Risky Jan 31
Growing Season
365 days
Typical last frost to typical first frost.
USDA Hardiness Zone
Zone 10a
Subtropical to frost-free — heat, not cold, is the main limit on what you can grow.
Data: NOAA station RANCHO BERNARDO, CA US, 7.6 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 | Nov 10 – Nov 24 | — | Jan 12 – Jan 19 | — | 60–85 days | Start indoors 6-8 weeks before last frost; transplant out 1-2 weeks after last frost once soil has warmed. |
| Pepper | Oct 27 – Nov 10 | — | Jan 12 – Jan 26 | — | 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 | Oct 27 – Nov 10 | — | Jan 19 – Jan 26 | — | 65–85 days | Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant. |
| Cucumber | Dec 8 – Dec 15 | Jan 12 – Jan 19 | Jan 12 – Jan 19 | — | 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 | Dec 15 – Dec 22 | Jan 12 – Jan 26 | Jan 12 – Jan 19 | — | 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 | Dec 8 – Dec 15 | Jan 12 – Jan 26 | Jan 12 – Jan 19 | — | 80–110 days | Long season; direct sow after soil warms, or start indoors 3-4 weeks before last frost in short-season climates. |
| Pumpkin | — | Jan 12 – Jan 26 | — | — | 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 | Dec 8 – Dec 15 | — | Jan 19 – Jan 26 | — | 70–90 days | Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost. |
| Cantaloupe | Dec 8 – Dec 15 | — | Jan 19 – Jan 26 | — | 70–90 days | Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting. |
| Corn | — | Jan 5 – Jan 19 | — | — | 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 | — | Jan 5 – Jan 19 | — | — | 50–65 days | Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush. |
| Pea | — | Nov 24 – Dec 8 | — | — | 55–70 days | Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Lettuce | — | Dec 8 – Dec 22 | — | Nov 7 – Nov 21 | 45–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts. |
| Spinach | — | Nov 24 – Dec 8 | — | Nov 7 – Nov 21 | 40–50 days | Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Kale | — | Dec 8 – Dec 22 | — | Oct 24 – Nov 7 | 50–65 days | Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants. |
| Arugula | — | Dec 8 – Dec 22 | — | Nov 21 – Nov 28 | 30–40 days | Fast-growing, cold-tolerant green; direct sow 2-4 weeks before last frost, succession sow every 2-3 weeks. |
| Swiss Chard | — | Dec 15 – Dec 29 | — | — | 50–60 days | Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too. |
| Broccoli | Nov 17 – Dec 1 | — | Dec 15 – Dec 22 | Oct 31 – Nov 7 | 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 | Nov 17 – Dec 1 | — | Dec 22 – Dec 29 | Oct 24 – Oct 31 | 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 | Nov 17 – Dec 1 | — | Dec 8 – Dec 22 | Oct 24 – Nov 7 | 60–100 days | Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost. |
| Brussels Sprouts | Nov 17 – Dec 1 | — | Dec 15 – Dec 29 | — | 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 | — | Dec 8 – Dec 22 | — | Oct 10 – Oct 24 | 60–80 days | Direct sow only (does not transplant); sow 2-4 weeks before last frost, as soon as soil can be worked. |
| Beet | — | Dec 8 – Dec 22 | — | Oct 24 – Nov 7 | 50–65 days | Direct sow 2-4 weeks before last frost; tolerates light frost. |
| Radish | — | Dec 1 – Dec 15 | — | Nov 21 – Dec 5 | 22–30 days | Very fast and cold-hardy; direct sow 3-5 weeks before last frost, as soon as soil can be worked. |
| Turnip | — | Dec 8 – Dec 22 | — | Oct 24 – Nov 7 | 40–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. |
| Onion | Oct 27 – Nov 10 | — | Dec 8 – Dec 22 | — | 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 | — | — | — | Dec 5 – Dec 19 | 240–270 days | Fall-planted crop only; not planted in spring in most climates. |
| Potato | — | Dec 8 – Dec 22 | — | — | 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 | — | — | Jan 19 – Feb 2 | — | 90–120 days | Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive. |
| Asparagus | — | — | Dec 8 – Dec 22 | — | 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 | Nov 24 – Dec 1 | — | Jan 12 – Jan 19 | — | 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 | — | Dec 15 – Dec 29 | — | Nov 7 – Nov 21 | 45–70 days | Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring. |
| Parsley | Nov 10 – Nov 24 | — | Dec 22 – Dec 29 | — | 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 | — | Dec 15 – Dec 29 | — | — | 40–60 days | Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer. |
| Oregano | Nov 10 – Nov 24 | — | Jan 5 – Jan 12 | — | 80–90 days | Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date. |
| Thyme | Nov 10 – Nov 24 | — | Jan 5 – Jan 12 | — | 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 | — | Jan 12 – Jan 26 | — | — | 70–100 days | Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting. |
| Zinnia | Dec 8 – Dec 15 | Jan 12 – Jan 26 | Jan 12 – Jan 19 | — | 60–70 days | Frost-tender; direct sow 1-3 weeks after last frost, or start indoors 3-4 weeks early for earlier blooms. |
| Marigold | Nov 24 – Dec 8 | — | Jan 12 – Jan 19 | — | 45–60 days | Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed. |
| Cosmos | Dec 8 – Dec 15 | Jan 12 – Jan 26 | Jan 12 – Jan 19 | — | 60–90 days | Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early. |
| Nasturtium | — | Jan 12 – Jan 26 | — | — | 50–65 days | Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed. |
| Dahlia | — | — | Jan 12 – Jan 26 | — | 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 Rancho Penasquitos, CA?
Based on 1991–2020 NOAA climate normals for the RANCHO BERNARDO, CA US station, the last spring frost in Rancho Penasquitos typically falls around January 5. A cautious gardener might wait until February 1 (only a 10% chance of a later frost), while December 13 marks an earlier, higher-risk planting date.
When is the first frost in Rancho Penasquitos, CA in fall?
The first fall frost in Rancho Penasquitos typically arrives around January 2. To stay safe, assume frost could start as early as December 13; in milder years it can hold off until January 31.
How long is the growing season in Rancho Penasquitos, CA?
Rancho Penasquitos's average frost-free growing season is about 365 days, running from the typical last spring frost (January 5) to the typical first fall frost (January 2).
What USDA hardiness zone is Rancho Penasquitos, CA in?
Rancho Penasquitos, CA is in USDA plant hardiness zone 10a, 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.