Frost Dates & Planting Calendar for New River, AZ
Plan your garden around New River, AZ's typical frost-free growing season, using NOAA climate normals and a 42-crop planting calendar built for this location.
Last Spring Frost
January 15
Safe Feb 21
Typical Jan 15
Risky Dec 19
First Fall Frost
December 22
Safe Nov 29
Typical Dec 22
Risky Jan 26
Growing Season
341 days
Typical last frost to typical first frost.
USDA Hardiness Zone
Zone 9b
Subtropical to frost-free — heat, not cold, is the main limit on what you can grow.
Data: NOAA station CASTLE HOT SPRINGS, AZ US, 22.2 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 20 – Dec 4 | — | Jan 22 – Jan 29 | — | 60–85 days | Start indoors 6-8 weeks before last frost; transplant out 1-2 weeks after last frost once soil has warmed. |
| Pepper | Nov 6 – Nov 20 | — | Jan 22 – Feb 5 | — | 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 | Nov 6 – Nov 20 | — | Jan 29 – Feb 5 | — | 65–85 days | Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant. |
| Cucumber | Dec 18 – Dec 25 | Jan 22 – Jan 29 | Jan 22 – Jan 29 | — | 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 25 – Jan 1 | Jan 22 – Feb 5 | Jan 22 – Jan 29 | — | 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 18 – Dec 25 | Jan 22 – Feb 5 | Jan 22 – Jan 29 | — | 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 22 – Feb 5 | — | — | 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 18 – Dec 25 | — | Jan 29 – Feb 5 | — | 70–90 days | Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost. |
| Cantaloupe | Dec 18 – Dec 25 | — | Jan 29 – Feb 5 | — | 70–90 days | Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting. |
| Corn | — | Jan 15 – Jan 29 | — | — | 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 15 – Jan 29 | — | — | 50–65 days | Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush. |
| Pea | — | Dec 4 – Dec 18 | — | — | 55–70 days | Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Lettuce | — | Dec 18 – Jan 1 | — | Oct 27 – Nov 10 | 45–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts. |
| Spinach | — | Dec 4 – Dec 18 | — | Oct 27 – Nov 10 | 40–50 days | Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked. |
| Kale | — | Dec 18 – Jan 1 | — | Oct 13 – Oct 27 | 50–65 days | Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants. |
| Arugula | — | Dec 18 – Jan 1 | — | Nov 10 – Nov 17 | 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 25 – Jan 8 | — | — | 50–60 days | Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too. |
| Broccoli | Nov 27 – Dec 11 | — | Dec 25 – Jan 1 | Oct 20 – Oct 27 | 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 27 – Dec 11 | — | Jan 1 – Jan 8 | Oct 13 – Oct 20 | 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 27 – Dec 11 | — | Dec 18 – Jan 1 | Oct 13 – Oct 27 | 60–100 days | Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost. |
| Brussels Sprouts | Nov 27 – Dec 11 | — | Dec 25 – Jan 8 | — | 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 18 – Jan 1 | — | Sep 29 – Oct 13 | 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 18 – Jan 1 | — | Oct 13 – Oct 27 | 50–65 days | Direct sow 2-4 weeks before last frost; tolerates light frost. |
| Radish | — | Dec 11 – Dec 25 | — | Nov 10 – Nov 24 | 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 18 – Jan 1 | — | Oct 13 – Oct 27 | 40–60 days | Cold-hardy; direct sow 2-4 weeks before last frost. |
| Onion | Nov 6 – Nov 20 | — | Dec 18 – Jan 1 | — | 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 | — | — | — | Nov 24 – Dec 8 | 240–270 days | Fall-planted crop only; not planted in spring in most climates. |
| Potato | — | Dec 18 – Jan 1 | — | — | 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 29 – Feb 12 | — | 90–120 days | Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive. |
| Asparagus | — | — | Dec 18 – Jan 1 | — | 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 | Dec 4 – Dec 11 | — | Jan 22 – Jan 29 | — | 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 25 – Jan 8 | — | Oct 27 – Nov 10 | 45–70 days | Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring. |
| Parsley | Nov 20 – Dec 4 | — | Jan 1 – Jan 8 | — | 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 25 – Jan 8 | — | — | 40–60 days | Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer. |
| Oregano | Nov 20 – Dec 4 | — | Jan 15 – Jan 22 | — | 80–90 days | Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date. |
| Thyme | Nov 20 – Dec 4 | — | Jan 15 – Jan 22 | — | 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 22 – Feb 5 | — | — | 70–100 days | Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting. |
| Zinnia | Dec 18 – Dec 25 | Jan 22 – Feb 5 | Jan 22 – Jan 29 | — | 60–70 days | Frost-tender; direct sow 1-3 weeks after last frost, or start indoors 3-4 weeks early for earlier blooms. |
| Marigold | Dec 4 – Dec 18 | — | Jan 22 – Jan 29 | — | 45–60 days | Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed. |
| Cosmos | Dec 18 – Dec 25 | Jan 22 – Feb 5 | Jan 22 – Jan 29 | — | 60–90 days | Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early. |
| Nasturtium | — | Jan 22 – Feb 5 | — | — | 50–65 days | Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed. |
| Dahlia | — | — | Jan 22 – Feb 5 | — | 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 New River, AZ?
Based on 1991–2020 NOAA climate normals for the CASTLE HOT SPRINGS, AZ US station, the last spring frost in New River typically falls around January 15. A cautious gardener might wait until February 21 (only a 10% chance of a later frost), while December 19 marks an earlier, higher-risk planting date.
When is the first frost in New River, AZ in fall?
The first fall frost in New River typically arrives around December 22. To stay safe, assume frost could start as early as November 29; in milder years it can hold off until January 26.
How long is the growing season in New River, AZ?
New River's average frost-free growing season is about 341 days, running from the typical last spring frost (January 15) to the typical first fall frost (December 22).
What USDA hardiness zone is New River, AZ in?
New River, AZ is in USDA plant hardiness zone 9b, 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.