Maricopa, AZ planting calendar
- USDA zone
- 9a20 to 25 °F
- Last frost
- Feb 23avg, 32°F
- First frost
- Nov 24avg, 32°F
- Growing season
- 274days
Maricopa, Arizona is in USDA plant hardiness zone 9a. Its average last spring frost is around February 23 and the first fall frost around November 24, giving a growing season of about 274 days (NOAA 1991–2020 normals, 32°F, median). Start tender crops like tomatoes and peppers indoors weeks before the last frost and set them out afterward; sow hardy crops such as peas, spinach, and lettuce before it. The planner below turns those frost dates into a printable per-crop planting calendar.
Maricopa planting calendar
Each crop's windows are counted from Maricopa's average frost dates. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees.
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting |
|---|---|---|---|---|---|
| Tomato | Tender | Jan 1 – Jan 12 | Mar 2 – Mar 9 | May 1 – May 21 | — |
| Pepper | Very tender | Jan 1 | Mar 9 – Mar 16 | May 8 – Jun 7 | — |
| Cucumber | Tender | Jan 26 – Feb 2 | Mar 2 – Mar 9 | Apr 21 – May 11 | — |
| Summer squash / zucchini | Tender | — | Mar 2 – Mar 9 | Apr 16 – May 1 | — |
| Bush bean | Tender | — | Mar 2 – Mar 9 | Apr 21 – May 1 | Sep 25 – Oct 5 |
| Sweet corn | Tender | — | Feb 23 – Mar 9 | Apr 24 – May 24 | — |
| Basil | Very tender | Jan 12 – Jan 26 | Mar 2 – Mar 9 | Apr 1 – Apr 16 | — |
| Lettuce | Half-hardy | Jan 12 – Jan 26 | Jan 26 – Feb 9 | Mar 12 – Mar 27 | Sep 11 – Sep 26 |
| Pea | Hardy | — | Jan 12 – Jan 26 | Mar 8 – Mar 23 | Sep 1 – Sep 16 |
| Spinach | Hardy | — | Jan 12 – Jan 26 | Feb 21 – Mar 3 | Sep 21 – Oct 1 |
| Carrot | Half-hardy | — | Feb 2 – Feb 9 | Apr 3 – Apr 23 | Aug 22 – Sep 11 |
| Broccoli | Half-hardy | Jan 1 – Jan 12 | Jan 26 – Feb 9 | Mar 22 – Apr 11 | Aug 27 – Sep 16 |
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Frost & freeze dates
From NOAA's 1991–2020 Climate Normals at station USC00025270. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 (p10 for spring, p90 for fall) — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | Mar 12 | Apr 10 | Nov 14 | Nov 28 | 243 |
| 32°F (freeze) | Feb 23 | Mar 15 | Nov 24 | Dec 8 | 274 |
| 28°F | Feb 2 | Feb 28 | Dec 6 | Dec 23 | 310 |
| 24°F | Jan 8 | Feb 8 | Dec 18 | Jan 14 | 345 |
32°F is the standard "freeze" line that damages tender crops; lighter 36°F frost can nip the most cold-sensitive plants, while hardy crops shrug off light frost down toward 28°F. Use the threshold that matches what you are protecting.
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. Warm-season crops need a long, warm GDD total; a short, cool GDD total favors greens and brassicas.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 8,135 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 11,692 | cool-season crops (brassicas, greens) |
Hardiness zone 9a
Maricopa sits in USDA plant hardiness zone 9a on the 2023 map — meaning its average annual extreme minimum winter temperature is about 20 to 25 °F. That number tells you which perennials, shrubs, and trees reliably survive an average winter here; it does not set your planting dates, which come from the frost calendar above.
Explore more places in zone 9a, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Maricopa?
- Maricopa, Arizona is in USDA plant hardiness zone 9a on the 2023 map (average annual extreme minimum temperature 20 to 25 °F) — from the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. See the methodology page for sources.
- When is the last frost in Maricopa?
- The average (median) last spring frost at 32°F is around February 23, from NOAA's 1991–2020 climate normals at the nearest reporting station. Roughly one year in ten the last frost is as late as March 15, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Maricopa?
- The average first fall frost at 32°F is around November 24. That leaves a growing season of about 274 days between the average last spring and first fall frosts.
- When should I start tomatoes in Maricopa?
- Start tomato seeds indoors about Jan 1 – Jan 12 and transplant them outside about Mar 2 – Mar 9, once the danger of frost has passed. Estimated first harvest is around May 1 – May 21.
- How long is the growing season in Maricopa?
- About 274 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~February 23) and the average first fall frost (~November 24). Cold-hardy crops extend usable time at both ends; frost-tender crops fit inside it.
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020 for station USC00025270 (Maricopa 4 N, 11.3 km away). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.