The four dates that matter
| Date | When | What it means |
|---|---|---|
| Last spring frost (50%) | Jan 8 | Half of all years see a freeze after this date. It is an average, not a guarantee. |
| Last spring frost (10%) | Feb 12 | Only one year in ten freezes after this. Use it for anything you cannot afford to replant. |
| First fall frost (50%) | Dec 25 | Half of all years freeze before this date. Fall crops are counted back from here. |
| First fall frost (10%) | Dec 5 | An early-freeze year. If a crop must finish, aim to harvest before this. |
Spring & summer planting in Phoenix
A mild-winter note. Phoenix's last frost lands so early that several of these windows fall in late autumn of the previous calendar year โ that is not a mistake, it is how a long season works here. Read this table together with the fall one below rather than as two separate seasons.
Dates are calculated from this location's own last-frost date, not from a generic zone chart. โBest moon daysโ are the days inside each window that fall in the crop's traditional phase โ the same rule the app uses.
| Crop | Start seed indoors | Plant outdoors | Best moon days | Days to harvest |
|---|---|---|---|---|
| Cucumber either |
Dec 18 | Jan 8 โ Feb 7 | Jan 25 First Quarter |
50โ70 |
| Green Beans (bush) direct sow |
โ | Jan 8 โ Feb 22 | Jan 25 First Quarter |
50โ65 |
| Oregano transplant |
Nov 13 | Jan 8 โ Jan 29 | Jan 25 First Quarter |
cut as needed |
| Sage transplant |
Nov 13 | Jan 8 โ Jan 29 | Jan 25 First Quarter |
cut as needed |
| Sweet Corn direct sow |
โ | Jan 8 โ Feb 22 | Jan 25 First Quarter |
60โ100 |
| Thyme transplant |
Nov 13 | Jan 8 โ Jan 29 | Jan 25 First Quarter |
cut as needed |
| Zucchini / Summer Squash either |
Dec 18 | Jan 8 โ Feb 7 | Jan 25 First Quarter |
45โ60 |
| Basil either |
Nov 27 | Jan 15 โ Feb 7 | Jan 19โ24 Waxing Crescent |
30โ60 |
| Dry Beans direct sow |
โ | Jan 15 โ Feb 12 | Jan 25 First Quarter |
85โ100 |
| Pole Beans direct sow |
โ | Jan 15 โ Feb 17 | Jan 25 First Quarter |
60โ75 |
| Pumpkin direct sow |
Dec 18 | Jan 15 โ Feb 12 | Jan 25 First Quarter |
90โ120 |
| Rosemary transplant |
Jan 8 | Jan 15 โ Feb 7 | Jan 25 First Quarter |
cut as needed |
| Tomatillo transplant |
Nov 27 | Jan 15 โ Feb 7 | Jan 25 First Quarter |
60โ75 |
| Tomato transplant |
Nov 27 | Jan 15 โ Feb 7 | Jan 25 First Quarter |
60โ85 |
| Winter Squash direct sow |
Dec 18 | Jan 15 โ Feb 12 | Jan 25 First Quarter |
85โ110 |
| Cantaloupe / Muskmelon either |
Dec 18 | Jan 22 โ Feb 12 | Jan 25 First Quarter |
75โ90 |
| Eggplant transplant |
Nov 13 | Jan 22 โ Feb 12 | Jan 25 First Quarter |
60โ90 |
| Okra direct sow |
Dec 11 | Jan 22 โ Feb 17 | Jan 25 First Quarter |
50โ70 |
| Pepper transplant |
Nov 13 | Jan 22 โ Feb 12 | Jan 25 First Quarter |
60โ90 |
| Sweet Potato slips |
โ | Jan 22 โ Feb 17 | Feb 2โ7 Waning Gibbous |
90โ150 |
| Watermelon either |
Dec 18 | Jan 22 โ Feb 12 | Jan 25 First Quarter |
70โ90 |
| Strawberry (crowns) transplant |
โ | Nov 9 โ Dec 18 | Dec 4 Full Moon |
perennial โ first real harvest next season |
| Garlic cloves/sets Better planted in fall โ see below |
โ | Nov 22 โ Dec 23 | Dec 5โ10 Waning Gibbous |
240โ300 |
| Asparagus (crowns) transplant |
โ | Nov 27 โ Jan 1 | Nov 27, Dec 27 First Quarter |
perennial โ first real harvest 2โ3 years |
| Chives either |
Nov 13 | Nov 27 โ Jan 1 | Dec 20โ25 Waxing Crescent |
75โ90 |
| Onion (from sets/transplants) cloves/sets |
โ | Nov 27 โ Jan 1 | Dec 5โ10 Waning Gibbous |
90โ120 |
| Peas (English/snap) direct sow |
โ | Nov 27 โ Jan 1 | Nov 27, Dec 27 First Quarter |
55โ75 |
| Spinach direct sow |
โ | Nov 27 โ Jan 1 | Dec 20โ25 Waxing Crescent |
35โ50 |
| Cabbage transplant |
Nov 6 | Dec 4 โ Jan 1 | Dec 20โ25 Waxing Crescent |
65โ90 |
| Collards either |
Nov 27 | Dec 4 โ Jan 22 | Dec 20โ25 Waxing Crescent |
55โ85 |
| Kale either |
Nov 27 | Dec 4 โ Jan 8 | Dec 20โ25 Waxing Crescent |
50โ65 |
| Lettuce (leaf) either |
Dec 4 | Dec 4 โ Jan 29 | Dec 20โ25 Waxing Crescent |
40โ55 |
| Potato cloves/sets |
โ | Dec 4 โ Jan 8 | Dec 4, Jan 3 Full Moon |
70โ120 |
| Radish direct sow |
โ | Dec 4 โ Jan 29 | Dec 5โ10 Waning Gibbous |
22โ35 |
| Turnip direct sow |
โ | Dec 4 โ Jan 15 | Dec 5โ10 Waning Gibbous |
40โ60 |
| Broccoli transplant |
Nov 6 | Dec 9 โ Jan 8 | Dec 20โ25 Waxing Crescent |
55โ80 |
| Brussels Sprouts transplant |
Nov 6 | Dec 9 โ Jan 8 | Dec 20โ25 Waxing Crescent |
90โ110 |
| Leek transplant |
Oct 30 | Dec 9 โ Jan 8 | Dec 9โ10, Jan 4โ7 Waning Gibbous |
100โ120 |
| Lettuce (head) transplant |
Nov 20 | Dec 9 โ Jan 8 | Dec 20โ25 Waxing Crescent |
60โ85 |
| Parsley either |
Nov 6 | Dec 9 โ Jan 15 | Dec 20โ25 Waxing Crescent |
70โ90 |
| Parsnip direct sow |
โ | Dec 9 โ Jan 15 | Jan 3 Full Moon |
100โ150 |
| Shallot cloves/sets Better planted in fall โ see below |
โ | Dec 9 โ Jan 8 | Dec 9โ10, Jan 4โ7 Waning Gibbous |
90โ120 |
| Beet direct sow |
โ | Dec 11 โ Jan 29 | Jan 3 Full Moon |
50โ65 |
| Kohlrabi either |
Nov 27 | Dec 11 โ Jan 15 | Dec 20โ25 Waxing Crescent |
45โ60 |
| Carrot direct sow |
โ | Dec 18 โ Jan 29 | Jan 3 Full Moon |
65โ85 |
| Cauliflower transplant |
Nov 6 | Dec 18 โ Jan 8 | Dec 20โ25 Waxing Crescent |
55โ80 |
| Cilantro direct sow |
โ | Dec 18 โ Jan 29 | Dec 20โ25 Waxing Crescent |
45โ70 |
| Swiss Chard direct sow |
โ | Dec 18 โ Feb 7 | Dec 20โ25 Waxing Crescent |
50โ60 |
| Dill direct sow |
โ | Dec 25 โ Feb 7 | Dec 25โ26, Jan 19โ22 Waxing Crescent |
40โ60 |
Fall planting in Phoenix
Fall dates count backward from the first frost, and they add time back for the โfall factorโ โ days are shortening and cooling, so a crop grows slower than the seed packet promises. Sowing late is the single most common way a fall garden fails.
| Crop | Sow or set out | Best moon days | Days to harvest | Hardiness |
|---|---|---|---|---|
| Tomato | Aug 9 โ Sep 14 | Aug 19 | 60โ85 | very tender |
| Brussels Sprouts | Aug 12 โ Aug 29 | Aug 13โ18 | 90โ110 | hardy |
| Potato | Aug 17 โ Sep 18 | Aug 27 | 70โ120 | semi-hardy |
| Sweet Corn | Aug 22 โ Sep 14 | โ | 60โ100 | tender |
| Pole Beans | Sep 1 โ Sep 14 | โ | 60โ75 | tender |
| Parsley | Sep 4 โ Sep 18 | Sep 11โ16 | 70โ90 | semi-hardy |
| Okra | Sep 6 โ Oct 6 | Sep 18 | 50โ70 | very tender |
| Cabbage | Sep 11 โ Sep 23 | Sep 11โ16 | 65โ90 | hardy |
| Carrot | Sep 11 โ Sep 23 | โ | 65โ85 | semi-hardy |
| Collards | Sep 11 โ Oct 3 | Sep 11โ16 | 55โ85 | hardy |
| Cucumber | Sep 11 โ Sep 24 | Sep 18 | 50โ70 | tender |
| Broccoli | Sep 16 โ Oct 3 | Sep 16โ17 | 55โ80 | hardy |
| Cauliflower | Sep 16 โ Oct 3 | Sep 16โ17 | 55โ80 | semi-hardy |
| Green Beans (bush) | Sep 16 โ Sep 24 | Sep 18 | 50โ65 | tender |
| Lettuce (head) | Sep 16 โ Sep 28 | Sep 16โ17 | 60โ85 | semi-hardy |
| Peas (English/snap) | Sep 16 โ Oct 3 | Sep 18 | 55โ75 | hardy |
| Beet | Sep 21 โ Oct 8 | Sep 26 | 50โ65 | semi-hardy |
| Kale | Sep 21 โ Oct 8 | โ | 50โ65 | hardy |
| Swiss Chard | Sep 21 โ Oct 8 | โ | 50โ60 | semi-hardy |
| Zucchini / Summer Squash | Sep 21 โ Sep 29 | โ | 45โ60 | tender |
| Basil | Sep 26 โ Oct 14 | Oct 11โ14 | 30โ60 | very tender |
| Kohlrabi | Sep 26 โ Oct 13 | Oct 11โ13 | 45โ60 | hardy |
| Cilantro | Oct 1 โ Oct 13 | Oct 11โ13 | 45โ70 | semi-hardy |
| Lettuce (leaf) | Oct 1 โ Oct 18 | Oct 11โ16 | 40โ55 | semi-hardy |
| Turnip | Oct 1 โ Oct 18 | Oct 1โ2 | 40โ60 | hardy |
| Spinach | Oct 6 โ Oct 23 | Oct 11โ16 | 35โ50 | hardy |
| Dill | Oct 11 โ Oct 18 | Oct 11โ16 | 40โ60 | semi-hardy |
| Radish | Oct 11 โ Nov 5 | Oct 26โ31 | 22โ35 | hardy |
| Garlic | Nov 25 โ Jan 15 | Nov 25โ29, Dec 24 | 240โ300 | hardy |
| Shallot | Dec 9 โ Jan 9 | Dec 24โ29 | 90โ120 | hardy |
Where these numbers come from
The frost dates on this page are observed station normals, not estimates: they come from Phoenix Deer Valley Muni Ap (GHCN USW00003184), one of 6,808 U.S. stations in NOAA's 1991โ2020 Climate Normals. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map. Crop timing is expressed as offsets from your frost dates, drawn from university Extension planting guides.
How precise is any of this?
Extension recommendations for the same crop routinely disagree by two to four weeks, and occasionally more, so these offsets should be presented as windows and starting points rather than deadlines. Three things drive the spread. (1) Regional risk tolerance: for warm-season crops, Colorado State and Utah State put tomatoes, peppers and melons out about 14 days after the last frost, while University of Missouri's calendar works out to roughly 25-35 days after the last frost and University of Maryland's window runs from the frost date itself out to 45 days past it. That is a real 6-week spread for the single most popular garden crop, and it exists because a short-season mountain state is optimizing against a short season while a humid continental state is optimizing against cold, wet spring soil. (2) Soil temperature versus calendar date: most Extension services now say the honest trigger is soil temperature at 4 inches, not the frost date, and the frost-relative number is a convenience translation. A cold, wet spring can push the real date two or three weeks past the calendar recommendation. (3) Days-to-maturity is variety-specific and is measured differently for direct-seeded versus transplanted crops - seed catalogs count from transplant date for tomatoes, peppers, eggplant and cole crops, but from sowing for roots and greens - so a 'days to maturity' range of 60-85 for tomato is genuinely 60-85 depending on which packet you bought. Additionally, the average last frost is a 50% probability, meaning half of all years have a frost after that date; Extension services commonly advise waiting 1-2 weeks past it for anything frost-tender, or being prepared to cover. Treat every number here as plus or minus about 10-14 days.
On the station itself: a weather station is one point. Cities hold their heat, valleys pool cold air, and a garden on a north slope can run two weeks behind one a mile away. Treat this page as your starting point and let your own garden correct it โ that is exactly what the journal in the app is for.
Nearby locations
Planting reminders for Phoenix
A short note at each new and full moon telling you what is in its window right now for Phoenix โ worked out from the frost dates on this page. Free, one click to stop.
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