Mesa, AZ Vegetable Planting Calendar
Here are planting dates for 26 vegetables in Mesa, for the 2027 season, based on 1991–2020 normals. We start from the 32°F frost odds at E Mesa (4.3 mi ENE) and apply CSU Extension timing rules, each listed below with its source.
NOAA puts the yearly chance of at least one 32°F night at E Mesa at 98.2%. The dates below come from the frost odds for the years that do freeze.
These are Colorado State University Extension (spring) and University of Nebraska–Lincoln Extension (fall) timing rules, applied to Mesa's own NOAA frost dates. Arizona extension guidance may differ, so check it too.
Frost anchors: typical last frost Feb 1 (50%), balanced Feb 12 (30%), safe Feb 28 (10%); typical first frost Dec 10. Station E Mesa (USC00022782), confidence Medium. USDA zone 9b–10a (2023). Mesa frost dates & growing zone.
What to plant now in Mesa
In October:
- Last day to sow kohlrabi for a fall harvest (by Oct 7)
- Last day to sow turnips for a fall harvest (by Oct 7)
- Last day to sow spinach for a fall harvest (by Oct 17)
- Last day to sow radishes for a fall harvest (by Oct 27)
The list above is for the month this page was built; the box is refreshed in your browser for today's date.
Spring planting dates
“Plant out” means transplanting for crops started indoors and sowing or planting directly in the garden for the others. Each column applies CSU Extension's timing rule to a different last-frost anchor: aggressive = typical date (Feb 1, 50% risk), balanced = Feb 12 (30%), safe = Feb 28 (10%). For hardy crops the cell shows the CSU “as early as” window.
| Crop | How | Start indoors | Plant out: aggressive (50%) | Balanced (30%) | Safe (10%) | Min. soil temp |
|---|---|---|---|---|---|---|
| Tomatoes Very tender (warm season) |
transplant | Feb 22 – Mar 8 | Apr 12 | Apr 12 | Apr 12 | 50°F |
| Peppers Very tender (warm season) |
transplant | Jan 1–15 | Feb 15 | Feb 26 | Mar 14 | 60°F |
| Potatoes Semi-hardy (cool season) |
plant (seed pieces) | – | Jan 18 – Feb 1 | Jan 29 – Feb 12 | Feb 14–28 | 45°F |
| Onions (dry, from sets) Hardy (cool season) |
plant sets | – | Jan 4–18 | Jan 15–29 | Jan 31 – Feb 14 | 35°F |
| Peas Hardy (cool season) |
direct sow | – | Jan 4–18 | Jan 15–29 | Jan 31 – Feb 14 | 40°F |
| Lettuce (leaf) Hardy (cool season) |
direct sow | – | Jan 4–18 | Jan 15–29 | Jan 31 – Feb 14 | 35°F |
| Carrots Semi-hardy (cool season) |
direct sow | – | Jan 18 – Feb 1 | Jan 29 – Feb 12 | Feb 14–28 | 40°F |
| Beans (snap) Tender (warm season) |
direct sow | – | Feb 1 | Feb 12 | Feb 28 | 55°F |
| Summer squash Tender (warm season) |
direct sow | – | Feb 1 | Feb 12 | Feb 28 | 60°F |
| Broccoli Hardy (cool season) |
transplant | Nov 27 – Dec 11 | Jan 4–18 | Jan 15–29 | Jan 31 – Feb 14 | 40°F |
| Cabbage Hardy (cool season) |
transplant | Nov 27 – Dec 11 | Jan 4–18 | Jan 15–29 | Jan 31 – Feb 14 | 40°F |
| Cauliflower Semi-hardy (cool season) |
transplant | Dec 11–25 | Jan 18 – Feb 1 | Jan 29 – Feb 12 | Feb 14–28 | 40°F |
| Kohlrabi Hardy (cool season) |
direct sow | – | Jan 4–18 | Jan 15–29 | Jan 31 – Feb 14 | 40°F |
| Green onions Hardy (cool season) |
direct sow | – | Jan 4–18 | Jan 15–29 | Jan 31 – Feb 14 | 35°F |
| Radishes Hardy (cool season) |
direct sow | – | Jan 4–18 | Jan 15–29 | Jan 31 – Feb 14 | 40°F |
| Spinach Hardy (cool season) |
direct sow | – | Jan 4–18 | Jan 15–29 | Jan 31 – Feb 14 | 40°F |
| Turnips Hardy (cool season) |
direct sow | – | Jan 4–18 | Jan 15–29 | Jan 31 – Feb 14 | 40°F |
| Beets Semi-hardy (cool season) |
direct sow | – | Jan 18 – Feb 1 | Jan 29 – Feb 12 | Feb 14–28 | 40°F |
| Swiss chard Semi-hardy (cool season) |
direct sow | – | Jan 18 – Feb 1 | Jan 29 – Feb 12 | Feb 14–28 | 40°F |
| Parsnips Semi-hardy (cool season) |
direct sow | – | Jan 18 – Feb 1 | Jan 29 – Feb 12 | Feb 14–28 | 35°F |
| Sweet corn Tender (warm season) |
direct sow | – | Feb 1 | Feb 12 | Feb 28 | 50°F |
| Cucumbers Tender (warm season) |
direct sow | – | Feb 1 | Feb 12 | Feb 28 | 60°F |
| Eggplant Very tender (warm season) |
transplant | Dec 25 – Jan 15 | Feb 15 | Feb 26 | Mar 14 | 60°F |
| Cantaloupe Very tender (warm season) |
direct sow | – | Feb 15 | Feb 26 | Mar 14 | 60°F |
| Watermelon Very tender (warm season) |
direct sow | – | Feb 15 | Feb 26 | Mar 14 | 60°F |
| Winter squash Very tender (warm season) |
direct sow | – | Feb 15 | Feb 26 | Mar 14 | 60°F |
Before sowing, check the soil too. CSU recommends taking its temperature at 4 inches (6 inches for beans). Since NOAA publishes no soil-temperature normals, we give CSU's minimum soil temperature for each crop rather than a date.
Fall planting dates
Latest dates for a fall harvest, using the University of Nebraska–Lincoln Extension count-back formula: days to harvest (CSU) + 14-day fall factor + 14-day frost-tender factor for frost-sensitive crops, counted back from the first-frost date. For transplanted crops (CSU days are from transplant) the result is the latest transplant date; seeds go in CSU's transplant-age weeks earlier. We add no harvest period, so these dates give you a first harvest by the first frost, not a long harvest.
| Crop | How | Days counted back | By (typical first frost Dec 10) | By (early first frost Nov 22) |
|---|---|---|---|---|
| Peas | sow | 79 | Sep 22 | Sep 4 |
| Lettuce (leaf) | sow | 74 | Sep 27 | Sep 9 |
| Carrots | sow | 84 | Sep 17 | Aug 30 |
| Beans (snap) | sow | 88 (frost-tender) | Sep 13 | Aug 26 |
| Summer squash | sow | 78 (frost-tender) | Sep 23 | Sep 5 |
| Broccoli | transplant (start seeds Aug 4–18) | 79 | Sep 22 | Sep 4 |
| Cabbage | transplant (start seeds Jul 15–29) | 99 | Sep 2 | Aug 15 |
| Kohlrabi | sow | 64 | Oct 7 | Sep 19 |
| Green onions | sow | 74 | Sep 27 | Sep 9 |
| Radishes | sow | 44 | Oct 27 | Oct 9 |
| Spinach | sow | 54 | Oct 17 | Sep 29 |
| Turnips | sow | 64 | Oct 7 | Sep 19 |
| Beets | sow | 74 | Sep 27 | Sep 9 |
| Swiss chard | sow | 74 | Sep 27 | Sep 9 |
| Cucumbers | sow | 83 (frost-tender) | Sep 18 | Aug 31 |
Month-by-month: what to plant in Mesa
What to plant in Mesa in January
- Start pepper seeds indoors (Jan 1–15)
- Onions (dry, from sets): plant sets outdoors (Jan 4 – Feb 14)
- Peas: direct sow outdoors (Jan 4 – Feb 14)
- Lettuce (leaf): direct sow outdoors (Jan 4 – Feb 14)
- Broccoli: transplant outdoors (Jan 4 – Feb 14)
- Cabbage: transplant outdoors (Jan 4 – Feb 14)
- Kohlrabi: direct sow outdoors (Jan 4 – Feb 14)
- Green onions: direct sow outdoors (Jan 4 – Feb 14)
- Radishes: direct sow outdoors (Jan 4 – Feb 14)
- Spinach: direct sow outdoors (Jan 4 – Feb 14)
- Turnips: direct sow outdoors (Jan 4 – Feb 14)
- Potatoes: plant (seed pieces) outdoors (Jan 18 – Feb 28)
- Carrots: direct sow outdoors (Jan 18 – Feb 28)
- Cauliflower: transplant outdoors (Jan 18 – Feb 28)
- Beets: direct sow outdoors (Jan 18 – Feb 28)
- Swiss chard: direct sow outdoors (Jan 18 – Feb 28)
- Parsnips: direct sow outdoors (Jan 18 – Feb 28)
- Start eggplant seeds indoors (Dec 25 – Jan 15)
What to plant in Mesa in February
- Beans (snap): direct sow outdoors (Feb 1–28)
- Summer squash: direct sow outdoors (Feb 1–28)
- Sweet corn: direct sow outdoors (Feb 1–28)
- Cucumbers: direct sow outdoors (Feb 1–28)
- Peppers: transplant outdoors (Feb 15 – Mar 14)
- Eggplant: transplant outdoors (Feb 15 – Mar 14)
- Cantaloupe: direct sow outdoors (Feb 15 – Mar 14)
- Watermelon: direct sow outdoors (Feb 15 – Mar 14)
- Winter squash: direct sow outdoors (Feb 15 – Mar 14)
- Start tomato seeds indoors (Feb 22 – Mar 8)
- Onions (dry, from sets): plant sets outdoors (Jan 4 – Feb 14)
- Peas: direct sow outdoors (Jan 4 – Feb 14)
- Lettuce (leaf): direct sow outdoors (Jan 4 – Feb 14)
- Broccoli: transplant outdoors (Jan 4 – Feb 14)
- Cabbage: transplant outdoors (Jan 4 – Feb 14)
- Kohlrabi: direct sow outdoors (Jan 4 – Feb 14)
- Green onions: direct sow outdoors (Jan 4 – Feb 14)
- Radishes: direct sow outdoors (Jan 4 – Feb 14)
- Spinach: direct sow outdoors (Jan 4 – Feb 14)
- Turnips: direct sow outdoors (Jan 4 – Feb 14)
- Potatoes: plant (seed pieces) outdoors (Jan 18 – Feb 28)
- Carrots: direct sow outdoors (Jan 18 – Feb 28)
- Cauliflower: transplant outdoors (Jan 18 – Feb 28)
- Beets: direct sow outdoors (Jan 18 – Feb 28)
- Swiss chard: direct sow outdoors (Jan 18 – Feb 28)
- Parsnips: direct sow outdoors (Jan 18 – Feb 28)
What to plant in Mesa in March
- Peppers: transplant outdoors (Feb 15 – Mar 14)
- Eggplant: transplant outdoors (Feb 15 – Mar 14)
- Cantaloupe: direct sow outdoors (Feb 15 – Mar 14)
- Watermelon: direct sow outdoors (Feb 15 – Mar 14)
- Winter squash: direct sow outdoors (Feb 15 – Mar 14)
- Start tomato seeds indoors (Feb 22 – Mar 8)
What to plant in Mesa in April
- Tomatoes: transplant outdoors (Apr 12)
What to plant in Mesa in July
- Start cabbage seeds indoors for a fall crop (Jul 15–29)
What to plant in Mesa in August
- Start broccoli seeds indoors for a fall crop (Aug 4–18)
What to plant in Mesa in September
- Last day to set out cabbage transplants for a fall harvest (by Sep 2)
- Last day to sow beans (snap) for a fall harvest (by Sep 13)
- Last day to sow carrots for a fall harvest (by Sep 17)
- Last day to sow cucumbers for a fall harvest (by Sep 18)
- Last day to sow peas for a fall harvest (by Sep 22)
- Last day to set out broccoli transplants for a fall harvest (by Sep 22)
- Last day to sow summer squash for a fall harvest (by Sep 23)
- Last day to sow lettuce (leaf) for a fall harvest (by Sep 27)
- Last day to sow green onions for a fall harvest (by Sep 27)
- Last day to sow beets for a fall harvest (by Sep 27)
- Last day to sow swiss chard for a fall harvest (by Sep 27)
What to plant in Mesa in October
- Last day to sow kohlrabi for a fall harvest (by Oct 7)
- Last day to sow turnips for a fall harvest (by Oct 7)
- Last day to sow spinach for a fall harvest (by Oct 17)
- Last day to sow radishes for a fall harvest (by Oct 27)
What to plant in Mesa in November
- Start broccoli seeds indoors (Nov 27 – Dec 11)
- Start cabbage seeds indoors (Nov 27 – Dec 11)
What to plant in Mesa in December
- Start cauliflower seeds indoors (Dec 11–25)
- Start eggplant seeds indoors (Dec 25 – Jan 15)
- Start broccoli seeds indoors (Nov 27 – Dec 11)
- Start cabbage seeds indoors (Nov 27 – Dec 11)
Crop-by-crop notes
When to plant tomatoes in Mesa
Very tender crop. Set tomatoes out about Apr 12, whichever risk level you go by. That date comes from CSU Extension's night rule (nights above 52°F): the average nightly low at E Mesa first rises above 52°F on Apr 12. CSU's other rule, at least 2 weeks after the average last frost, would allow about Feb 15 in Mesa. Sow seeds indoors Feb 22 – Mar 8, 5–7 weeks before transplanting on Apr 12. Fruit set suffers when nights drop below 55°F (CSU). The normal low at E Mesa reaches 55°F on Apr 23. CSU's typical time from transplant to harvest for tomato plants is 65 days. Set out on Apr 12, they would start producing around Jun 16, 177 days before the typical first frost (Dec 10).
When to plant peppers in Mesa
Very tender crop. CSU Extension's rule is 2+ weeks after the average last frost, which puts peppers outside around Feb 15 (typical date), Feb 26 (balanced) or Mar 14 (safer 10% date). Start seeds indoors Jan 1–15, 6–8 weeks ahead of transplanting on Feb 26. CSU notes that nights under 55°F hurt fruit set. The normal low at E Mesa climbs to 55°F on Apr 23. Set out on Feb 26, pepper plants would start producing around May 7, based on CSU's typical 70 days from transplant to harvest. That leaves 217 days before the typical first frost (Dec 10).
When to plant potatoes in Mesa
Semi-hardy crop. CSU allows planting potatoes as early as 0–2 weeks before the average last frost, in soil at 45°F or warmer. For Mesa, that's roughly Jan 18 – Feb 1 by the typical date or Feb 14–28 by the safer date.
When to plant onions (dry, from sets) in Mesa
Hardy crop. CSU says onions (dry, from sets) can go in as early as 2–4 weeks before the average last frost, once the soil can be worked and is at least 35°F. In Mesa, that's roughly Jan 4–18 going by the typical date, or Jan 31 – Feb 14 going by the safer date.
When to plant peas in Mesa
Hardy crop. CSU says peas can go in as early as 2–4 weeks before the average last frost, once the soil can be worked and is at least 40°F. In Mesa, that's roughly Jan 4–18 going by the typical date, or Jan 31 – Feb 14 going by the safer date. For fall, sow by Sep 22 (Sep 4 to be safe), which is 79 days before the first-frost date.
When to plant lettuce (leaf) in Mesa
Hardy crop. CSU says lettuce (leaf) can go in as early as 2–4 weeks before the average last frost: roughly Jan 4–18 in Mesa using the typical date, or Jan 31 – Feb 14 using the safer one. Wait until the soil can be worked and is at least 35°F. For fall, count back 74 days from the first-frost date. That means sowing by Sep 27, or by Sep 9 to be safe.
When to plant carrots in Mesa
Semi-hardy crop. Per CSU, carrots can go in as early as 0–2 weeks before the average last frost: roughly Jan 18 – Feb 1 in Mesa (typical date) or Feb 14–28 (safer date). The soil should be at least 40°F. For a fall crop, sow by Sep 17, or by Aug 30 to be safe. That's 84 days back from the first-frost date.
When to plant beans (snap) in Mesa
Tender crop. CSU's timing for beans (snap) is around the average last frost, which is about Feb 1 in Mesa. For only a 1-in-10 chance of a later 32°F night, hold off until Feb 28. Seeds want soil at 55°F or warmer. For a fall crop, sow by Sep 13, or by Aug 26 to be safe. That's 88 days back from the first-frost date.
When to plant summer squash in Mesa
Tender crop. Sow summer squash around the average last frost, per CSU: about Feb 1 in Mesa. Waiting until Feb 28 cuts the chance of a later 32°F night to 1 in 10. Seeds need soil of at least 60°F. For a fall crop, sow by Sep 23, or by Sep 5 to be safe. That's 78 days back from the first-frost date.
When to plant broccoli in Mesa
Hardy crop. CSU says broccoli can go in as early as 2–4 weeks before the average last frost, once the soil can be worked and is at least 40°F. In Mesa, that's roughly Jan 4–18 going by the typical date, or Jan 31 – Feb 14 going by the safer date. Set out on Jan 15, broccoli plants would start producing around Mar 21, based on CSU's typical 65 days from transplant to harvest. That leaves 264 days before the typical first frost (Dec 10). For a fall harvest of broccoli, get transplants in the ground by Sep 22 (UNL Extension count-back from the typical first frost, Dec 10, with CSU's 65 days from transplant to harvest). To raise your own, sow seeds Aug 4–18, 5–7 weeks ahead (CSU).
When to plant cabbage in Mesa
Hardy crop. Per CSU, cabbage can be planted as early as 2–4 weeks before the average last frost, as long as the soil is workable and at least 40°F. For Mesa, that works out to roughly Jan 4–18 (typical date) or Jan 31 – Feb 14 (safer date). CSU's typical time from transplant to harvest for cabbage plants is 85 days. Set out on Jan 15, they would start producing around Apr 10, 244 days before the typical first frost (Dec 10). For a fall harvest of cabbage, get transplants in the ground by Sep 2 (UNL Extension count-back from the typical first frost, Dec 10, with CSU's 85 days from transplant to harvest). To raise your own, sow seeds Jul 15–29, 5–7 weeks ahead (CSU).
When to plant cauliflower in Mesa
Semi-hardy crop. CSU says cauliflower can be planted as early as 0–2 weeks before the average last frost, in soil of at least 40°F. In Mesa, that's roughly Jan 18 – Feb 1 going by the typical date, or Feb 14–28 going by the safer date.
When to plant kohlrabi in Mesa
Hardy crop. CSU says kohlrabi can go in as early as 2–4 weeks before the average last frost, once the soil can be worked and is at least 40°F. In Mesa, that's roughly Jan 4–18 going by the typical date, or Jan 31 – Feb 14 going by the safer date. For fall, count back 64 days from the first-frost date. That means sowing by Oct 7, or by Sep 19 to be safe.
When to plant green onions in Mesa
Hardy crop. CSU says green onions can go in as early as 2–4 weeks before the average last frost, once the soil can be worked and is at least 35°F. In Mesa, that's roughly Jan 4–18 going by the typical date, or Jan 31 – Feb 14 going by the safer date. For fall, count back 74 days from the first-frost date. That means sowing by Sep 27, or by Sep 9 to be safe.
When to plant radishes in Mesa
Hardy crop. Per CSU, radishes can be planted as early as 2–4 weeks before the average last frost, as long as the soil is workable and at least 40°F. For Mesa, that works out to roughly Jan 4–18 (typical date) or Jan 31 – Feb 14 (safer date). For fall, sow by Oct 27 (Oct 9 to be safe), which is 44 days before the first-frost date.
When to plant spinach in Mesa
Hardy crop. CSU says spinach can go in as early as 2–4 weeks before the average last frost, once the soil can be worked and is at least 40°F. In Mesa, that's roughly Jan 4–18 going by the typical date, or Jan 31 – Feb 14 going by the safer date. For fall, count back 54 days from the first-frost date. That means sowing by Oct 17, or by Sep 29 to be safe.
When to plant turnips in Mesa
Hardy crop. CSU says turnips can go in as early as 2–4 weeks before the average last frost, once the soil can be worked and is at least 40°F. In Mesa, that's roughly Jan 4–18 going by the typical date, or Jan 31 – Feb 14 going by the safer date. For fall, count back 64 days from the first-frost date. That means sowing by Oct 7, or by Sep 19 to be safe.
When to plant beets in Mesa
Semi-hardy crop. Per CSU, beets can go in as early as 0–2 weeks before the average last frost: roughly Jan 18 – Feb 1 in Mesa (typical date) or Feb 14–28 (safer date). The soil should be at least 40°F. For fall, count back 74 days from the first-frost date. That means sowing by Sep 27, or by Sep 9 to be safe.
When to plant swiss chard in Mesa
Semi-hardy crop. Per CSU, swiss chard can go in as early as 0–2 weeks before the average last frost: roughly Jan 18 – Feb 1 in Mesa (typical date) or Feb 14–28 (safer date). The soil should be at least 40°F. For a fall crop, sow by Sep 27, or by Sep 9 to be safe. That's 74 days back from the first-frost date.
When to plant parsnips in Mesa
Semi-hardy crop. Per CSU, parsnips can go in as early as 0–2 weeks before the average last frost: roughly Jan 18 – Feb 1 in Mesa (typical date) or Feb 14–28 (safer date). The soil should be at least 35°F.
When to plant sweet corn in Mesa
Tender crop. Sow sweet corn around the average last frost, per CSU: about Feb 1 in Mesa. Waiting until Feb 28 cuts the chance of a later 32°F night to 1 in 10. Seeds need soil of at least 50°F.
When to plant cucumbers in Mesa
Tender crop. Sow cucumbers around the average last frost, per CSU: about Feb 1 in Mesa. Waiting until Feb 28 cuts the chance of a later 32°F night to 1 in 10. Seeds need soil of at least 60°F. For fall, sow by Sep 18 (Aug 31 to be safe), which is 83 days before the first-frost date.
When to plant eggplant in Mesa
Very tender crop. CSU Extension's rule is 2+ weeks after the average last frost, which puts eggplant outside around Feb 15 (typical date), Feb 26 (balanced) or Mar 14 (safer 10% date). Start seeds indoors Dec 25 – Jan 15, 6–9 weeks ahead of transplanting on Feb 26. Set out on Feb 26, eggplant plants would start producing around Apr 27, based on CSU's typical 60 days from transplant to harvest. That leaves 227 days before the typical first frost (Dec 10).
When to plant cantaloupe in Mesa
Very tender crop. CSU Extension's rule is to plant cantaloupe at least 2 weeks after the average last frost. That's about Feb 15 using the typical date, Feb 26 as a balanced choice, or Mar 14 if you go by the safer 10% date. Seeds need soil of at least 60°F.
When to plant watermelon in Mesa
Very tender crop. CSU Extension's rule is to plant watermelon at least 2 weeks after the average last frost. That's about Feb 15 using the typical date, Feb 26 as a balanced choice, or Mar 14 if you go by the safer 10% date. Seeds need soil of at least 60°F.
When to plant winter squash in Mesa
Very tender crop. Following CSU Extension's rule of 2+ weeks after the average last frost, plant winter squash around Feb 15 at the earliest, Feb 26 as a balanced choice, or Mar 14 to be safe. CSU's minimum soil temperature is 60°F.
How these dates are calculated
| Rule | Applies to | Source (scope) |
|---|---|---|
| Hardy (cool season): “As early as 2-4 weeks before the date of the average last spring frost.” | Onions (dry, from sets), Peas, Lettuce (leaf), Broccoli, Cabbage, Kohlrabi, Green onions, Radishes, Spinach, Turnips | Colorado State University Extension, Vegetable Planting Guide (CMG GardenNotes #720) (written for Colorado; its frost-relative rules are applied to other states' NOAA frost dates and labelled as CSU (Colorado) rules) |
| Semi-hardy (cool season): “As early as 0-2 weeks before the date of the average last spring frost.” | Potatoes, Carrots, Cauliflower, Beets, Swiss chard, Parsnips | Colorado State University Extension, Vegetable Planting Guide (CMG GardenNotes #720) (written for Colorado; its frost-relative rules are applied to other states' NOAA frost dates and labelled as CSU (Colorado) rules) |
| Tender (warm season): “From seed: around the date of the average last spring frost” | Beans (snap), Summer squash, Sweet corn, Cucumbers | Colorado State University Extension, Vegetable Planting Guide (CMG GardenNotes #720) (written for Colorado; its frost-relative rules are applied to other states' NOAA frost dates and labelled as CSU (Colorado) rules) |
| Very tender (warm season): “Typically 2+ weeks after the average last spring frost date.” | Tomatoes, Peppers, Eggplant, Cantaloupe, Watermelon, Winter squash | Colorado State University Extension, Vegetable Planting Guide (CMG GardenNotes #720) (written for Colorado; its frost-relative rules are applied to other states' NOAA frost dates and labelled as CSU (Colorado) rules) |
| Start indoors = transplant age (weeks) before the balanced transplant date; days to harvest; minimum soil temperature | Crops with those values in CSU's table | CSU Extension, Vegetable Planting Guide (CMG GardenNotes #720) (written for Colorado; its frost-relative rules are applied to other states' NOAA frost dates and labelled as CSU (Colorado) rules) |
| Night-temperature dates: first day the NOAA 1991–2020 daily normal low (DLY-TMIN-NORMAL) is above the CSU transplant threshold or reaches the fruit-set threshold | Tomatoes (above 52°F at transplant, 55°F fruit set), peppers (55°F fruit set) | CSU Growing Tomatoes, CSU Peppers and Eggplants (written for Colorado; generic temperature thresholds applied nationwide with attribution) |
| Fall count-back: days to harvest + fall factor (14) + frost-tender factor (14) | Peas, Lettuce (leaf), Carrots, Beans (snap), Summer squash, Broccoli, Cabbage, Kohlrabi, Green onions, Radishes, Spinach, Turnips, Beets, Swiss chard, Cucumbers | UNL Extension, Fall Vegetable Gardening (G1343) (written for Nebraska; the count-back formula is applied nationwide with attribution) |
CSU states its spring rules relative to “the average last spring frost.” We use the 50% date as that average and also show the 30% and 10% anchors. See the methodology for details and limitations.
FAQ
When should I start seeds indoors in Mesa?
Tomatoes: Feb 22 – Mar 8. Peppers: Jan 1–15. Both windows count back from a balanced (30%-risk) transplant date using CSU's transplant ages.
When should I plant tomatoes outside in Mesa?
About Apr 12, at every risk level. CSU wants tomatoes out 2+ weeks after the average last frost (that rule alone gives about Feb 15 here) and nights above 52°F. At E Mesa, the average nightly low first rises above 52°F on Apr 12, later than the frost-rule date, so the night rule sets the date.
What can I plant in Mesa in the fall?
Counting back from the typical first frost (Dec 10) with UNL Extension's method: peas by Sep 22; lettuce (leaf) by Sep 27; carrots by Sep 17; beans (snap) by Sep 13; summer squash by Sep 23; broccoli by Sep 22 (transplants); cabbage by Sep 2 (transplants); kohlrabi by Oct 7; green onions by Sep 27; radishes by Oct 27; spinach by Oct 17; turnips by Oct 7; beets by Sep 27; swiss chard by Sep 27; cucumbers by Sep 18.