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Flagstaff, AZ Planting Calendar

The last spring frost in Flagstaff usually comes around May 30 and the first fall frost around Oct 2, a growing season of about 125 days. Start tomatoes indoors Apr 18 – May 2 and plant them outside Jun 13 – Jun 27.

Last spring frostMay 30
First fall frostOct 2
Growing season125 days

When to plant vegetables in Flagstaff

VegetableStart seeds indoorsPlant outsideFall crop
TomatoesApr 18 – May 2Jun 13 – Jun 27—
PeppersApr 11 – Apr 25Jun 20 – Jul 4—
EggplantApr 11 – Apr 25Jun 20 – Jul 4—
Cucumbers—Jun 13 – Jun 27—
Zucchini & summer squash—Jun 13 – Jun 27—
Pumpkins & winter squash—Jun 20 – Jul 4—
Green beans—Jun 13 – Jun 27Jul 10 – Jul 24
Sweet corn—Jun 13 – Jun 27—
BasilMay 2 – May 16Jun 13 – Jun 27—
LettuceApr 4 – Apr 18May 2 – Jun 13Aug 7 – Aug 21
Spinach—Apr 18 – May 9Aug 7 – Aug 21
Peas—Apr 18 – May 9Jul 24 – Aug 7
Carrots—May 2 – Jun 6Jul 10 – Jul 24
Radishes—Apr 25 – Jun 13Aug 21 – Sep 4
BroccoliMar 21 – Apr 4May 2 – May 16Jul 10 – Jul 24
KaleApr 4 – Apr 18Apr 25 – May 9Jul 24 – Aug 7
Onions—May 2 – May 16—
Potatoes—May 9 – Jun 6—
Garlic——Sep 18 – Oct 23

Dates count from the median frost dates (2016–2025) for Flagstaff. In a cold spring, wait a week; in a warm one you can go a week early.

Month-by-month planting in Flagstaff

  1. JanuaryPlan, order seeds and prepare beds.
  2. FebruaryPlan, order seeds and prepare beds.
  3. MarchStart indoors: Broccoli
  4. AprilStart indoors: Tomatoes, Peppers, Eggplant, Lettuce, Broccoli, KalePlant outside: Spinach, Peas, Radishes, Kale
  5. MayStart indoors: Tomatoes, BasilPlant outside: Lettuce, Spinach, Peas, Carrots, Radishes, Broccoli, Kale, Onions, Potatoes
  6. JunePlant outside: Tomatoes, Peppers, Eggplant, Cucumbers, Zucchini & summer squash, Pumpkins & winter squash, Green beans, Sweet corn, Basil, Lettuce, Carrots, Radishes, Potatoes
  7. JulyPlant outside: Peppers, Eggplant, Pumpkins & winter squash, Green beans, Peas, Carrots, Broccoli, Kale
  8. AugustPlant outside: Lettuce, Spinach, Peas, Radishes, Kale
  9. SeptemberPlant outside: Radishes, Garlic
  10. OctoberPlant outside: Garlic
  11. NovemberPlan, order seeds and prepare beds.
  12. DecemberPlan, order seeds and prepare beds.

Tools for this season

Seed starting kitTrays with humidity domes for starting seeds indoors.See options on AmazonLED grow lightKeeps indoor seedlings short and sturdy.See options on AmazonFrost clothCovers tender plants on a surprise frost night.See options on AmazonSoil thermometerCheck the soil at 4 inches before you spread anything.See options on Amazon

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Frequently asked questions

When is the last frost in Flagstaff?

The median last spring frost is May 30 and the median first fall frost is Oct 2, based on 2016–2025 weather data.

When should I plant tomatoes in Flagstaff?

Start seeds indoors Apr 18 – May 2 and set plants outside Jun 13 – Jun 27, once nights stay above 50°F.

When should I plant a fall garden in Flagstaff?

Sow or transplant cool-season crops 6 to 12 weeks before the first fall frost (around Oct 2): broccoli and carrots first, lettuce, spinach and radishes last.

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