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Great Falls, MT Planting Calendar

The last spring frost in Great Falls usually comes around May 6 and the first fall frost around Oct 9, a growing season of about 156 days. Start tomatoes indoors Mar 25 – Apr 8 and plant them outside May 20 – Jun 3.

Last spring frostMay 6
First fall frostOct 9
Growing season156 days

When to plant vegetables in Great Falls

VegetableStart seeds indoorsPlant outsideFall crop
TomatoesMar 25 – Apr 8May 20 – Jun 3—
PeppersMar 18 – Apr 1May 27 – Jun 10—
EggplantMar 18 – Apr 1May 27 – Jun 10—
Cucumbers—May 20 – Jun 3—
Zucchini & summer squash—May 20 – Jun 3—
Pumpkins & winter squash—May 27 – Jun 10—
Green beans—May 20 – Jun 3Jul 17 – Jul 31
Sweet corn—May 20 – Jun 3—
BasilApr 8 – Apr 22May 20 – Jun 3—
LettuceMar 11 – Mar 25Apr 8 – May 20Aug 14 – Aug 28
Spinach—Mar 25 – Apr 15Aug 14 – Aug 28
Peas—Mar 25 – Apr 15Jul 31 – Aug 14
Carrots—Apr 8 – May 13Jul 17 – Jul 31
Radishes—Apr 1 – May 20Aug 28 – Sep 11
BroccoliFeb 25 – Mar 11Apr 8 – Apr 22Jul 17 – Jul 31
KaleMar 11 – Mar 25Apr 1 – Apr 15Jul 31 – Aug 14
Onions—Apr 8 – Apr 22—
Potatoes—Apr 15 – May 13—
Garlic——Sep 25 – Oct 30

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

Month-by-month planting in Great Falls

  1. JanuaryPlan, order seeds and prepare beds.
  2. FebruaryStart indoors: Broccoli
  3. MarchStart indoors: Tomatoes, Peppers, Eggplant, Lettuce, Broccoli, KalePlant outside: Spinach, Peas
  4. AprilStart indoors: Tomatoes, Peppers, Eggplant, BasilPlant outside: Lettuce, Spinach, Peas, Carrots, Radishes, Broccoli, Kale, Onions, Potatoes
  5. MayPlant outside: Tomatoes, Peppers, Eggplant, Cucumbers, Zucchini & summer squash, Pumpkins & winter squash, Green beans, Sweet corn, Basil, Lettuce, Carrots, Radishes, Potatoes
  6. JunePlant outside: Tomatoes, Peppers, Eggplant, Cucumbers, Zucchini & summer squash, Pumpkins & winter squash, Green beans, Sweet corn, Basil
  7. JulyPlant outside: 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 Great Falls?

The median last spring frost is May 6 and the median first fall frost is Oct 9, based on 2016–2025 weather data.

When should I plant tomatoes in Great Falls?

Start seeds indoors Mar 25 – Apr 8 and set plants outside May 20 – Jun 3, once nights stay above 50°F.

When should I plant a fall garden in Great Falls?

Sow or transplant cool-season crops 6 to 12 weeks before the first fall frost (around Oct 9): broccoli and carrots first, lettuce, spinach and radishes last.

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