LawnWeather

Casper, WY Planting Calendar

The last spring frost in Casper usually comes around May 11 and the first fall frost around Oct 5, a growing season of about 147 days. Start tomatoes indoors Mar 30 – Apr 13 and plant them outside May 25 – Jun 8.

Last spring frostMay 11
First fall frostOct 5
Growing season147 days

When to plant vegetables in Casper

VegetableStart seeds indoorsPlant outsideFall crop
TomatoesMar 30 – Apr 13May 25 – Jun 8—
PeppersMar 23 – Apr 6Jun 1 – Jun 15—
EggplantMar 23 – Apr 6Jun 1 – Jun 15—
Cucumbers—May 25 – Jun 8—
Zucchini & summer squash—May 25 – Jun 8—
Pumpkins & winter squash—Jun 1 – Jun 15—
Green beans—May 25 – Jun 8Jul 13 – Jul 27
Sweet corn—May 25 – Jun 8—
BasilApr 13 – Apr 27May 25 – Jun 8—
LettuceMar 16 – Mar 30Apr 13 – May 25Aug 10 – Aug 24
Spinach—Mar 30 – Apr 20Aug 10 – Aug 24
Peas—Mar 30 – Apr 20Jul 27 – Aug 10
Carrots—Apr 13 – May 18Jul 13 – Jul 27
Radishes—Apr 6 – May 25Aug 24 – Sep 7
BroccoliMar 2 – Mar 16Apr 13 – Apr 27Jul 13 – Jul 27
KaleMar 16 – Mar 30Apr 6 – Apr 20Jul 27 – Aug 10
Onions—Apr 13 – Apr 27—
Potatoes—Apr 20 – May 18—
Garlic——Sep 21 – Oct 26

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

Month-by-month planting in Casper

  1. JanuaryPlan, order seeds and prepare beds.
  2. FebruaryPlan, order seeds and prepare beds.
  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, Cucumbers, Zucchini & summer 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 Casper?

The median last spring frost is May 11 and the median first fall frost is Oct 5, based on 2016–2025 weather data.

When should I plant tomatoes in Casper?

Start seeds indoors Mar 30 – Apr 13 and set plants outside May 25 – Jun 8, once nights stay above 50°F.

When should I plant a fall garden in Casper?

Sow or transplant cool-season crops 6 to 12 weeks before the first fall frost (around Oct 5): broccoli and carrots first, lettuce, spinach and radishes last.

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