Des Moines, IA Frost Dates & Growing Season

The two dates every Des Moines garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
Apr 18
~50% chance of frost after
First fall frost
Oct 20
~50% chance of frost before
Growing season
185 days
frost-free stretch
USDA zone
5b
2023 hardiness map
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Apr 4 Apr 18 May 2
First fall frost Nov 1 Oct 20 Oct 4
Hard freeze (28°F), median last Apr 8 · first Oct 30

Computed from NOAA 1991–2020 climate normals at the Des Moines International Airport station (7 km from central Des Moines). "Safe" means frost past that date happens only about one year in ten. Your exact garden can still run days either way with elevation and terrain — check your own ZIP with the frost date lookup.

Planting windows for Des Moines

Computed from Des Moines's own frost dates. Click any crop for the full zone-5 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Feb 21 – Mar 7 Apr 25 – May 2
🫑 Peppers Feb 7 – Feb 21 May 2 – May 9
🥬 Lettuce Mar 7 – Mar 21 Mar 21 – Apr 4 Mar 21 – Apr 18
🫛 Peas Mar 7 – Mar 21
🥕 Carrots Mar 28 – Apr 18
🥦 Broccoli Feb 28 – Mar 14 Mar 28 – Apr 11
🥬 Kale Mar 7 – Mar 21 Mar 21 – Apr 4 Mar 21 – Apr 4
🥒 Cucumbers Mar 21 – Mar 28 Apr 25 – May 2 Apr 25 – May 2
🥒 Zucchini Mar 21 – Mar 28 Apr 25 – May 2 Apr 25 – May 2
🫘 Green Beans (Bush) Apr 25 – May 2
🌽 Sweet Corn Apr 25 – May 2
🌿 Basil Mar 7 – Mar 21 Apr 25 – May 2 May 2 – May 9
🧄 Garlic Fall: Sep 8 – Oct 6

Want this for all 50 crops, or as a printable seed-shelf schedule? Use the planting calendar and the seed starting scheduler — both can use Des Moines's dates automatically after a lookup.

Reading the season in Des Moines

Roughly 185 frost-free days gives Des Moines gardeners room for nearly every common vegetable. Warm-season crops go out after Apr 18; a fall garden sown in late summer matures comfortably before the Oct 20 frost.

Frequently asked questions

When is the last frost in Des Moines, IA?

The average last spring frost in Des Moines is around Apr 18, based on 1991–2020 climate normals. That's a median — about half of years see a later frost, so tender crops are safest going out a week or two after this date.

When is the first frost in Des Moines, IA?

The average first fall frost in Des Moines arrives around Oct 20. Crops still in the garden need to mature before then, and frost-tender plants need harvesting or protection as the date approaches.

How long is the growing season in Des Moines?

About 185 frost-free days on average, from Apr 18 to Oct 20. That fits nearly all common vegetables, though the longest-season melons and sweet potatoes benefit from transplants.

What USDA zone is Des Moines in?

USDA zone 5b on the 2023 Plant Hardiness Zone Map. Note that zones describe winter cold, not frost timing — these frost dates are the numbers to plan plantings around.