Storm Lake, IA planting zone & frost dates
Storm Lake is in USDA hardiness zone 5a. The last spring frost usually comes around April 25 and the first fall frost around October 13, for a growing season of about 170 days.
Planting calendar for Storm Lake
Dates are counted from the average last spring frost (April 25) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Feb 28 – Mar 14 Transplant outdoors: May 2 – May 9 |
| Peppers | Start seeds indoors: Feb 14 – Feb 28 Transplant outdoors: May 9 – May 16 |
| Eggplant | Start seeds indoors: Feb 14 – Feb 28 Transplant outdoors: May 9 – May 16 |
| Broccoli | Start seeds indoors: Feb 14 – Feb 28 Transplant outdoors: Mar 28 – Apr 11 |
| Cabbage | Start seeds indoors: Feb 14 – Feb 28 Transplant outdoors: Mar 28 – Apr 11 |
| Onions (sets) | Plant outdoors: Mar 28 – Apr 11 |
| Peas | Sow outdoors: Mar 14 – Mar 28 |
| Spinach | Sow outdoors: Mar 14 – Mar 28 |
| Lettuce | Sow outdoors: Mar 28 – Apr 11 |
| Carrots | Sow outdoors: Mar 28 – Apr 11 |
| Potatoes | Plant outdoors: Mar 28 – Apr 11 |
| Beans | Sow outdoors: May 2 – May 9 |
| Sweet corn | Sow outdoors: May 2 – May 9 |
| Cucumbers | Sow outdoors: May 2 – May 9 |
| Squash & zucchini | Sow outdoors: May 2 – May 9 |
| Basil | Start seeds indoors: Mar 14 – Mar 28 Transplant outdoors: May 2 – May 9 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 18 (8 weeks before the average first fall frost on Oct 13).
Useful for zone 5a gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
- Cold frame / mini greenhouse — adds weeks to a short season
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Apr 11 | Apr 25 | May 7 |
| First 32°F frost in fall is before | Oct 25 | Oct 13 | Oct 1 |
How to read it: in spring there is a 10% chance of a frost after May 7, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 1. A hard freeze (28°F) usually ends around April 15.
Hardiness zone by ZIP code in Storm Lake
- 50588 zone 5a
Nearby cities
- Spencer zone 5a, last frost May 1
- Fort Dodge zone 5a, last frost Apr 28
- Sioux City zone 5a, last frost Apr 29
- Boone zone 5a, last frost Apr 28
- Council Bluffs zone 6a, last frost Apr 18
- Waukee zone 5b, last frost Apr 19
- Ames zone 5b, last frost Apr 26
- Grimes zone 5b, last frost Apr 19
Questions
What growing zone is Storm Lake, IA?
Storm Lake is in USDA Plant Hardiness Zone 5a (average extreme winter low -20°F to -15°F), according to the USDA 2023 map.
When is the last frost in Storm Lake?
The average last spring frost (32°F) in Storm Lake is April 25. There is still a 10% chance of frost until May 7.
When can I plant tomatoes in Storm Lake?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 2 – May 9. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Storm Lake, IA (USC00137979), 1.5 km (0.9 mi) from the city center, elevation 440 m, based on 26 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.