Frost Dates for Le Mars, IA 51031
Last spring frost May 1 · First fall frost September 28 · 150 frost-free days · USDA Zone 5a
ZIP 51031 has about 12,800 people.
Moderate season: 150 frost-free days. Spring frost risk spans April 18–May 14 (26 days). Fall frost risk spans September 16–October 11 (25 days).
Frost probability for 51031
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 14 | May 1 | April 18 |
| Fall (first frost) | September 16 | September 28 | October 11 |
Dates come from NOAA 1971–2000 freeze probabilities at SIOUX CTR 2 SE (28.2 km away); the 50% date is the median year.
Which crops fit a 150-day season in Le Mars
In Le Mars (150 frost-free days, a moderate season), 34 of 56 planner crops fit outright, 21 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 27 | May 15–May 22 | 108 | fits: 80 days to maturity, 108 available after May 15. | May 29 |
| Pepper | Mar 20 | May 15–May 22 | 108 | fits: 75 days to maturity, 108 available after May 15. | Jun 3 |
| Lettuce | Mar 6 | Apr 3–Apr 10 | 185 | two-plantings: Plant Apr 3 and again by Aug 7; both mature before Oct 5. | Aug 7 |
| Carrots | — | Apr 10–Apr 17 | 192 | fits: 70 days to maturity, 192 available after Apr 10. | Jul 27 |
| Cucumber | Apr 10 | May 15–May 22 | 122 | fits: 60 days to maturity, 122 available after May 15. | Jul 2 |
| Beans | — | May 8–May 22 | 136 | two-plantings: Plant May 8 and again by Jul 9; both mature before Sep 21. | Jul 9 |
| Peas | — | Mar 6–May 15 | 213 | fits: 65 days to maturity, 213 available after Mar 6. | Jul 18 |
| Zucchini | Apr 17 | May 15–May 22 | 122 | fits: 55 days to maturity, 122 available after May 15. | Jul 7 |
| Onion | Feb 6 | Apr 3–Apr 17 | 185 | fits: 100 days to maturity, 185 available after Apr 3. | — |
| Spinach | — | Mar 6–Apr 24 | 227 | two-plantings: Plant Mar 6 and again by Aug 26; both mature before Oct 19. | Aug 26 |
| Kale | Feb 20 | Apr 3–Apr 17 | 199 | two-plantings: Plant Apr 3 and again by Aug 11; both mature before Oct 19. | Aug 11 |
| Broccoli | Mar 6 | Apr 3–Apr 17 | 185 | fits: 80 days to maturity, 185 available after Apr 3. | Jul 3 |
| Cabbage | Mar 6 | Apr 3–Apr 17 | 199 | fits: 70 days to maturity, 199 available after Apr 3. | Jul 27 |
| Radish | — | Mar 6–May 29 | 213 | two-plantings: Plant Mar 6 and again by Aug 27; both mature before Oct 5. | Aug 27 |
| Beets | — | Mar 6–May 29 | 213 | two-plantings: Plant Mar 6 and again by Jul 28; both mature before Oct 5. | Jul 28 |
| Potatoes | — | Apr 17–Apr 24 | 171 | fits: 90 days to maturity, 171 available after Apr 17. | — |
| Garlic | — | Sep 28 | 255 | overwinter: Plant Sep 28 to Oct 19; harvest the following summer. | Oct 19 |
| Strawberry | — | Mar 27–May 22 | 206 | perennial: A perennial: plant Mar 27; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 3 | May 8–May 15 | 122 | fits: 75 days to maturity, 122 available after May 8. | Jun 10 |
| Pumpkin | Apr 17 | May 15–May 15 | 115 | fits: 100 days to maturity, 115 available after May 15. | May 16 |
| Cauliflower | Mar 20 | Apr 24–May 8 | 164 | fits: 75 days to maturity, 164 available after Apr 24. | Jul 8 |
| Swiss Chard | Mar 6 | Apr 17–Apr 17 | 171 | two-plantings: Plant Apr 17 and again by Jul 28; both mature before Oct 5. | Jul 28 |
| Arugula | — | Mar 6–May 29 | 227 | two-plantings: Plant Mar 6 and again by Aug 26; both mature before Oct 19. | Aug 26 |
| Brussel Sprouts | Mar 6 | Apr 3–Apr 17 | 199 | fits: 100 days to maturity, 199 available after Apr 3. | Jun 27 |
| Butternut Squash | Apr 17 | May 15–May 22 | 115 | fits: 100 days to maturity, 115 available after May 15. | May 16 |
| Eggplant | Mar 13 | May 15–May 22 | 108 | fits: 70 days to maturity, 108 available after May 15. | Jun 8 |
| Okra | Apr 3 | May 8–May 15 | 129 | two-plantings: Plant May 8 and again by Jul 7; both mature before Sep 14. | Jul 7 |
| Basil | Mar 27 | May 22–May 22 | 115 | fits: 60 days to maturity, 115 available after May 22. | Jul 2 |
| Cilantro | — | Apr 3–Apr 24 | 185 | two-plantings: Plant Apr 3 and again by Aug 2; both mature before Oct 5. | Aug 2 |
| Parsley | Feb 20 | May 8–May 15 | 150 | fits: 70 days to maturity, 150 available after May 8. | Jul 13 |
| Celery | Feb 20 | May 8–May 22 | 150 | fits: 120 days to maturity, 150 available after May 8. | May 24 |
| Scallions | Feb 20 | Apr 3–Apr 17 | 199 | two-plantings: Plant Apr 3 and again by Aug 6; both mature before Oct 19. | Aug 6 |
| Turnip | — | Apr 3–Apr 17 | 199 | two-plantings: Plant Apr 3 and again by Aug 16; both mature before Oct 19. | Aug 16 |
| Kohlrabi | — | Mar 20–Apr 3 | 213 | two-plantings: Plant Mar 20 and again by Aug 11; both mature before Oct 19. | Aug 11 |
| Bok Choy | Apr 3 | Apr 24–May 1 | 164 | two-plantings: Plant Apr 24 and again by Aug 7; both mature before Oct 5. | Aug 7 |
| Collards | Feb 20 | Apr 3–Apr 17 | 199 | two-plantings: Plant Apr 3 and again by Aug 6; both mature before Oct 19. | Aug 6 |
| Cantaloupe | Apr 17 | May 15–May 22 | 108 | fits: 85 days to maturity, 108 available after May 15. | May 24 |
| Chives | Feb 6 | May 8–May 15 | 164 | fits: 90 days to maturity, 164 available after May 8. | — |
| Dill | — | Mar 6–May 29 | 213 | two-plantings: Plant Mar 6 and again by Jul 28; both mature before Oct 5. | Jul 28 |
| Oregano | Feb 20 | May 8–May 15 | 164 | fits: 80 days to maturity, 164 available after May 8. | — |
| Rosemary | Feb 6 | May 8–May 15 | 150 | fits: 80 days to maturity, 150 available after May 8. | — |
| Sage | Mar 6 | May 8–May 15 | 164 | fits: 75 days to maturity, 164 available after May 8. | — |
| Thyme | Feb 20 | May 8–May 15 | 164 | fits: 90 days to maturity, 164 available after May 8. | — |
| Calendula | Mar 20 | Apr 17–May 1 | 171 | two-plantings: Plant Apr 17 and again by Aug 2; both mature before Oct 5. | Aug 2 |
| Cosmos | Apr 3 | May 1–May 15 | 136 | two-plantings: Plant May 1 and again by Jul 2; both mature before Sep 14. | Jul 2 |
| Lavender | Feb 6 | May 1–May 15 | 171 | fits: 90 days to maturity, 171 available after May 1. | — |
| Marigolds | Mar 20 | May 1–May 8 | 136 | two-plantings: Plant May 1 and again by Jul 12; both mature before Sep 14. | Jul 12 |
| Melons | Apr 17 | May 15–May 22 | 108 | fits: 85 days to maturity, 108 available after May 15. | May 24 |
| Mint | — | May 1–May 15 | 171 | fits: 90 days to maturity, 171 available after May 1. | — |
| Nasturtiums | Apr 3 | May 1–May 8 | 136 | two-plantings: Plant May 1 and again by Jul 7; both mature before Sep 14. | Jul 7 |
| Pole Beans | — | May 8–May 22 | 129 | fits: 65 days to maturity, 129 available after May 8. | Jun 27 |
| Spaghetti Squash | Apr 17 | May 15–May 22 | 115 | fits: 90 days to maturity, 115 available after May 15. | May 26 |
| Sunflowers | — | May 1–May 15 | 136 | fits: 70 days to maturity, 136 available after May 1. | Jun 22 |
| Tomatillos | Mar 6 | May 8–May 15 | 115 | fits: 75 days to maturity, 115 available after May 8. | Jun 3 |
| Watermelon | Apr 17 | May 8–May 15 | 115 | fits: 80 days to maturity, 115 available after May 8. | May 29 |
| Yellow Squash | Apr 17 | May 15–May 22 | 122 | fits: 55 days to maturity, 122 available after May 15. | Jul 7 |
| Zinnias | Apr 3 | May 1–May 15 | 136 | two-plantings: Plant May 1 and again by Jul 2; both mature before Sep 14. | Jul 2 |
Month by month in Le Mars
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 6), Lavender (Feb 6), Onion (Feb 6), Rosemary (Feb 6), Celery (Feb 20), Collards (Feb 20), +5 more. |
| March | Start indoors: Broccoli (Mar 6), Brussel Sprouts (Mar 6), Cabbage (Mar 6), Lettuce (Mar 6), Sage (Mar 6), Swiss Chard (Mar 6), +8 more. Direct sow from: Arugula (Mar 6), Beets (Mar 6), Dill (Mar 6), Peas (Mar 6), Radish (Mar 6), Spinach (Mar 6), +1 more. Plant: Strawberry (Mar 27). |
| April | Start indoors: Bok Choy (Apr 3), Corn (Apr 3), Cosmos (Apr 3), Nasturtiums (Apr 3), Okra (Apr 3), Zinnias (Apr 3), +9 more. Direct sow from: Cilantro (Apr 3), Turnip (Apr 3), Carrots (Apr 10), Potatoes (Apr 17). Transplant from: Broccoli (Apr 3), Brussel Sprouts (Apr 3), Cabbage (Apr 3), Collards (Apr 3), Kale (Apr 3), Lettuce (Apr 3), +6 more. |
| May | Direct sow from: Sunflowers (May 1), Beans (May 8), Pole Beans (May 8). Transplant from: Cosmos (May 1), Lavender (May 1), Marigolds (May 1), Mint (May 1), Nasturtiums (May 1), Zinnias (May 1), +23 more. Last frost around May 1. Last sowing dates: Butternut Squash (May 16), Pumpkin (May 16), Cantaloupe (May 24), Celery (May 24), Melons (May 24), Spaghetti Squash (May 26), +2 more. |
| June | Last sowing dates: Pepper (Jun 3), Tomatillos (Jun 3), Eggplant (Jun 8), Corn (Jun 10), Sunflowers (Jun 22), Brussel Sprouts (Jun 27), +1 more. |
| July | Last sowing dates: Basil (Jul 2), Cosmos (Jul 2), Cucumber (Jul 2), Zinnias (Jul 2), Broccoli (Jul 3), Nasturtiums (Jul 7), +13 more. |
| August | Last sowing dates: Calendula (Aug 2), Cilantro (Aug 2), Collards (Aug 6), Scallions (Aug 6), Bok Choy (Aug 7), Lettuce (Aug 7), +6 more. |
| September | Direct sow from: Garlic (Sep 28). First frost around September 28. |
| October | Last sowing dates: Garlic (Oct 19). |
| November | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
| December | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
Frequently Asked Questions
What is the last frost date for Le Mars, IA (ZIP 51031)?
The median last spring frost date for Le Mars, IA (ZIP code 51031) is around May 1. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area. One year in ten frost ends before April 18; one in ten it runs past May 14.
What is the first fall frost date in Le Mars, IA?
The median first fall frost date for Le Mars, IA is around September 28. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around September 16 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Le Mars, IA?
The frost-free growing season in Le Mars is about 150 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Le Mars (150 frost-free days, a moderate season), 34 of 56 planner crops fit outright, 21 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Le Mars, IA?
Le Mars, IA is in USDA hardiness zone 5a (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.
When should I start tomatoes indoors in Le Mars, IA?
Start tomatoes indoors Mar 27 and plant out May 15 in Le Mars. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Le Mars?
Two: plant Apr 3 and again by Aug 7; both mature before Oct 5.
When do I plant garlic in Le Mars?
Sep 28 to Oct 19; it overwinters and is ready the following summer.
Which nearby ZIP has a longer season?
Storm Lake (ZIP 50588) has 158 frost-free days, 8 more than Le Mars (ZIP 51031). See Storm Lake ZIP 50588 frost dates
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