Frost Dates for Willmar, MN 56201
Last spring frost May 2 · First fall frost September 30 · 151 frost-free days · USDA Zone 4b
ZIP 56201 has about 25,100 people.
Moderate season: 151 frost-free days. Spring frost risk spans April 17–May 17 (30 days). Fall frost risk spans September 17–October 14 (27 days).
Frost probability for 56201
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 17 | May 2 | April 17 |
| Fall (first frost) | September 17 | September 30 | October 14 |
Dates come from NOAA 1971–2000 freeze probabilities at NEW LONDON (24.0 km away); the 50% date is the median year.
Which crops fit a 151-day season in Willmar
In Willmar (151 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 28 | May 16–May 23 | 109 | fits: 80 days to maturity, 109 available after May 16. | May 31 |
| Pepper | Mar 21 | May 16–May 23 | 109 | fits: 75 days to maturity, 109 available after May 16. | Jun 5 |
| Lettuce | Mar 7 | Apr 4–Apr 11 | 186 | two-plantings: Plant Apr 4 and again by Aug 9; both mature before Oct 7. | Aug 9 |
| Carrots | — | Apr 11–Apr 18 | 193 | fits: 70 days to maturity, 193 available after Apr 11. | Jul 29 |
| Cucumber | Apr 11 | May 16–May 23 | 123 | fits: 60 days to maturity, 123 available after May 16. | Jul 4 |
| Beans | — | May 9–May 23 | 137 | two-plantings: Plant May 9 and again by Jul 11; both mature before Sep 23. | Jul 11 |
| Peas | — | Mar 7–May 16 | 214 | fits: 65 days to maturity, 214 available after Mar 7. | Jul 20 |
| Zucchini | Apr 18 | May 16–May 23 | 123 | fits: 55 days to maturity, 123 available after May 16. | Jul 9 |
| Onion | Feb 7 | Apr 4–Apr 18 | 186 | fits: 100 days to maturity, 186 available after Apr 4. | — |
| Spinach | — | Mar 7–Apr 25 | 228 | two-plantings: Plant Mar 7 and again by Aug 28; both mature before Oct 21. | Aug 28 |
| Kale | Feb 21 | Apr 4–Apr 18 | 200 | two-plantings: Plant Apr 4 and again by Aug 13; both mature before Oct 21. | Aug 13 |
| Broccoli | Mar 7 | Apr 4–Apr 18 | 186 | fits: 80 days to maturity, 186 available after Apr 4. | Jul 5 |
| Cabbage | Mar 7 | Apr 4–Apr 18 | 200 | fits: 70 days to maturity, 200 available after Apr 4. | Jul 29 |
| Radish | — | Mar 7–May 30 | 214 | two-plantings: Plant Mar 7 and again by Aug 29; both mature before Oct 7. | Aug 29 |
| Beets | — | Mar 7–May 30 | 214 | two-plantings: Plant Mar 7 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Potatoes | — | Apr 18–Apr 25 | 172 | fits: 90 days to maturity, 172 available after Apr 18. | — |
| Garlic | — | Sep 30 | 256 | overwinter: Plant Sep 30 to Oct 21; harvest the following summer. | Oct 21 |
| Strawberry | — | Mar 28–May 23 | 207 | perennial: A perennial: plant Mar 28; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 4 | May 9–May 16 | 123 | fits: 75 days to maturity, 123 available after May 9. | Jun 12 |
| Pumpkin | Apr 18 | May 16–May 16 | 116 | fits: 100 days to maturity, 116 available after May 16. | May 18 |
| Cauliflower | Mar 21 | Apr 25–May 9 | 165 | fits: 75 days to maturity, 165 available after Apr 25. | Jul 10 |
| Swiss Chard | Mar 7 | Apr 18–Apr 18 | 172 | two-plantings: Plant Apr 18 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Arugula | — | Mar 7–May 30 | 228 | two-plantings: Plant Mar 7 and again by Aug 28; both mature before Oct 21. | Aug 28 |
| Brussel Sprouts | Mar 7 | Apr 4–Apr 18 | 200 | fits: 100 days to maturity, 200 available after Apr 4. | Jun 29 |
| Butternut Squash | Apr 18 | May 16–May 23 | 116 | fits: 100 days to maturity, 116 available after May 16. | May 18 |
| Eggplant | Mar 14 | May 16–May 23 | 109 | fits: 70 days to maturity, 109 available after May 16. | Jun 10 |
| Okra | Apr 4 | May 9–May 16 | 130 | two-plantings: Plant May 9 and again by Jul 9; both mature before Sep 16. | Jul 9 |
| Basil | Mar 28 | May 23–May 23 | 116 | fits: 60 days to maturity, 116 available after May 23. | Jul 4 |
| Cilantro | — | Apr 4–Apr 25 | 186 | two-plantings: Plant Apr 4 and again by Aug 4; both mature before Oct 7. | Aug 4 |
| Parsley | Feb 21 | May 9–May 16 | 151 | fits: 70 days to maturity, 151 available after May 9. | Jul 15 |
| Celery | Feb 21 | May 9–May 23 | 151 | fits: 120 days to maturity, 151 available after May 9. | May 26 |
| Scallions | Feb 21 | Apr 4–Apr 18 | 200 | two-plantings: Plant Apr 4 and again by Aug 8; both mature before Oct 21. | Aug 8 |
| Turnip | — | Apr 4–Apr 18 | 200 | two-plantings: Plant Apr 4 and again by Aug 18; both mature before Oct 21. | Aug 18 |
| Kohlrabi | — | Mar 21–Apr 4 | 214 | two-plantings: Plant Mar 21 and again by Aug 13; both mature before Oct 21. | Aug 13 |
| Bok Choy | Apr 4 | Apr 25–May 2 | 165 | two-plantings: Plant Apr 25 and again by Aug 9; both mature before Oct 7. | Aug 9 |
| Collards | Feb 21 | Apr 4–Apr 18 | 200 | two-plantings: Plant Apr 4 and again by Aug 8; both mature before Oct 21. | Aug 8 |
| Cantaloupe | Apr 18 | May 16–May 23 | 109 | fits: 85 days to maturity, 109 available after May 16. | May 26 |
| Chives | Feb 7 | May 9–May 16 | 165 | fits: 90 days to maturity, 165 available after May 9. | — |
| Dill | — | Mar 7–May 30 | 214 | two-plantings: Plant Mar 7 and again by Jul 30; both mature before Oct 7. | Jul 30 |
| Oregano | Feb 21 | May 9–May 16 | 165 | fits: 80 days to maturity, 165 available after May 9. | — |
| Rosemary | Feb 7 | May 9–May 16 | 151 | fits: 80 days to maturity, 151 available after May 9. | — |
| Sage | Mar 7 | May 9–May 16 | 165 | fits: 75 days to maturity, 165 available after May 9. | — |
| Thyme | Feb 21 | May 9–May 16 | 165 | fits: 90 days to maturity, 165 available after May 9. | — |
| Calendula | Mar 21 | Apr 18–May 2 | 172 | two-plantings: Plant Apr 18 and again by Aug 4; both mature before Oct 7. | Aug 4 |
| Cosmos | Apr 4 | May 2–May 16 | 137 | two-plantings: Plant May 2 and again by Jul 4; both mature before Sep 16. | Jul 4 |
| Lavender | Feb 7 | May 2–May 16 | 172 | fits: 90 days to maturity, 172 available after May 2. | — |
| Marigolds | Mar 21 | May 2–May 9 | 137 | two-plantings: Plant May 2 and again by Jul 14; both mature before Sep 16. | Jul 14 |
| Melons | Apr 18 | May 16–May 23 | 109 | fits: 85 days to maturity, 109 available after May 16. | May 26 |
| Mint | — | May 2–May 16 | 172 | fits: 90 days to maturity, 172 available after May 2. | — |
| Nasturtiums | Apr 4 | May 2–May 9 | 137 | two-plantings: Plant May 2 and again by Jul 9; both mature before Sep 16. | Jul 9 |
| Pole Beans | — | May 9–May 23 | 130 | fits: 65 days to maturity, 130 available after May 9. | Jun 29 |
| Spaghetti Squash | Apr 18 | May 16–May 23 | 116 | fits: 90 days to maturity, 116 available after May 16. | May 28 |
| Sunflowers | — | May 2–May 16 | 137 | fits: 70 days to maturity, 137 available after May 2. | Jun 24 |
| Tomatillos | Mar 7 | May 9–May 16 | 116 | fits: 75 days to maturity, 116 available after May 9. | Jun 5 |
| Watermelon | Apr 18 | May 9–May 16 | 116 | fits: 80 days to maturity, 116 available after May 9. | May 31 |
| Yellow Squash | Apr 18 | May 16–May 23 | 123 | fits: 55 days to maturity, 123 available after May 16. | Jul 9 |
| Zinnias | Apr 4 | May 2–May 16 | 137 | two-plantings: Plant May 2 and again by Jul 4; both mature before Sep 16. | Jul 4 |
Month by month in Willmar
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 7), Lavender (Feb 7), Onion (Feb 7), Rosemary (Feb 7), Celery (Feb 21), Collards (Feb 21), +5 more. |
| March | Start indoors: Broccoli (Mar 7), Brussel Sprouts (Mar 7), Cabbage (Mar 7), Lettuce (Mar 7), Sage (Mar 7), Swiss Chard (Mar 7), +8 more. Direct sow from: Arugula (Mar 7), Beets (Mar 7), Dill (Mar 7), Peas (Mar 7), Radish (Mar 7), Spinach (Mar 7), +1 more. Plant: Strawberry (Mar 28). |
| April | Start indoors: Bok Choy (Apr 4), Corn (Apr 4), Cosmos (Apr 4), Nasturtiums (Apr 4), Okra (Apr 4), Zinnias (Apr 4), +9 more. Direct sow from: Cilantro (Apr 4), Turnip (Apr 4), Carrots (Apr 11), Potatoes (Apr 18). Transplant from: Broccoli (Apr 4), Brussel Sprouts (Apr 4), Cabbage (Apr 4), Collards (Apr 4), Kale (Apr 4), Lettuce (Apr 4), +6 more. |
| May | Direct sow from: Sunflowers (May 2), Beans (May 9), Pole Beans (May 9). Transplant from: Cosmos (May 2), Lavender (May 2), Marigolds (May 2), Mint (May 2), Nasturtiums (May 2), Zinnias (May 2), +23 more. Last frost around May 2. Last sowing dates: Butternut Squash (May 18), Pumpkin (May 18), Cantaloupe (May 26), Celery (May 26), Melons (May 26), Spaghetti Squash (May 28), +2 more. |
| June | Last sowing dates: Pepper (Jun 5), Tomatillos (Jun 5), Eggplant (Jun 10), Corn (Jun 12), Sunflowers (Jun 24), Brussel Sprouts (Jun 29), +1 more. |
| July | Last sowing dates: Basil (Jul 4), Cosmos (Jul 4), Cucumber (Jul 4), Zinnias (Jul 4), Broccoli (Jul 5), Nasturtiums (Jul 9), +13 more. |
| August | Last sowing dates: Calendula (Aug 4), Cilantro (Aug 4), Collards (Aug 8), Scallions (Aug 8), Bok Choy (Aug 9), Lettuce (Aug 9), +6 more. |
| September | Direct sow from: Garlic (Sep 30). First frost around September 30. |
| October | Last sowing dates: Garlic (Oct 21). |
| 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 Willmar, MN (ZIP 56201)?
The median last spring frost date for Willmar, MN (ZIP code 56201) is around May 2. 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 17; one in ten it runs past May 17.
What is the first fall frost date in Willmar, MN?
The median first fall frost date for Willmar, MN is around September 30. 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 17 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Willmar, MN?
The frost-free growing season in Willmar is about 151 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 Willmar (151 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 Willmar, MN?
Willmar, MN is in USDA hardiness zone 4b (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 Willmar, MN?
Start tomatoes indoors Mar 28 and plant out May 16 in Willmar. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Willmar?
Two: plant Apr 4 and again by Aug 9; both mature before Oct 7.
When do I plant garlic in Willmar?
Sep 30 to Oct 21; it overwinters and is ready the following summer.
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