Frost Dates for Bismarck, ND 58505
Last spring frost May 13 · First fall frost September 23 · 133 frost-free days · USDA Zone 4a
ZIP 58505 has about 22 people, one of 4 ZIP codes in Bismarck.
Moderate season: 133 frost-free days. Spring frost risk spans May 1–May 26 (25 days). Fall frost risk spans September 11–October 4 (23 days).
Frost probability for 58505
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 26 | May 13 | May 1 |
| Fall (first frost) | September 11 | September 23 | October 4 |
Dates come from NOAA 1971–2000 freeze probabilities at MANDAN EXP STN (9.8 km away); the 50% date is the median year.
Which crops fit a 133-day season in Bismarck
In Bismarck (133 frost-free days, a moderate season), 37 of 56 planner crops fit outright, 16 get two plantings, 2 need an indoor start, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Apr 8 | May 27–Jun 3 | 91 | fits: 80 days to maturity, 91 available after May 27. | — |
| Pepper | Apr 1 | May 27–Jun 3 | 91 | fits: 75 days to maturity, 91 available after May 27. | May 29 |
| Lettuce | Mar 18 | Apr 15–Apr 22 | 168 | two-plantings: Plant Apr 15 and again by Aug 2; both mature before Sep 30. | Aug 2 |
| Carrots | — | Apr 22–Apr 29 | 175 | fits: 70 days to maturity, 175 available after Apr 22. | Jul 22 |
| Cucumber | Apr 22 | May 27–Jun 3 | 105 | fits: 60 days to maturity, 105 available after May 27. | Jun 27 |
| Beans | — | May 20–Jun 3 | 119 | fits: 60 days to maturity, 119 available after May 20. | Jul 4 |
| Peas | — | Mar 18–May 27 | 196 | fits: 65 days to maturity, 196 available after Mar 18. | Jul 13 |
| Zucchini | Apr 29 | May 27–Jun 3 | 105 | fits: 55 days to maturity, 105 available after May 27. | Jul 2 |
| Onion | Feb 18 | Apr 15–Apr 29 | 168 | fits: 100 days to maturity, 168 available after Apr 15. | — |
| Spinach | — | Mar 18–May 6 | 210 | two-plantings: Plant Mar 18 and again by Aug 21; both mature before Oct 14. | Aug 21 |
| Kale | Mar 4 | Apr 15–Apr 29 | 182 | two-plantings: Plant Apr 15 and again by Aug 6; both mature before Oct 14. | Aug 6 |
| Broccoli | Mar 18 | Apr 15–Apr 29 | 168 | fits: 80 days to maturity, 168 available after Apr 15. | Jun 28 |
| Cabbage | Mar 18 | Apr 15–Apr 29 | 182 | fits: 70 days to maturity, 182 available after Apr 15. | Jul 22 |
| Radish | — | Mar 18–Jun 10 | 196 | two-plantings: Plant Mar 18 and again by Aug 22; both mature before Sep 30. | Aug 22 |
| Beets | — | Mar 18–Jun 10 | 196 | two-plantings: Plant Mar 18 and again by Jul 23; both mature before Sep 30. | Jul 23 |
| Potatoes | — | Apr 29–May 6 | 154 | fits: 90 days to maturity, 154 available after Apr 29. | — |
| Garlic | — | Sep 23 | 238 | overwinter: Plant Sep 23 to Oct 14; harvest the following summer. | Oct 14 |
| Strawberry | — | Apr 8–Jun 3 | 189 | perennial: A perennial: plant Apr 8; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 15 | May 20–May 27 | 105 | fits: 75 days to maturity, 105 available after May 20. | Jun 5 |
| Pumpkin | Apr 29 | May 27–May 27 | 98 | head-start: Even planted out May 27, the outdoor season is about 2 days short; choose an early variety or grow under cover. | — |
| Cauliflower | Apr 1 | May 6–May 20 | 147 | fits: 75 days to maturity, 147 available after May 6. | Jul 3 |
| Swiss Chard | Mar 18 | Apr 29–Apr 29 | 154 | two-plantings: Plant Apr 29 and again by Jul 23; both mature before Sep 30. | Jul 23 |
| Arugula | — | Mar 18–Jun 10 | 210 | two-plantings: Plant Mar 18 and again by Aug 21; both mature before Oct 14. | Aug 21 |
| Brussel Sprouts | Mar 18 | Apr 15–Apr 29 | 182 | fits: 100 days to maturity, 182 available after Apr 15. | Jun 22 |
| Butternut Squash | Apr 29 | May 27–Jun 3 | 98 | head-start: Even planted out May 27, the outdoor season is about 2 days short; choose an early variety or grow under cover. | — |
| Eggplant | Mar 25 | May 27–Jun 3 | 91 | fits: 70 days to maturity, 91 available after May 27. | Jun 3 |
| Okra | Apr 15 | May 20–May 27 | 112 | fits: 55 days to maturity, 112 available after May 20. | Jul 2 |
| Basil | Apr 8 | Jun 3–Jun 3 | 98 | fits: 60 days to maturity, 98 available after Jun 3. | Jun 27 |
| Cilantro | — | Apr 15–May 6 | 168 | two-plantings: Plant Apr 15 and again by Jul 28; both mature before Sep 30. | Jul 28 |
| Parsley | Mar 4 | May 20–May 27 | 133 | fits: 70 days to maturity, 133 available after May 20. | Jul 8 |
| Celery | Mar 4 | May 20–Jun 3 | 133 | fits: 120 days to maturity, 133 available after May 20. | — |
| Scallions | Mar 4 | Apr 15–Apr 29 | 182 | two-plantings: Plant Apr 15 and again by Aug 1; both mature before Oct 14. | Aug 1 |
| Turnip | — | Apr 15–Apr 29 | 182 | two-plantings: Plant Apr 15 and again by Aug 11; both mature before Oct 14. | Aug 11 |
| Kohlrabi | — | Apr 1–Apr 15 | 196 | two-plantings: Plant Apr 1 and again by Aug 6; both mature before Oct 14. | Aug 6 |
| Bok Choy | Apr 15 | May 6–May 13 | 147 | two-plantings: Plant May 6 and again by Aug 2; both mature before Sep 30. | Aug 2 |
| Collards | Mar 4 | Apr 15–Apr 29 | 182 | two-plantings: Plant Apr 15 and again by Aug 1; both mature before Oct 14. | Aug 1 |
| Cantaloupe | Apr 29 | May 27–Jun 3 | 91 | fits: 85 days to maturity, 91 available after May 27. | — |
| Chives | Feb 18 | May 20–May 27 | 147 | fits: 90 days to maturity, 147 available after May 20. | — |
| Dill | — | Mar 18–Jun 10 | 196 | two-plantings: Plant Mar 18 and again by Jul 23; both mature before Sep 30. | Jul 23 |
| Oregano | Mar 4 | May 20–May 27 | 147 | fits: 80 days to maturity, 147 available after May 20. | — |
| Rosemary | Feb 18 | May 20–May 27 | 133 | fits: 80 days to maturity, 133 available after May 20. | — |
| Sage | Mar 18 | May 20–May 27 | 147 | fits: 75 days to maturity, 147 available after May 20. | — |
| Thyme | Mar 4 | May 20–May 27 | 147 | fits: 90 days to maturity, 147 available after May 20. | — |
| Calendula | Apr 1 | Apr 29–May 13 | 154 | two-plantings: Plant Apr 29 and again by Jul 28; both mature before Sep 30. | Jul 28 |
| Cosmos | Apr 15 | May 13–May 27 | 119 | fits: 60 days to maturity, 119 available after May 13. | Jun 27 |
| Lavender | Feb 18 | May 13–May 27 | 154 | fits: 90 days to maturity, 154 available after May 13. | — |
| Marigolds | Apr 1 | May 13–May 20 | 119 | two-plantings: Plant May 13 and again by Jul 7; both mature before Sep 9. | Jul 7 |
| Melons | Apr 29 | May 27–Jun 3 | 91 | fits: 85 days to maturity, 91 available after May 27. | — |
| Mint | — | May 13–May 27 | 154 | fits: 90 days to maturity, 154 available after May 13. | — |
| Nasturtiums | Apr 15 | May 13–May 20 | 119 | fits: 55 days to maturity, 119 available after May 13. | Jul 2 |
| Pole Beans | — | May 20–Jun 3 | 112 | fits: 65 days to maturity, 112 available after May 20. | Jun 22 |
| Spaghetti Squash | Apr 29 | May 27–Jun 3 | 98 | fits: 90 days to maturity, 98 available after May 27. | — |
| Sunflowers | — | May 13–May 27 | 119 | fits: 70 days to maturity, 119 available after May 13. | Jun 17 |
| Tomatillos | Mar 18 | May 20–May 27 | 98 | fits: 75 days to maturity, 98 available after May 20. | May 29 |
| Watermelon | Apr 29 | May 20–May 27 | 98 | fits: 80 days to maturity, 98 available after May 20. | May 24 |
| Yellow Squash | Apr 29 | May 27–Jun 3 | 105 | fits: 55 days to maturity, 105 available after May 27. | Jul 2 |
| Zinnias | Apr 15 | May 13–May 27 | 119 | fits: 60 days to maturity, 119 available after May 13. | Jun 27 |
Month by month in Bismarck
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 18), Lavender (Feb 18), Onion (Feb 18), Rosemary (Feb 18). |
| March | Start indoors: Celery (Mar 4), Collards (Mar 4), Kale (Mar 4), Oregano (Mar 4), Parsley (Mar 4), Scallions (Mar 4), +9 more. Direct sow from: Arugula (Mar 18), Beets (Mar 18), Dill (Mar 18), Peas (Mar 18), Radish (Mar 18), Spinach (Mar 18). |
| April | Start indoors: Calendula (Apr 1), Cauliflower (Apr 1), Marigolds (Apr 1), Pepper (Apr 1), Basil (Apr 8), Tomato (Apr 8), +15 more. Direct sow from: Kohlrabi (Apr 1), Cilantro (Apr 15), Turnip (Apr 15), Carrots (Apr 22), Potatoes (Apr 29). Transplant from: Broccoli (Apr 15), Brussel Sprouts (Apr 15), Cabbage (Apr 15), Collards (Apr 15), Kale (Apr 15), Lettuce (Apr 15), +4 more. Plant: Strawberry (Apr 8). |
| May | Direct sow from: Sunflowers (May 13), Beans (May 20), Pole Beans (May 20). Transplant from: Bok Choy (May 6), Cauliflower (May 6), Cosmos (May 13), Lavender (May 13), Marigolds (May 13), Mint (May 13), +24 more. Last frost around May 13. Last sowing dates: Watermelon (May 24), Pepper (May 29), Tomatillos (May 29). |
| June | Transplant from: Basil (Jun 3). Last sowing dates: Eggplant (Jun 3), Corn (Jun 5), Sunflowers (Jun 17), Brussel Sprouts (Jun 22), Pole Beans (Jun 22), Basil (Jun 27), +4 more. |
| July | Last sowing dates: Nasturtiums (Jul 2), Okra (Jul 2), Yellow Squash (Jul 2), Zucchini (Jul 2), Cauliflower (Jul 3), Beans (Jul 4), +10 more. |
| August | Last sowing dates: Collards (Aug 1), Scallions (Aug 1), Bok Choy (Aug 2), Lettuce (Aug 2), Kale (Aug 6), Kohlrabi (Aug 6), +4 more. |
| September | Direct sow from: Garlic (Sep 23). First frost around September 23. |
| October | Last sowing dates: Garlic (Oct 14). |
| 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 Bismarck, ND (ZIP 58505)?
The median last spring frost date for Bismarck, ND (ZIP code 58505) is around May 13. 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 May 1; one in ten it runs past May 26.
What is the first fall frost date in Bismarck, ND?
The median first fall frost date for Bismarck, ND is around September 23. 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 11 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Bismarck, ND?
The frost-free growing season in Bismarck is about 133 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 Bismarck (133 frost-free days, a moderate season), 37 of 56 planner crops fit outright, 16 get two plantings, 2 need an indoor start, 1 crop is perennial.
What USDA hardiness zone is Bismarck, ND?
Bismarck, ND is in USDA hardiness zone 4a (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 Bismarck, ND?
Start tomatoes indoors Apr 8 and plant out May 27 in Bismarck. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Bismarck?
Two: plant Apr 15 and again by Aug 2; both mature before Sep 30.
When do I plant garlic in Bismarck?
Sep 23 to Oct 14; it overwinters and is ready the following summer.
Can I grow Butternut Squash in Bismarck?
Yes, with help. Even planted out May 27, the outdoor season is about 2 days short; choose an early variety or grow under cover.
Nearby and related
- Frost dates for Bismarck, ND 58503 (6.1 mi)
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