Gardening in Bismarck, ND
Every ZIP code in this metro is USDA zone 4a. That is unusual — most metros span several zones — and it means the one number people usually look up is the same wherever you are here.
Your freeze dates
Those are the earliest and latest medians among the 13 stations serving this metro — not an average, and not one station standing in for the rest. Half of years freeze later than a station's own median.
The spread is the point. Even in a metro that is one hardiness zone throughout, its stations disagree about the last spring freeze. Hardiness zone and frost date measure different things — a zone is the average annual coldest night, a freeze date is when the season turns — and a place can be uniform in one and varied in the other. Use the tools below with your own ZIP rather than the ends of this range.
Your growing season
NOAA publishes a growing-season length for each station, and across the 13 stations serving Bismarck, ND it runs 123–142 days . That figure is published, not computed from the two freeze dates — subtracting one from the other gives the wrong answer wherever a season crosses New Year. Mean summer high (June–August) runs 77–83 °F , below the 90 °F point where cool-season crops reliably bolt.
When to start seeds in Bismarck, ND
Every spring job for 63 crop dates, counted from this metro's own last spring freeze. Each is a range across all 13 stations — the earliest and latest that job falls anywhere in the metro — because no one station speaks for the whole area.
| Crop | Job | When | Offset |
|---|---|---|---|
| Green Onions | Start indoors | March 15 – March 24 | 8 weeks before |
| Peppers | Start indoors | March 15 – March 24 | 8 weeks before |
| Broccoli | Start indoors | March 29 – April 7 | 6 weeks before |
| Cabbage | Start indoors | March 29 – April 7 | 6 weeks before |
| Collards | Start indoors | March 29 – April 7 | 6 weeks before |
| Kale | Start indoors | March 29 – April 7 | 6 weeks before |
| Leaf Lettuce | Start indoors | March 29 – April 7 | 6 weeks before |
| Peas | Direct sow | March 29 – April 7 | 6 weeks before |
| Spinach | Direct sow | March 29 – April 7 | 6 weeks before |
| Sweet Potato | Start indoors | March 29 – April 7 | 6 weeks before |
| Tomatoes | Start indoors | March 29 – April 7 | 6 weeks before |
| Bok Choy | Start indoors | April 5 – April 14 | 5 weeks before |
| Kohlrabi | Start indoors | April 5 – April 14 | 5 weeks before |
| Swiss Chard | Start indoors | April 5 – April 14 | 5 weeks before |
| Arugula | Direct sow | April 12 – April 21 | 4 weeks before |
| Baby Salad Greens | Direct sow | April 12 – April 21 | 4 weeks before |
| Beets | Direct sow | April 12 – April 21 | 4 weeks before |
| Green Onions | Direct sow | April 12 – April 21 | 4 weeks before |
| Mustard Greens | Direct sow | April 12 – April 21 | 4 weeks before |
| Okra | Start indoors | April 12 – April 21 | 4 weeks before |
| Radishes | Direct sow | April 12 – April 21 | 4 weeks before |
| Turnips | Direct sow | April 12 – April 21 | 4 weeks before |
| Cabbage | Set out | April 19 – April 28 | 3 weeks before |
| Carrots | Direct sow | April 19 – April 28 | 3 weeks before |
| Collards | Direct sow | April 19 – April 28 | 3 weeks before |
| Collards | Set out | April 19 – April 28 | 3 weeks before |
| Cucumbers | Start indoors | April 19 – April 28 | 3 weeks before |
| Green Onions | Set out | April 19 – April 28 | 3 weeks before |
| Kale | Direct sow | April 19 – April 28 | 3 weeks before |
| Kale | Set out | April 19 – April 28 | 3 weeks before |
| Kohlrabi | Direct sow | April 19 – April 28 | 3 weeks before |
| Kohlrabi | Set out | April 19 – April 28 | 3 weeks before |
| Leaf Lettuce | Direct sow | April 19 – April 28 | 3 weeks before |
| Pumpkins | Start indoors | April 19 – April 28 | 3 weeks before |
| Summer Squash | Start indoors | April 19 – April 28 | 3 weeks before |
| Winter Squash | Start indoors | April 19 – April 28 | 3 weeks before |
| Zucchini | Start indoors | April 19 – April 28 | 3 weeks before |
| Bok Choy | Direct sow | April 26 – May 5 | 2 weeks before |
| Bok Choy | Set out | April 26 – May 5 | 2 weeks before |
| Broccoli | Set out | April 26 – May 5 | 2 weeks before |
| Cilantro | Direct sow | April 26 – May 5 | 2 weeks before |
| Leaf Lettuce | Set out | April 26 – May 5 | 2 weeks before |
| Swiss Chard | Direct sow | April 26 – May 5 | 2 weeks before |
| Swiss Chard | Set out | April 26 – May 5 | 2 weeks before |
| Dill | Direct sow | May 3 – May 12 | 1 week before |
| Bush Beans | Direct sow | May 17 – May 26 | 1 week after |
| Cucumbers | Set out | May 17 – May 26 | 1 week after |
| Pumpkins | Direct sow | May 17 – May 26 | 1 week after |
| Pumpkins | Set out | May 17 – May 26 | 1 week after |
| Summer Squash | Direct sow | May 17 – May 26 | 1 week after |
| Summer Squash | Set out | May 17 – May 26 | 1 week after |
| Sweet Corn | Direct sow | May 17 – May 26 | 1 week after |
| Tomatoes | Set out | May 17 – May 26 | 1 week after |
| Winter Squash | Direct sow | May 17 – May 26 | 1 week after |
| Winter Squash | Set out | May 17 – May 26 | 1 week after |
| Zucchini | Direct sow | May 17 – May 26 | 1 week after |
| Zucchini | Set out | May 17 – May 26 | 1 week after |
| Cucumbers | Direct sow | May 24 – June 2 | 2 weeks after |
| Okra | Direct sow | May 24 – June 2 | 2 weeks after |
| Okra | Set out | May 24 – June 2 | 2 weeks after |
| Peppers | Set out | May 24 – June 2 | 2 weeks after |
| Southern Peas | Direct sow | May 24 – June 2 | 2 weeks after |
| Sweet Potato | Set out | May 24 – June 2 | 2 weeks after |
The week offsets are conventional extension guidance and vary by variety; the freeze dates they are counted from are measured. For a single date rather than a range, run when do I start my seeds? with your own ZIP code.
What lives through a zone 4a winter
Winter hardiness runs on the zone alone, so this one is exact for the whole of Bismarck, ND rather than a range. Of 74 perennial fruits, nuts, berries, vegetables and herbs, 34 come through a zone 4a winter .
Among them: Cranberry, Honeyberry, Lingonberry, Apple, Aronia, Black Currant, Elderberry, Gooseberry. See the full list with reasons.
The 13 stations behind these numbers
Every figure above comes from these, and each is named so you can check it. Distances vary by ZIP code, so the tools report yours rather than this page guessing.
| Station | NOAA ID | Last spring freeze | First fall freeze | Season |
|---|---|---|---|---|
| Almont, ND | USC00320127 | May 17 | September 21 | 124 days |
| Bismarck 2.4 Nnw, ND | USC00320817 | May 10 | September 30 | 142 days |
| Bismarck Wfo, ND | USC00320818 | May 14 | September 30 | 138 days |
| Breien, ND | USC00321052 | May 12 | September 24 | 134 days |
| Center 4Se, ND | USC00321456 | May 11 | September 29 | 140 days |
| Flasher, ND | USC00323004 | May 13 | September 27 | 135 days |
| Hebron, ND | USC00324102 | May 19 | September 21 | 123 days |
| Mandan Exp Stn, ND | USC00325479 | May 13 | September 27 | 136 days |
| Moffit 3 SE, ND | USC00326015 | May 11 | September 29 | 139 days |
| New Salem 5Nw, ND | USC00326365 | May 18 | September 24 | 127 days |
| Steele 4N, ND | USC00328366 | May 15 | September 25 | 133 days |
| Tuttle 12Nne, ND | USC00328853 | May 13 | September 29 | 139 days |
| Wilton, ND | USC00329455 | May 11 | September 30 | 142 days |
These are medians, not averages — NOAA publishes freeze dates as a probability distribution, and half of years freeze later than the date shown.
Work out your own dates
Each of these takes a ZIP code and answers for that ZIP alone, citing the station it used and how far away it is. There is a ZIP box in the header of every page.
- What survives my winter?
Runs on the hardiness zone, so it answers for all of Bismarck, ND at once — zone 4a across 74 perennial fruits, berries, vegetables and herbs.
- When do I start my seeds?
Dates every spring job from your own last freeze — sow indoors, set out, direct sow.
- When do I sow the next round?
How often each crop is worth re-sowing, and when the next sowing is due.
- What can I still plant?
Counts the growing days left before your first fall freeze, crop by crop.
Where these numbers come from
The hardiness zone is the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. The freeze dates are NOAA's 1991–2020 Climate Normals, read from every station whose normals cover a ZIP code in this metro. Nothing here is estimated, and no station stands in for another.
This page names no single station on purpose. Picking one to represent a metro sounds reasonable and is not: the station serving the most ZIP codes is an artifact of where ZIP centroids happen to fall, and it selects a lock on the Monongahela for Pittsburgh and a far southern suburb for Chicago. A range across every station is true; a single cited date for a whole metro is not.