USDA hardiness zone lookup
Bismarck (South) (58504) — USDA Zone 4a
Bismarck (South), North Dakota · 129-day growing season
Frost dates and growing season for 58504
| USDA hardiness zone | Zone 4a |
|---|---|
| Average last spring frost | May 14 |
| Average first fall frost | September 20 |
| Growing season length | ~129 days |
| Temperature range (F) | -30 to -20°F |
| Temperature range (C) | -34 to -29°C |
These are 50%-probability averages modeled from this ZIP's USDA hardiness zone and regional climate normals — not a single-station reading. In a typical year the last spring frost will have passed by May 14, but in a colder-than-average year it can run 1-2 weeks later. Plant tender crops (tomatoes, peppers, basil) once both soil and night temperatures are consistently warm — a thermometer beats the calendar.
Growing season in Bismarck (South)
Bismarck (South), North Dakota sits in USDA Zone 4a, with roughly 129 frost-free days between an average last spring frost around May 14 and a first fall frost around September 20. That is a standard temperate season — most common vegetables finish comfortably, and a single main planting plus one succession round works well.
What grows in Bismarck (South)
Bismarck (South) falls in USDA Zone 4a, which means the same hardiness constraints apply as the full Zone 4 guide. Vegetables, herbs, and fruit trees rated to Zone 4a (or hardier) will overwinter here in a typical year.
- Apple, pear, plum, sour cherry
- Blueberries (highbush)
- Raspberries
- Strawberries
- Tomatoes
- Peppers (short-season)
- Cucumbers
- Beans
- Squash (summer + winter)
- Garlic
What to plant in Bismarck (South) this week
Bismarck (South)'s last frost is around May 14. This is the spring transplant window — start tomatoes and peppers indoors if you haven't, and direct-sow cold-tolerant crops now.
- When to plant tomatoes in zone 4
- When to plant peppers in zone 4
- When to plant basil in zone 4
- When to plant bush beans in zone 4
- When to plant cucumbers in zone 4
Full planting calendar for Bismarck (South)
Crop-by-crop sowing, transplant, and harvest dates calibrated to zone 4 averages:
- When to plant tomatoes in zone 4
- When to plant peppers in zone 4
- When to plant basil in zone 4
- When to plant garlic in zone 4
- When to plant lettuce in zone 4
- When to plant bush beans in zone 4
- When to plant cucumbers in zone 4
- When to plant summer squash in zone 4
- When to plant peas in zone 4
- When to plant carrots in zone 4
Local microclimate notes
Zone tables give you the average — but Bismarck (South)gardens vary. South-facing walls and paved areas can run a full half-zone warmer than the published rating. Low-lying spots, frost pockets, and shaded north sides can run colder. If you've gardened here a few seasons, your own frost record (the last time you actually got frost damage) is more accurate than any national average.
Source and methodology
Hardiness zone from the USDA Plant Hardiness Zone Map (2023 revision). Frost-date and growing-season figures are modeled from this ZIP's USDA hardiness zone and regional NOAA 1991-2020 climate normals — they are zone-level estimates, not a per-station record, so treat them as planning guidance and confirm against your own local frost history. Crop recommendations are drawn from US Cooperative Extension references and curated by the Growli editorial team. Last reviewed May 2026.
Nearby ZIP codes in North Dakota
- 58501 — Bismarck (Zone 4a)
- 58102 — Fargo (Zone 4a)
- 58103 — Fargo (South) (Zone 4a)
- 58104 — Fargo (Southwest) (Zone 4a)
- 58201 — Grand Forks (Zone 3b)
- 58701 — Minot (Zone 4a)
- Browse all US ZIP codes by state