Zone 4 Planting Guide: When to Plant Vegetables in USDA Zone 4
USDA hardiness zone 4 (4a and 4b) covers places where the coldest winter night averages -30 to -20°F. This guide times seed-starting, transplanting, and fall planting for a typical zone 4 last frost of May 10 and first fall frost of Sep 30. Pick short-season varieties and warm soil with plastic mulch before planting tomatoes and peppers.
About these dates: Timings are counted from your average last spring frost date, which is only an average — a frost can still occur after it. Dates vary within a state by elevation, distance from water, and microclimate. Look up the frost date for your ZIP code (your state Cooperative Extension office or NOAA climate normals are good sources) and adjust for the current season’s weather and soil temperature.
Zone 4 frost dates
| Earliest 10% of ZIPs | Typical (median) | Latest 10% of ZIPs | |
|---|---|---|---|
| Last spring frost (32°F) | May 2 | May 10 | May 26 |
| First fall frost (32°F) | Sep 19 | Sep 30 | Oct 7 |
Frost dates: medians of the nearest NOAA NCEI 1991–2020 Climate Normals station (32°F, 50% probability) for each ZIP code in zone 4 (1,950 ZIPs). Zones: USDA 2023 Plant Hardiness Zone Map ZIP data, PRISM Climate Group (Oregon State University); this is a summary, not the official USDA map. Your local dates can differ by weeks — use the ZIP planner or frost-date tables.
What to plant each month in zone 4
| Month | What to plant (typical zone 4 timing) |
|---|---|
| March | Start indoors: basil, broccoli, cabbage, eggplant, kale, marigolds, peppers, tomatoes, zinnias Direct sow: peas, spinach |
| April | Direct sow: lettuce, radishes Plant sets/transplants: onions Plant seed potatoes: potatoes Transplant: broccoli, cabbage, kale |
| May | Direct sow / transplant: marigolds, zinnias Transplant: basil, eggplant, peppers, tomatoes Direct sow: beans, cucumbers, pumpkins, squash, sweet corn |
| July | Fall transplant: broccoli, cabbage Fall sow: kale |
| August | Fall sow: lettuce, radishes, spinach |
| September | Fall plant bulbs: daffodils, tulips Fall plant cloves: garlic |
Zone 4 planting calendar (23 crops)
Dates assume the typical zone 4 frost dates above; shift them with your own. Timing relative to frost:
| Plant | Task | Typical window |
|---|---|---|
| Basil | Start indoors | Mar 29 – Apr 12 |
| Basil | Transplant | May 17 – May 24 |
| Beans | Direct sow | May 17 – May 24 |
| Broccoli | Start indoors | Mar 1 – Mar 15 |
| Broccoli | Transplant | Apr 12 – Apr 26 |
| Broccoli | Fall transplant | Jul 8 – Jul 22 |
| Cabbage | Start indoors | Mar 1 – Mar 15 |
| Cabbage | Transplant | Apr 12 – Apr 26 |
| Cabbage | Fall transplant | Jul 8 – Jul 22 |
| Cucumbers | Direct sow | May 17 – May 24 |
| Daffodils | Fall plant bulbs | Sep 2 – Oct 14 |
| Eggplant | Start indoors | Mar 1 – Mar 15 |
| Eggplant | Transplant | May 24 – May 31 |
| Garlic | Fall plant cloves | Sep 30 – Oct 28 |
| Kale | Start indoors | Mar 1 – Mar 15 |
| Kale | Transplant | Apr 12 – Apr 26 |
| Kale | Fall sow | Jul 22 – Aug 5 |
| Lettuce | Direct sow | Apr 12 – Apr 26 |
| Lettuce | Fall sow | Aug 5 – Aug 19 |
| Marigolds | Start indoors | Mar 29 – Apr 12 |
| Marigolds | Direct sow / transplant | May 10 – May 17 |
| Onions | Plant sets/transplants | Apr 12 – Apr 26 |
| Peas | Direct sow | Mar 29 – Apr 12 |
| Peppers | Start indoors | Mar 1 – Mar 15 |
| Peppers | Transplant | May 24 – May 31 |
| Potatoes | Plant seed potatoes | Apr 12 – Apr 26 |
| Pumpkins | Direct sow | May 17 – May 31 |
| Radishes | Direct sow | Apr 5 – Apr 26 |
| Radishes | Fall sow | Aug 19 – Sep 2 |
| Spinach | Direct sow | Mar 29 – Apr 12 |
| Spinach | Fall sow | Aug 5 – Aug 19 |
| Squash | Direct sow | May 17 – May 24 |
| Sweet corn | Direct sow | May 17 – May 24 |
| Tomatoes | Start indoors | Mar 15 – Mar 29 |
| Tomatoes | Transplant | May 17 – May 24 |
| Tulips | Fall plant bulbs | Sep 16 – Oct 28 |
| Zinnias | Start indoors | Mar 29 – Apr 12 |
| Zinnias | Direct sow / transplant | May 10 – May 24 |
Cool-season vs warm-season crops in zone 4
- Cool-season (peas, spinach, lettuce, radishes, kale, onions, potatoes, broccoli, cabbage, garlic): tolerate light frost; plant in early spring and again late summer–fall.
- Warm-season (tomatoes, peppers, eggplant, beans, sweet corn, cucumbers, squash, pumpkins, basil, marigolds, zinnias): frost-tender; plant after the last frost once soil warms.
States with large zone 4 areas
North Dakota · Minnesota · South Dakota · Montana · Wisconsin · Wyoming · Vermont · Alaska · Maine
Frequently asked questions
When is the last frost in zone 4?
Across ZIP codes in USDA zone 4, the median last spring frost (32°F) at the nearest NOAA station is about May 10, with most falling between May 2 and May 26. Hardiness zones measure winter lows, not frost dates, so look up your ZIP for a local date.
What are zone 4 winter temperatures?
USDA zone 4 means an average annual extreme minimum temperature of -30 to -20°F (1991–2020), split into 4a (colder half) and 4b.
When should I plant tomatoes in zone 4?
Transplant tomatoes about 1–2 weeks after your last frost (typical zone 4: around May 17), once nights stay above 50°F. Start seeds indoors 6–8 weeks before the last frost.
Which states are in zone 4?
Large parts of North Dakota, Minnesota, South Dakota, Montana, Wisconsin, Wyoming, Vermont, Alaska fall in zone 4 on the 2023 USDA map. Check your ZIP code, since zones vary within states.
Other zone guides
Zone 3 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9 · Zone 10 · Zone 11 · Zone map · Frost dates