Zone 3 Planting Guide: When to Plant Vegetables in USDA Zone 3
USDA hardiness zone 3 (3a and 3b) covers places where the coldest winter night averages -40 to -30°F. This guide times seed-starting, transplanting, and fall planting for a typical zone 3 last frost of May 17 and first fall frost of Sep 23. Use transplants, black plastic mulch, and row covers; choose short-season varieties (≤70 days).
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 3 frost dates
| Earliest 10% of ZIPs | Typical (median) | Latest 10% of ZIPs | |
|---|---|---|---|
| Last spring frost (32°F) | May 12 | May 17 | May 30 |
| First fall frost (32°F) | Sep 7 | Sep 23 | Oct 1 |
Frost dates: medians of the nearest NOAA NCEI 1991–2020 Climate Normals station (32°F, 50% probability) for each ZIP code in zone 3 (223 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 3
| Month | What to plant (typical zone 3 timing) |
|---|---|
| March | Start indoors: broccoli, cabbage, eggplant, kale, peppers, tomatoes |
| April | Direct sow: lettuce, peas, radishes, spinach Start indoors: basil, marigolds, zinnias 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, lettuce, spinach |
| August | Fall sow: radishes Fall plant bulbs: daffodils |
| September | Fall plant bulbs: tulips Fall plant cloves: garlic |
Zone 3 planting calendar (23 crops)
Dates assume the typical zone 3 frost dates above; shift them with your own. Timing relative to frost:
| Plant | Task | Typical window |
|---|---|---|
| Basil | Start indoors | Apr 5 – Apr 19 |
| Basil | Transplant | May 24 – May 31 |
| Beans | Direct sow | May 24 – May 31 |
| Broccoli | Start indoors | Mar 8 – Mar 22 |
| Broccoli | Transplant | Apr 19 – May 3 |
| Broccoli | Fall transplant | Jul 1 – Jul 15 |
| Cabbage | Start indoors | Mar 8 – Mar 22 |
| Cabbage | Transplant | Apr 19 – May 3 |
| Cabbage | Fall transplant | Jul 1 – Jul 15 |
| Cucumbers | Direct sow | May 24 – May 31 |
| Daffodils | Fall plant bulbs | Aug 26 – Oct 7 |
| Eggplant | Start indoors | Mar 8 – Mar 22 |
| Eggplant | Transplant | May 31 – Jun 7 |
| Garlic | Fall plant cloves | Sep 23 – Oct 21 |
| Kale | Start indoors | Mar 8 – Mar 22 |
| Kale | Transplant | Apr 19 – May 3 |
| Kale | Fall sow | Jul 15 – Jul 29 |
| Lettuce | Direct sow | Apr 19 – May 3 |
| Lettuce | Fall sow | Jul 29 – Aug 12 |
| Marigolds | Start indoors | Apr 5 – Apr 19 |
| Marigolds | Direct sow / transplant | May 17 – May 24 |
| Onions | Plant sets/transplants | Apr 19 – May 3 |
| Peas | Direct sow | Apr 5 – Apr 19 |
| Peppers | Start indoors | Mar 8 – Mar 22 |
| Peppers | Transplant | May 31 – Jun 7 |
| Potatoes | Plant seed potatoes | Apr 19 – May 3 |
| Pumpkins | Direct sow | May 24 – Jun 7 |
| Radishes | Direct sow | Apr 12 – May 3 |
| Radishes | Fall sow | Aug 12 – Aug 26 |
| Spinach | Direct sow | Apr 5 – Apr 19 |
| Spinach | Fall sow | Jul 29 – Aug 12 |
| Squash | Direct sow | May 24 – May 31 |
| Sweet corn | Direct sow | May 24 – May 31 |
| Tomatoes | Start indoors | Mar 22 – Apr 5 |
| Tomatoes | Transplant | May 24 – May 31 |
| Tulips | Fall plant bulbs | Sep 9 – Oct 21 |
| Zinnias | Start indoors | Apr 5 – Apr 19 |
| Zinnias | Direct sow / transplant | May 17 – May 31 |
Cool-season vs warm-season crops in zone 3
- 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 3 areas
Alaska · Minnesota · North Dakota
Frequently asked questions
When is the last frost in zone 3?
Across ZIP codes in USDA zone 3, the median last spring frost (32°F) at the nearest NOAA station is about May 17, with most falling between May 12 and May 30. Hardiness zones measure winter lows, not frost dates, so look up your ZIP for a local date.
What are zone 3 winter temperatures?
USDA zone 3 means an average annual extreme minimum temperature of -40 to -30°F (1991–2020), split into 3a (colder half) and 3b.
When should I plant tomatoes in zone 3?
Transplant tomatoes about 1–2 weeks after your last frost (typical zone 3: around May 24), once nights stay above 50°F. Start seeds indoors 6–8 weeks before the last frost.
Which states are in zone 3?
Large parts of Alaska, Minnesota, North Dakota fall in zone 3 on the 2023 USDA map. Check your ZIP code, since zones vary within states.
Other zone guides
Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9 · Zone 10 · Zone 11 · Zone map · Frost dates