Brought to you by garden.gg Zone 4a Planting Calendar & Schedule
Zone 4 is a cold continental climate with long, freezing winters (annual minimum temperatures of -30 to -20 F) and a short, often variable growing season of about four months. Hard frosts persist into late spring and return by mid-September, making variety selection and season extension essential.
Zone 4a is the cooler half of USDA zone 4, where the average coldest winter night bottoms out at −30 to −25°F. Compared with the zone 4 averages, the last spring frost in zone 4a comes about a week later (Jun 1) and the first fall frost about a week earlier (Sep 8), for a growing season of about 99 days. Every planting window on this page is shifted to match: spring sowing and transplant dates move a week later, fall plantings a week earlier. Crop notes still quote zone 4 timing.
Zone 4 spans much of Montana and North Dakota, northern Minnesota and Wisconsin, Upper Michigan, the Adirondacks, and the mountain valleys of Vermont and New Hampshire, with winter lows of -30 to -20°F. Its 113-day season is the first that reliably ripens main-season tomatoes and peppers from transplants. Winter squash and melons still need the shortest-season varieties available, started indoors in early May.
States & regions in Zone 4: Northern Minnesota, Northern Wisconsin, Northern Maine, Upper Michigan, Montana (much of the state), North Dakota, Northern New York / Adirondacks, Vermont & New Hampshire mountains, Wyoming valleys, Northern Iowa
The sweet spot of northern gardening.
Zone 4 gives you just enough season to grow the classics — tomatoes, peppers, corn — but you need to be strategic. Start indoors early, harden off carefully, and know exactly when your last frost hits. No room for winging it.
Pro tip: Succession plant lettuce and radishes every 2 weeks from April through August. You'll never run out of salad greens.
Save a planting for your zone 4a garden — free
What to Plant in Zone 4a This Fall (September–November)
The average first fall frost in zone 4a is Sep 8. To find the last safe planting date for any fall crop, count back from that date by its days to maturity plus a 14-day fall factor — growth slows as days shorten and soil cools. Applied to zone 4a's frost date, that gives these plant-by dates:
Plant by Jul 26
30 days to maturity + 14-day fall factor
Plant by Jul 11
45 days to maturity + 14-day fall factor
Plant by Jul 6
50 days to maturity + 14-day fall factor
Plant by Jul 1
55 days to maturity + 14-day fall factor
Zone 4a and 4b: these dates count back from zone 4a's first frost, which is about a week earlier than the zone 4 average of Sep 15. Zone 4b gardeners have about two weeks more fall time — see the zone 4b fall dates.
Fall crops on this zone 4a calendar include Spinach, Lettuce, Arugula, Radish, Mustard Greens, Mizuna, Tatsoi, Bok Choy / Pak Choi, Napa Cabbage, Kale, Turnip, Rutabaga, and 4 more. Each crop's sowing and transplant window is in the fall planting section below.
For month-by-month detail, see what to plant in October across every zone, what to plant in September, and the fall vegetable planting guide by zone.
What to Plant by Season in Zone 4a
The right crops and methods for each season, based on zone 4a's climate and frost timing.
What to Plant in Spring
Spring is short and the soil is slow to warm. The real work begins indoors in late winter under lights, with cold-hardy greens and roots direct-sown outdoors as soon as soil is workable in April-early May, well ahead of the late-May last frost.
Mar 28 - May 7
Start 6-8 weeks before last frost; do not transplant out until after May 25.
Mar 18 - May 7
Slow to start; sow 8-10 weeks before last frost with bottom heat.
Mar 18 - May 7
Needs warmth and a long start; choose short-season varieties.
Mar 28 - May 7
Start with tomatoes; plant at least two for pollination.
Mar 28 - May 7
Slow germinator; start 8 weeks early.
Feb 28 - Apr 7
Long-day types for the north; start 10-12 weeks early or use sets in May.
Feb 28 - Apr 7
Very long season; start early indoors.
Mar 8 - May 7
Slow; needs steady warmth and moisture to germinate.
Mar 8 - May 7
Long season; start 10 weeks before transplanting.
Mar 28 - May 7
Transplant out mid-May; tolerates light frost.
Mar 28 - May 7
Start indoors for an early summer crop.
Mar 28 - May 7
Hardy transplant; can set out before last frost.
Mar 28 - May 7
Long season; start early to mature before hard fall freezes.
Apr 8 - May 7
Can also be direct-sown in early May.
Apr 8 - May 7
Prone to bolting; a fall crop is often more reliable.
Apr 18 - May 17
Very cold tolerant; trellis tall types.
Apr 18 - May 17
Direct sow early; declines in summer heat.
Apr 18 - May 17
Very frost hardy; plant as soon as soil thaws.
Apr 18 - Jun 7
Direct sow early; bolts in heat.
Apr 18 - Jun 7
Succession sow every 2 weeks; tolerates light frost.
Apr 18 - Jun 7
Fast and cold-tolerant.
Apr 18 - Jun 7
Quick cool-season green.
Apr 18 - Jun 7
Quick crop; ready in 25-30 days.
Apr 28 - Jun 7
Sow once soil reaches 45 F; keep evenly moist.
Apr 28 - Jun 7
Tolerates frost; thin seedlings.
Apr 8 - Jun 7
Fast cool-season root.
Apr 8 - Jun 7
Slow germinator; needs the full season, sweetens after frost.
Apr 28 - Jun 7
Plant seed potatoes ~2 weeks before last frost; hill as they grow.
Apr 28 - Jun 7
Plant sets in early spring for summer harvest.
Apr 8 - Jun 7
Very hardy; flavor improves with frost.
Apr 28 - Jun 7
Heat and cold tolerant; long harvest.
Apr 8 - Jun 7
Hardy brassica green; tolerates frost.
Apr 8 - Jun 7
Bolts in heat; succession sow.
Apr 8 - Jun 7
Direct sow; self-seeds readily.
Mar 8 - May 7
Slow to germinate; soak seed first.
Apr 8 - Jun 7
Hardy perennial; returns each spring.
Apr 28 - Jun 7
Plant crowns; perennial bed, no harvest year one.
Apr 8 - Jun 7
Plant crowns; cold-loving perennial ideal for zone 4.
Apr 8 - Jun 7
Set out bare-root crowns; mulch for winter survival.
Apr 8 - Jun 7
Cold-tolerant; direct sow early.
Apr 8 - Jun 7
Loves cool weather; sow as soon as soil is workable.
Mar 8 - May 7
Frost tolerant; start early for long bloom.
Apr 8 - Jun 7
Hardy perennial green.
Apr 8 - Jun 7
Extremely cold hardy salad green.
What to Plant in Summer
Summer is the brief warm window (June-August) when frost-tender crops finally go in the ground. After the May 25 last frost, transplant heat-lovers and direct-sow warm-season crops quickly, since first frost returns by mid-September.
May 28 - Jun 17
Harden off; protect from any late frost with row cover.
Jun 8 - Jun 17
Wait for warm soil and settled nights above 50 F.
Jun 8 - Jun 17
Needs the warmest spot; black plastic mulch helps.
May 28 - Jun 17
Vigorous; give cages and space.
May 28 - Jun 17
Sprawling; harvest fallen husks when papery.
Jun 8 - Jun 27
Direct sow in warm soil or transplant; trellis to save space.
Jun 8 - Jun 27
Direct sow after frost; very productive.
Jun 8 - Jun 27
Harvest young and often.
Jun 8 - Jun 17
Choose short-season varieties; needs full season to cure.
Jun 8 - Jun 17
Pick early-maturing types for zone 4 (90-100 days).
Jun 8 - Jun 17
Compact pie types fit the short season well.
Jun 8 - Jun 27
Use transplants and black plastic; choose 70-75 day varieties.
Jun 8 - Jun 27
Only short-season icebox types reliably ripen; use transplants.
May 28 - Jun 17
Sow in blocks for pollination; choose early varieties.
Jun 8 - Jun 27
Direct sow in warm soil; succession sow for steady harvest.
Jun 8 - Jun 27
Trellis; longer harvest than bush types.
Jun 8 - Jun 27
Choose early varieties for a single harvest.
Jun 8 - Jun 27
Tolerates cool nights better than common beans; ornamental too.
Jun 8 - Jun 27
Very frost-sensitive; wait until nights are warm.
Jun 8 - Jun 17
Warm-season annual herb.
Jun 8 - Jun 17
Heat-loving green; sow in warm soil.
May 28 - Jul 7
Direct sow; choose shorter-season varieties for seed heads.
May 28 - Jul 7
Edible flowers; thrives in poor soil.
May 28 - Jul 7
Plant after frost; deters some pests.
May 28 - Jul 7
Heat-loving cut flower; sow after frost.
May 28 - Jul 7
Easy from seed; long bloom.
May 28 - Jul 7
Bee magnet; self-seeds.
Jun 8 - Aug 7
Sow heat-tolerant types in light shade through summer.
Jun 8 - Jul 7
A June sowing yields a fall storage crop.
Jun 8 - Jul 7
Sow again in June for fall harvest.
What to Plant in Fall
Fall comes early and fast in zone 4, with first frost around September 15. The focus is harvesting and curing storage crops, plus quick cold-hardy greens and roots sown in mid-to-late summer that mature or sweeten as temperatures drop. Plant garlic in October for next year.
Jul 25 - Aug 24
Late-summer sowing yields a fall crop and can overwinter under mulch.
Jul 25 - Aug 24
Cool-season comeback crop; protect from early frost with row cover.
Jul 25 - Sep 3
Fast and frost-tolerant; great for fall.
Jul 25 - Sep 3
Quick fall crop before hard freeze.
Jul 25 - Aug 24
Cool-weather green; pungency mellows with frost.
Jul 25 - Aug 24
Fast Asian green; cold tolerant.
Jul 25 - Aug 24
Very cold hardy rosette green.
Jul 25 - Aug 24
Less likely to bolt sown in late summer for fall.
Jul 14 - Aug 3
More reliable as a fall crop than spring.
Jul 8 - Sep 7
Sweetens markedly after fall frosts; very hardy.
Jul 8 - Aug 17
Fall roots and greens; frost improves flavor.
Jun 8 - Jul 17
Long-season storage root; harvest after first frosts.
Jul 14 - Aug 24
Fall storage radish; harvest before ground freezes.
Jul 25 - Sep 23
Extremely hardy; can be harvested through hard frost and snow.
Jul 25 - Sep 23
Cold-hardy winter salad green under cover.
Sep 24 - Oct 24
Plant cloves 3-4 weeks before ground freezes; mulch heavily for next-summer harvest.
What to Plant in Winter
Outdoor planting in zone 4 winter is effectively nil — the ground is frozen and snow-covered from roughly November through March. Winter is for indoor seed-starting under lights, garden planning and seed ordering, and protecting overwintering crops (mulched garlic, parsnips, cold-frame greens).
Feb 28 - Mar 7
Long-day onions need the earliest indoor start of the season.
Feb 28 - Mar 7
Start under lights; very long season crop.
Feb 28 - Apr 7
Begin slow-growing peppers indoors with bottom heat.
Feb 8 - Apr 7
Needs a long warm start indoors.
Feb 8 - Apr 7
Slow; start very early under lights.
Save a planting from your zone 4 calendar
Choose a crop and a date that suits your local conditions. Create a free account or sign in, then review and save your planting plan. Your saved plan is available on web, iOS, and Android.
Zone calendars are starting points, not local forecasts. Check local frost dates, soil temperature, and the crop's planting instructions before choosing a date. This does not change your profile's zone.
Full Planting Timing Table
Start-indoors, direct-sow, transplant, and harvest windows for every crop in zone 4a.
Vegetables
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Notes |
|---|---|---|---|---|---|
| Amaranth (Leaf) | — | Jun 8 - Jun 17 | — | — | Heat-loving green; sow in warm soil. |
| Arugula | — | Apr 18 - Jun 7 | — | — | Fast and frost-tolerant; great for fall. |
| Asparagus | — | — | Apr 28 - Jun 7 | — | Plant crowns; perennial bed, no harvest year one. |
| Beet | — | Apr 28 - Jun 7 | — | Aug 25 - Oct 24 | Tolerates frost; thin seedlings. |
| Bok Choy / Pak Choi | — | Jul 25 - Aug 24 | — | — | Less likely to bolt sown in late summer for fall. |
| Broccoli | Mar 28 - May 7 | — | — | — | Transplant out mid-May; tolerates light frost. |
| Brussels Sprouts | Mar 28 - May 7 | — | — | Aug 25 - Oct 24 | Long season; start early to mature before hard fall freezes. |
| Bush Bean | — | Jun 8 - Jun 27 | — | — | Direct sow in warm soil; succession sow for steady harvest. |
| Cabbage | Mar 28 - May 7 | — | — | — | Hardy transplant; can set out before last frost. |
| Carrot | — | Apr 28 - Jun 7 | — | — | Sow once soil reaches 45 F; keep evenly moist. |
| Cauliflower | Mar 28 - May 7 | — | — | — | Start indoors for an early summer crop. |
| Celeriac | Mar 8 - May 7 | — | — | — | Slow; start very early under lights. |
| Celery | Mar 8 - May 7 | — | — | — | Needs a long warm start indoors. |
| Claytonia (Miner's Lettuce) | — | Jul 25 - Sep 23 | — | — | Cold-hardy winter salad green under cover. |
| Collards | — | Apr 8 - Jun 7 | — | — | Hardy brassica green; tolerates frost. |
| Corn (Sweet) | — | May 28 - Jun 17 | — | — | Sow in blocks for pollination; choose early varieties. |
| Cucumber | — | Jun 8 - Jun 27 | — | — | Direct sow in warm soil or transplant; trellis to save space. |
| Daikon Radish | — | Jul 14 - Aug 24 | — | — | Fall storage radish; harvest before ground freezes. |
| Edamame (Soybean) | — | Jun 8 - Jun 27 | — | — | Choose early varieties for a single harvest. |
| Eggplant | Mar 18 - May 7 | — | Jun 8 - Jun 17 | — | Needs warmth and a long start; choose short-season varieties. |
| Fava Bean | — | Apr 18 - May 17 | — | — | Very frost hardy; plant as soon as soil thaws. |
| Garden Pea | — | Apr 18 - May 17 | — | — | Very cold tolerant; trellis tall types. |
| Garlic | — | — | Sep 24 - Oct 24 | — | Plant cloves 3-4 weeks before ground freezes; mulch heavily for next-summer harvest. |
| Husk-less / Pie Pumpkin | — | Jun 8 - Jun 17 | — | — | Compact pie types fit the short season well. |
| Kale | — | Jul 8 - Sep 7 | — | — | Sweetens markedly after fall frosts; very hardy. |
| Kohlrabi | Apr 8 - May 7 | — | — | — | Can also be direct-sown in early May. |
| Leek | Feb 28 - Apr 7 | — | — | Aug 25 - Oct 24 | Start under lights; very long season crop. |
| Lettuce | — | Apr 18 - Jun 7 | — | — | Cool-season comeback crop; protect from early frost with row cover. |
| Mizuna | — | Jul 25 - Aug 24 | — | — | Fast Asian green; cold tolerant. |
| Mustard Greens | — | Apr 18 - Jun 7 | — | — | Cool-weather green; pungency mellows with frost. |
| Napa Cabbage | Apr 8 - May 7 | Jul 14 - Aug 3 | — | — | More reliable as a fall crop than spring. |
| Onion (Bulb) | Feb 28 - Apr 7 | — | — | — | Long-day onions need the earliest indoor start of the season. |
| Pac/Corn Salad (Mâche) | — | Jul 25 - Sep 23 | — | — | Extremely hardy; can be harvested through hard frost and snow. |
| Parsnip | — | Apr 8 - Jun 7 | — | — | Slow germinator; needs the full season, sweetens after frost. |
| Pepper (Bell & Hot) | Mar 18 - May 7 | — | Jun 8 - Jun 17 | — | Slow to start; sow 8-10 weeks before last frost with bottom heat. |
| Pole Bean | — | Jun 8 - Jun 27 | — | — | Trellis; longer harvest than bush types. |
| Pole/Runner Bean (Scarlet) | — | Jun 8 - Jun 27 | — | — | Tolerates cool nights better than common beans; ornamental too. |
| Potato | — | — | Apr 28 - Jun 7 | Aug 25 - Sep 23 | Plant seed potatoes ~2 weeks before last frost; hill as they grow. |
| Pumpkin | — | Jun 8 - Jun 17 | — | Aug 25 - Sep 23 | Pick early-maturing types for zone 4 (90-100 days). |
| Radish | — | Apr 18 - Jun 7 | — | — | Quick fall crop before hard freeze. |
| Rhubarb | — | — | Apr 8 - Jun 7 | — | Plant crowns; cold-loving perennial ideal for zone 4. |
| Rutabaga | — | Jun 8 - Jul 17 | — | — | Long-season storage root; harvest after first frosts. |
| Shallot | — | — | Apr 28 - Jun 7 | — | Plant sets in early spring for summer harvest. |
| Snap / Snow Pea | — | Apr 18 - May 17 | — | — | Direct sow early; declines in summer heat. |
| Spinach | — | Apr 18 - Jun 7 | — | — | Late-summer sowing yields a fall crop and can overwinter under mulch. |
| Summer Squash | — | Jun 8 - Jun 27 | — | — | Harvest young and often. |
| Swiss Chard | — | Apr 28 - Jun 7 | — | Aug 25 - Oct 24 | Heat and cold tolerant; long harvest. |
| Tatsoi | — | Jul 25 - Aug 24 | — | — | Very cold hardy rosette green. |
| Tomatillo | Mar 28 - May 7 | — | May 28 - Jun 17 | — | Start with tomatoes; plant at least two for pollination. |
| Tomato | Mar 28 - May 7 | — | May 28 - Jun 17 | — | Start 6-8 weeks before last frost; do not transplant out until after May 25. |
| Turnip | — | Jul 8 - Aug 17 | — | — | Fall roots and greens; frost improves flavor. |
| Winter Squash | — | Jun 8 - Jun 17 | — | Aug 25 - Sep 23 | Choose short-season varieties; needs full season to cure. |
| Zucchini | — | Jun 8 - Jun 27 | — | — | Direct sow after frost; very productive. |
Herbs
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Notes |
|---|---|---|---|---|---|
| Basil | — | — | Jun 8 - Jun 27 | — | Very frost-sensitive; wait until nights are warm. |
| Chives | — | Apr 8 - Jun 7 | — | — | Hardy perennial; returns each spring. |
| Cilantro / Coriander | — | Apr 8 - Jun 7 | — | — | Bolts in heat; succession sow. |
| Dill | — | Apr 8 - Jun 7 | — | — | Direct sow; self-seeds readily. |
| Parsley | Mar 8 - May 7 | — | — | — | Slow to germinate; soak seed first. |
| Sorrel | — | Apr 8 - Jun 7 | — | — | Hardy perennial green. |
| Summer Savory | — | Jun 8 - Jun 17 | — | — | Warm-season annual herb. |
Fruits
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Notes |
|---|---|---|---|---|---|
| Ground Cherry | Mar 28 - May 7 | — | May 28 - Jun 17 | — | Slow germinator; start 8 weeks early. |
| Muskmelon / Cantaloupe | — | — | Jun 8 - Jun 27 | — | Use transplants and black plastic; choose 70-75 day varieties. |
| Strawberry | — | — | Apr 8 - Jun 7 | — | Set out bare-root crowns; mulch for winter survival. |
| Watermelon | — | — | Jun 8 - Jun 27 | — | Only short-season icebox types reliably ripen; use transplants. |
Flowers
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Notes |
|---|---|---|---|---|---|
| Borage | — | May 28 - Jul 7 | — | — | Bee magnet; self-seeds. |
| Calendula | — | Apr 8 - Jun 7 | — | — | Cold-tolerant; direct sow early. |
| Cosmos | — | May 28 - Jul 7 | — | — | Easy from seed; long bloom. |
| Marigold | — | — | May 28 - Jul 7 | — | Plant after frost; deters some pests. |
| Nasturtium | — | May 28 - Jul 7 | — | — | Edible flowers; thrives in poor soil. |
| Snapdragon | Mar 8 - May 7 | — | — | — | Frost tolerant; start early for long bloom. |
| Sunflower | — | May 28 - Jul 7 | — | — | Direct sow; choose shorter-season varieties for seed heads. |
| Sweet Pea | — | Apr 8 - Jun 7 | — | — | Loves cool weather; sow as soon as soil is workable. |
| Zinnia | — | May 28 - Jul 7 | — | — | Heat-loving cut flower; sow after frost. |
Zone 4a vs Zone 4b
USDA divides zone 4 into two half-zones 5°F apart. Zone 4a is the cooler one; here is how its frost dates compare with zone 4b and the zone 4 average.
| Zone 4a | Zone 4 | Zone 4b | |
|---|---|---|---|
| Winter low | −30 to −25°F | −30 to −20°F | −25 to −20°F |
| Last spring frost | Jun 1 | May 25 | May 18 |
| First fall frost | Sep 8 | Sep 15 | Sep 22 |
| Growing season | 99 days | 113 days | 127 days |
Not sure which half you're in? The half-zone comes from your area's average coldest winter night, so check the USDA map for your ZIP code. Your own microclimate — slope, shelter, pavement, elevation — can move dates as much as the half-zone does.
Zone 4a Growing Tips
- ✓ Start warm-season crops (tomatoes, peppers, eggplant, onions, leeks) indoors under grow lights 6-12 weeks before the late-May last frost — direct sowing leaves too little season for them to mature.
- ✓ Choose short-season, cold-adapted varieties: look for tomatoes, melons, corn, and squash rated under 70-90 days to maturity so they finish before the mid-September frost.
- ✓ Use season-extension tools aggressively — row covers, low tunnels, black plastic mulch, and cold frames buy weeks on both ends and let heat-lovers like melons and peppers actually ripen.
- ✓ Plant garlic in October, then mulch heavily (6-8 inches of straw) to prevent frost heaving over the long winter for a strong summer harvest.
- ✓ Lean into cold-hardy crops that thrive here — kale, Brussels sprouts, carrots, parsnips, leeks, and rutabaga sweeten after frost and store or overwinter well under mulch.
- ✓ Watch the wide frost window: the last spring frost can come as late as June 5 and the first fall frost as early as September 5, so keep row cover handy at both ends of the season.
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Sign Up FreeFrequently Asked Questions
What can I plant in spring in zone 4a?
In zone 4a, spring planting includes Tomato, Pepper (Bell & Hot), Eggplant, Tomatillo, Ground Cherry, Onion (Bulb), Leek, Celery, and more. See the spring section above for each crop's timing.
What is the last frost date for zone 4a?
The average last spring frost date for USDA zone 4a is Jun 1. The first fall frost typically arrives around Sep 8, giving a growing season of approximately 99 days.
When is the first frost in zone 4a?
The average first fall frost in USDA zone 4a arrives around Sep 8. That is an average, not a guarantee — the actual first frost varies by up to 2 weeks either way, so watch your local forecast from a few weeks before that date and have row covers ready for tender crops still in the ground.
When can I start seeds indoors in zone 4a?
In zone 4a, start crops like Tomato indoors around Mar 28 - May 7. Check the seasonal sections above for each crop's indoor-sowing window.
What can I plant in fall in zone 4a?
Fall planting in zone 4a includes Spinach, Lettuce, Arugula, Radish, Mustard Greens, Mizuna, Tatsoi, Bok Choy / Pak Choi, and more.
How long is the growing season in zone 4a?
Zone 4a has an average growing season of 99 days, from the last spring frost around Jun 1 to the first fall frost around Sep 8.
What is the difference between zone 4a and zone 4b?
Zone 4a is the cooler half of USDA zone 4, with average coldest winter nights of −30 to −25°F. Compared with the zone 4 averages (last frost May 25, first frost Sep 15), zone 4a's last spring frost is about a week later (Jun 1) and its first fall frost about a week earlier (Sep 8), so zone 4b gardeners plant about two weeks earlier in spring and later in fall than zone 4a.
What to plant right now
Month-specific guides for zone 4, hand-tuned to current frost dates and crop windows.
- What to Plant in October: Garlic Month, Cover Crops, and the Southern Fall Garden — What to plant in October: garlic goes in across zones 3-7, cover crops hit their deadline, and zones 8-10 plant the best garden of their year.
Learn more: When to plant vegetables by zone