Zone 4b Gardening Guide
Everything you need to grow a thriving garden in USDA Hardiness Zone 4b — Upper Midwest / Northern New England. Frost dates, planting calendar, and the best plants for your climate.
🌱 Get a personalized Zone 4b plan → Free trialWhat Is Zone 4b?
USDA Hardiness Zone 4b covers Upper Midwest / Northern New England, including cities like Minneapolis, MN · St. Paul, MN · Portland, ME. The zone experiences minimum winter temperatures between -25 to -20°F, which determines which perennials and woody plants survive winter outdoors.
With a growing season of 138 days, Zone 4b gardeners need to be strategic about timing to maximize harvests. The key is aligning your planting schedule with the frost window.
Pro tip: Your exact ZIP code matters. Zone 4b spans a range of microclimates — elevation, urban heat islands, and proximity to water can shift your personal frost dates by 1–3 weeks. Cloche uses your ZIP to give you precise, location-specific recommendations.
Best Vegetables for Zone 4b
These vegetables thrive in Zone 4b's climate and growing season length:
| Vegetable | Start Seeds Indoors | Transplant Outside | Harvest Window |
|---|---|---|---|
| Tomatoes | Mar 1–20 | May 10–20 | Aug–Oct |
| Peppers (short season) | Mar 1–20 | May 10–20 | Aug–Oct |
| Cucumbers | Mar 1–20 | May 10–20 | Aug–Oct |
| Beans | Mar 1–20 | May 10–20 | Aug–Oct |
| Peas | Mar 1–20 | May 10–20 | Aug–Oct |
| Lettuce | Mar 1–20 | May 10–20 | Aug–Oct |
| Kale | Mar 1–20 | May 10–20 | Aug–Oct |
Top Plants This Season
Flowers for Zone 4b
These flowering plants are proven performers in Zone 4b:
- Marigolds
- Zinnias
- Coneflower
- Russian Sage
- Peony
Herbs for Zone 4b
Grow these herbs successfully in Zone 4b:
- Basil
- Chives
- Dill
- Parsley
- Thyme
Planting Calendar for Zone 4b
| Activity | When |
|---|---|
| Start seeds indoors | Mar 1–20 |
| Transplant warm-season crops | May 10–20 |
| Direct sow warm-season crops | May 10–20 |
| Harvest window | Aug–Oct |
| Last frost (average) | May 10 |
| First fall frost (average) | Sept 25 |
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Your Zone 4b Garden, Personalized
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