What to plant this week in Duluth, MN
Duluth gardeners in Zone 4b are navigating the transition from deep winter chill to early spring warmth, with garlic now ready for planting as temperatures hover near the -25°F minimum. This week marks a critical window where outdoor harvests like Brussels sprouts and bush beans begin to mature quickly under the region's rapid temperature swings. With an average last frost date around May 12, it is still too early to transplant anything, but indoor starts can be prepared for late spring.
The next 7 days
Duluth, MNGrowing in Duluth right now
- Soil stays frozen deep into April due to our northern latitude and lake-effect proximity; wait until mid-April before attempting any outdoor bed preparation or tilling. The unique microclimate of the North Shore means frost pockets form easily in low-lying areas near the harbor, so delay planting by a week compared to southern Zone 4b locations.
- Our short growing season requires you to focus exclusively on cold-hardy crops like parsnips and leeks for immediate harvest; warm-season items such as cantaloupe and watermelon must be started indoors now or wait until after the May 12 frost date.
- Heavy spring rains are common in Duluth, often washing away loose topsoil; amend your beds with compost immediately to improve drainage and nutrient retention before the heavy runoff arrives.
Sow this week
1 crops- Garlic
Transplant this week
Nothing is due to go out this week.
Harvest soon
44 crops- Basil
- Borage
- Brussels Sprouts
- Bush Bean
- Cantaloupe
- Celery
- Cleome (Spider Flower)
- Cosmos
- Cowpea (Black-Eyed Pea)
- Cucumber
- Dahlia
- Edamame
- Fennel
- Flour Corn
- French Marigold
- Garden Verbena
- Garlic
- Ghost Pepper (Bhut Jolokia)
- Gourd (Ornamental/Bottle)
- Habanero Pepper
- Honeydew Melon
- Leek
- Lima Bean
- Lisianthus (Prairie Gentian)
- Loofah (Luffa)
- Nasturtium
- Ornamental Sweet Potato Vine
- Parsnip
- Pole Bean
- Potato
- Pumpkin
- Scarlet Runner Bean
- Shiso (Japanese Basil)
- Summer Savory
- Sunflower
- Sweet Corn
- Thai Basil
- Tomatillo
- Vinca (Madagascar Periwinkle)
- Watermelon
- Winter Squash
- Yellow Summer Squash
- Zinnia
- Zucchini
Seasonal tips
- Begin succession sowing bush beans and cucumbers every two weeks for continuous yields through summer.
- Apply a fresh layer of mulch around established plants to retain moisture as spring temperatures fluctuate.
- Prepare your soil beds now that the danger of frost has passed to ensure optimal root growth.
Pest & disease watch
- Late winter rodents may chew through unprotected garlic cloves planted too early or left exposed during brief thaws; consider using hardware cloth cylinders for protection.
- Spring slugs thrive in our damp, lake-effect climate and will target emerging seedlings of basil and beans once snow cover melts.
- Powdery mildew can affect Brussels sprouts and celery if moisture lingers on foliage during cool, wet Duluth springs; ensure good air circulation between plants.
Watering this week
Water deeply in the morning to encourage strong root development while minimizing evaporation and fungal risks.
Since garlic is being sown now, ensure you plant it a few weeks before your average last frost date of May 12 for a robust harvest next fall.
Duluth gardening questions
3Can I plant peppers or tomatoes now in Duluth?
No, you cannot transplant warm-season crops like bell peppers or tomatoes until after the average last frost date of May 12. You can start seeds indoors for these right now to get a head start before moving them outside later.
What can I harvest from my garden this week?
Focus on cold-hardy crops that are already established, such as Brussels sprouts, bush beans, and celery. Items like garlic are ready to be planted now rather than harvested, while warm fruits like watermelon will not produce yet.
How does the Duluth soil affect my garlic planting?
Because our soil freezes deeply, wait until the ground thaws completely in mid-April before planting your garlic cloves. Planting into frozen earth can damage roots or prevent proper establishment in our short growing season.
Other cities in zone 4b
3See the full zone 4b guide → · Plan your Duluth garden in SproutGuide →