In Duluth, the average last spring frost is May 15 and the average first fall frost is Oct 9, a growing season of about 147 days (zone 5a). Start tomatoes indoors around Apr 3 and move them outside from May 29. Plant garlic Oct 16 to Oct 23, one to two weeks after the first fall frost.
Duluth at a glance
- Last spring frost
- May 15 (average)
- First fall frost
- Oct 9 (average)
- Frost-free season
- About 147 days
- Hardiness zone
- 5a (USDA)
- Weather stations
- Duluth Harbor Stn, MN; Superior, WI; and Duluth, MN, 1991 to 2020 normals. GrowSmart's dates are the median of these stations, to within 3 days
An average frost date means frost is still possible after it in about half of years. GrowSmart times tender crops like tomatoes, peppers and basil after this date, not on it.
What to plant in Duluth this month (January)
Nothing is scheduled to be sown or planted in Duluth in January. Next up: start onions indoors on Mar 6.
What to plant in Duluth this month (February)
Nothing is scheduled to be sown or planted in Duluth in February. Next up: start onions indoors on Mar 6.
What to plant in Duluth this month (March)
- Start onions indoors: Mar 6
Coming up in early April: start tomatoes indoors (Apr 3), start peppers indoors (Apr 3), start eggplant indoors (Apr 3), start lettuce indoors (Apr 3), start kale indoors (Apr 10), start broccoli indoors (Apr 10) and start cabbage indoors (Apr 10).
What to plant in Duluth this month (April)
- Start tomatoes indoors: Apr 3
- Start peppers indoors: Apr 3
- Start eggplant indoors: Apr 3
- Start lettuce indoors: Apr 3
- Start kale indoors: Apr 10
- Start broccoli indoors: Apr 10
- Start cabbage indoors: Apr 10
- Start basil indoors: Apr 17
- Direct sow spinach: Apr 24
- Direct sow peas: Apr 24
- Direct sow radishes: Apr 24
Coming up in early May: transplant lettuce (May 1), direct sow carrots (May 1), start cucumbers indoors (May 1), start zucchini indoors (May 1), start winter squash indoors (May 1), direct sow beets (May 8), transplant kale (May 8), transplant broccoli (May 8), transplant cabbage (May 8) and direct sow potatoes (May 8).
What to plant in Duluth this month (May)
- Transplant lettuce: May 1
- Direct sow carrots: May 1
- Start cucumbers indoors: May 1
- Start zucchini indoors: May 1
- Start winter squash indoors: May 1
- Direct sow beets: May 8
- Transplant kale: May 8
- Transplant broccoli: May 8
- Transplant cabbage: May 8
- Direct sow potatoes: May 8
- Transplant onions: May 15
- Transplant cucumbers: May 22
- Transplant zucchini: May 22
- Transplant winter squash: May 22
- Direct sow beans: May 22
- Transplant tomatoes: May 29
- Transplant peppers: May 29
- Transplant eggplant: May 29
- Transplant basil: May 29
What to plant in Duluth this month (June)
Nothing is scheduled to be sown or planted in Duluth in June. Next up: sow peas for a fall harvest on Jul 31.
What to plant in Duluth this month (July)
- Sow peas for a fall harvest: Jul 31
- Sow kale for a fall harvest: Jul 31
Coming up in early August: sow lettuce for a fall harvest (Aug 14).
What to plant in Duluth this month (August)
- Sow lettuce for a fall harvest: Aug 14
- Sow spinach for a fall harvest: Aug 21
Coming up in early September: sow radishes for a fall harvest (Sep 4).
What to plant in Duluth this month (September)
- Sow radishes for a fall harvest: Sep 4
What to plant in Duluth this month (October)
- Plant garlic: Oct 16 to Oct 23
What to plant in Duluth this month (November)
Nothing is scheduled to be sown or planted in Duluth in November. Next up: start onions indoors on Mar 6.
What to plant in Duluth this month (December)
Nothing is scheduled to be sown or planted in Duluth in December. Next up: start onions indoors on Mar 6.
Duluth planting calendar
| Crop | Start indoors | Plant outside | Harvest |
|---|---|---|---|
| Tomatoes | Apr 3 | Transplant May 29 | From Aug 15 |
| Peppers | Apr 3 | Transplant May 29 | From Aug 9 |
| Eggplant | Apr 3 | Transplant May 29 | From Aug 12 |
| Basil | Apr 17 | Transplant May 29 | From Jul 10 |
| Onions (from seed) | Mar 6 | Transplant May 15 | From Aug 23 |
| Lettuce | Apr 3 | Transplant May 1Fall: direct sow Aug 14 | From Jun 10Fall: from Sep 23 |
| Spinach | n/a | Direct sow Apr 24Fall: direct sow Aug 21 | From Jun 3Fall: from Sep 30 |
| Peas | n/a | Direct sow Apr 24Fall: direct sow Jul 31 | From Jun 23Fall: from Sep 29 |
| Radishes | n/a | Direct sow Apr 24Fall: direct sow Sep 4 | From May 19Fall: from Sep 29 |
| Carrots | n/a | Direct sow May 1 | From Jul 10 |
| Beets | n/a | Direct sow May 8 | From Jul 2 |
| Kale | Apr 10 | Transplant May 8Fall: direct sow Jul 31 | From Jul 2Fall: from Sep 24 |
| Broccoli | Apr 10 | Transplant May 8 | From Jul 12 |
| Cabbage | Apr 10 | Transplant May 8 | From Jul 17 |
| Cucumbers | May 1 | Transplant May 22 | From Jul 16 |
| Zucchini | May 1 | Transplant May 22 | From Jul 11 |
| Winter squash | May 1 | Transplant May 22 | From Aug 20 |
| Beans | n/a | Direct sow May 22 | From Jul 16 |
| Potatoes | n/a | Direct sow May 8 | From Jul 27 |
| Garlic | n/a | Plant cloves Oct 16 to Oct 23 | Around Aug 7 the next year |
Dates are for one planting of each crop, from Duluth's average frost dates. Tomatoes are indeterminate, lettuce is looseleaf and beans are bush beans. Harvest dates are when the first picking is usually ready. Garlic follows University of Minnesota Extension (see below).
Fall planting in Duluth
Plant garlic Oct 16 to Oct 23. That is one to two weeks after Duluth's average first fall frost of Oct 9, the timing University of Minnesota Extension recommends, so the cloves root before winter without sending shoots up. Harvest comes around Aug 7 the following summer. How to plant garlic in Duluth.
Shallots: GrowSmart's plan has you plant shallot sets in fall in zone 5 and warmer, and in spring in colder zones.
Cool-season crops GrowSmart schedules for a fall harvest in Duluth:
- Peas: sow Jul 31, ready from about Sep 29
- Kale: sow Jul 31, ready from about Sep 24
- Lettuce: sow Aug 14, ready from about Sep 23
- Spinach: sow Aug 21, ready from about Sep 30
- Radishes: sow Sep 4, ready from about Sep 29
Nearby planting calendars
Duluth planting questions
When is the last frost in Duluth?
The average last spring frost in Duluth is May 15, and the average first fall frost is Oct 9, from 1991 to 2020 climate normals at 3 nearby weather stations. Frost is still possible after the spring date in about half of years.
When should I start tomato seeds in Duluth?
Start tomatoes indoors around Apr 3, 8 weeks before moving them outside around May 29, which is two weeks after the average last frost.
What can I plant in Duluth in fall?
Garlic goes in Oct 16 to Oct 23. For fall harvests, sow peas and kale around Jul 31, lettuce around Aug 14, spinach around Aug 21 and radishes around Sep 4.