Duluth, Minnesota planting calendar and frost dates
Duluth is in USDA hardiness zone 4b. The last spring frost typically comes around May 6 and the first fall frost around October 9, giving about 154 frost-free days a year.
- Typical last frost
- May 6
- Typical first frost
- October 9
- Frost-free season
- 154 days
Frost dates in Duluth
Last spring frost
- April 24Risky: frost later than this in 9 years out of 10
- May 6Typical: a later frost in half of years
- May 25Safe: a later frost only 1 year in 10
First fall frost
- September 24Risky: frost earlier than this 1 year in 10
- October 9Typical: an earlier frost in half of years
- October 24Late: frost before this in 9 years out of 10
The growing season between the typical last and first frosts is about 154 days. Frost here means a low of 32°F at the weather station. A hard freeze (28°F), which damages most hardy crops too, typically ends around April 24 and returns around October 24.
NOAA U.S. Climate Normals 1991-2020 for Superior, 4.2 miles SSE of the city center. Low-lying and rural spots often frost later in spring and earlier in fall than airports and city centers.
What to plant each month in Duluth
January
Start indoors: onions
February
Start indoors: broccoli, cabbages, cauliflower, collard greens, kale, leeks, onions, oregano, parsley, petunias, ranunculus, rosemary, snapdragons
March
Start indoors: black-eyed susans, broccoli, cabbages, cauliflower, chives, cilantro, collard greens, kale, leeks, lettuce, marigolds, nasturtiums, oregano, parsley, petunias, ranunculus, rosemary, sage, snapdragons, spinach, swiss chard
Plant or sow outdoors: black-eyed susans, blueberries, garlic, grapes, grass seed, hollyhocks, onions, peas, poppies, raspberries, rhubarb, strawberries, turnips, wildflowers
April
Start indoors: celery, cilantro, eggplants, ginger, marigolds, nasturtiums, peppers, ranunculus, spinach, swiss chard, tomatoes, zinnias
Plant or sow outdoors: beets, black-eyed susans, blackberries, blueberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, collard greens, dahlias, dill, figs, garlic, gladioli, grapes, grass seed, hollyhocks, kale, leeks, lettuce, onions, parsley, peas, poppies, radishes, ranunculus, raspberries, rhubarb, roses, snapdragons, spinach, strawberries, swiss chard, turnips, wildflowers
May
Start indoors: basil, cantaloupes, cosmos, cucumbers, eggplants, okra, peppers, pumpkins, tomatoes, watermelons, winter squash, zucchini
Plant or sow outdoors: asparagus, beets, carrots, chives, cilantro, dahlias, dill, figs, garden mums, gladioli, grapes, green onions, lavenders, leeks, lettuce, lilies, marigolds, mints, nasturtiums, oregano, parsley, petunias, potatoes, ranunculus, rosemary, roses, sage, snapdragons, spinach, sunflowers, sweet corn, swiss chard, thyme, zinnias
June
Start indoors: cosmos, cucumbers, okra, pumpkins, winter squash, zucchini
Plant or sow outdoors: asparagus, basil, cantaloupes, cucumbers, eggplants, garden mums, ginger, green beans, green onions, kentucky bluegrass, peppers, perennial ryegrass, pumpkins, st. augustinegrass, sunflowers, sweet corn, sweet peas, tall fescue, tomatoes, watermelons, winter squash, zucchini
July
Plant or sow outdoors: bermudagrass, cantaloupes, celery, centipedegrass, cosmos, cucumbers, eggplants, green beans, green onions, okra, peanuts, peppers, pumpkins, st. augustinegrass, sweet potatoes, tomatoes, watermelons, winter squash, zoysiagrass, zucchini
Plant for fall: bearded irises, beets, broccoli, brussels sprouts, cabbages, carrots, cauliflower, collard greens, lettuce, peas, radishes, snapdragons, spinach, swiss chard, turnips
August
Plant or sow outdoors: bermudagrass, centipedegrass, zoysiagrass
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, carrots, cauliflower, clematis, coneflowers, crocuses, daffodils, daylilies, grass seed, hostas, hydrangeas, kale, lettuce, lilies, ornamental alliums, peonies, radishes, roses, saffron, snapdragons, spinach, swiss chard, tulips, turnips
September
Plant for fall: cabbages, cauliflower, crocuses, daffodils, daylilies, grass seed, hostas, hyacinths, kale, lilies, ornamental alliums, peonies, radishes, saffron, spinach, tulips
October
Plant for fall: crocuses, daffodils, garlic, hyacinths, lilies, ornamental alliums, peonies, tulips
Frost dates and zones by ZIP code in Duluth
All 8 of Duluth's main ZIP codes take their frost dates from Superior, so the dates on this page apply across the city. The hardiness zone is 4a in 55803, and 4b in 55804, 55806, 55807, 55808, 55810, 55811, and 5a in 55802.
| ZIP code | Zone | Weather station | Typical last frost | Typical first frost |
|---|---|---|---|---|
| 55802 | 5a | Superior, 4.2 mi SSE | May 6 | Oct 9 |
| 55803 | 4a | Superior, 4.2 mi SSE | May 6 | Oct 9 |
| 55804 | 4b | Superior, 4.2 mi SSE | May 6 | Oct 9 |
| 55806 | 4b | Superior, 4.2 mi SSE | May 6 | Oct 9 |
| 55807 | 4b | Superior, 4.2 mi SSE | May 6 | Oct 9 |
| 55808 | 4b | Superior, 4.2 mi SSE | May 6 | Oct 9 |
| 55810 | 4b | Superior, 4.2 mi SSE | May 6 | Oct 9 |
| 55811 | 4b | Superior, 4.2 mi SSE | May 6 | Oct 9 |
Planting dates for popular crops in Duluth
| Plant | Start indoors | Plant or sow outdoors | Fall planting |
|---|---|---|---|
| Tomatoes | Apr 26 to May 10 | Jun 21 to Jul 5 | — |
| Strawberries | — | Mar 25 to Apr 8 | — |
| Lettuce | Mar 11 to 25 | Apr 29 to May 13 | Jul 10 to Aug 14 |
| Cilantro | Mar 25 to Apr 8 | May 6 to 13 | — |
| Basil | May 3 to 17 | Jun 21 to 28 | — |
| Potatoes | — | May 19 to 26 | — |
| Garlic | — | Mar 25 to Apr 8 | Oct 9 to 23 |
| Onions | Jan 14 to Feb 25 | Apr 8 to 22 | — |
| Cucumbers | May 24 to Jun 7 | Jun 21 to Jul 5 | — |
| Pumpkins | May 24 to Jun 7 | Jun 21 to Jul 5 | — |
| Peppers | Apr 5 to May 3 | Jun 21 to Jul 5 | — |
| Carrots | — | Apr 15 to May 6 | Jul 17 to Aug 7 |
| Sweet Potatoes | — | Jul 6 to 13 | — |
| Watermelons | May 17 to 31 | Jun 21 to Jul 5 | — |
| Sweet Corn | — | May 19 to Jun 2 | — |
| Green Beans | — | Jun 21 to Jul 5 | — |
| Zucchini | May 24 to Jun 7 | Jun 21 to Jul 5 | — |
| Broccoli | Feb 18 to Mar 11 | Apr 8 to 22 | Jul 24 to Aug 21 |
| Peas | — | Mar 25 to Apr 8 | Jul 17 to 31 |
| Spinach | Mar 25 to Apr 1 | Apr 29 to May 13 | Jul 31 to Sep 4 |
| Sunflowers | — | May 19 to Jun 9 | — |
| Zinnias | Apr 8 to 15 | May 6 to 20 | — |
| Tulips | — | — | Aug 28 to Oct 23 |
| Daffodils | — | — | Aug 28 to Oct 9 |
| Grass Seed | — | Mar 25 to Apr 8 | Aug 28 to Sep 11 |
Nearby cities
- Blaine, MN zone 5a, last frost Apr 30
- Coon Rapids, MN zone 5a, last frost Apr 30
- Brooklyn Park, MN zone 5a, last frost Apr 30
- St. Cloud, MN zone 4b, last frost May 7
- Maple Grove, MN zone 5a, last frost Apr 30
- St. Paul, MN zone 5a, last frost Apr 23
Planting in MinnesotaAbout zone 4bPrintable calendar for Duluth
Questions
When is the last frost in Duluth?
Around May 6 in a typical year, based on NOAA's 1991-2020 records for Superior. There is still a 1 in 10 chance of frost after May 25.
What planting zone is Duluth in?
USDA hardiness zone 4b (2023 map), with parts of the city in zone 5a and 4a. The zone tells you which perennials survive the winter; planting dates depend on frost dates instead.
When should I plant tomatoes in Duluth?
Start seeds indoors April 26 to May 10 and set plants out June 21 to July 5.
When is the first frost in Duluth?
Around October 9 in a typical year, and before September 24 about 1 year in 10.