Dubuque, Iowa planting calendar and frost dates
Dubuque is in USDA hardiness zone 5a. The last spring frost typically comes around April 19 and the first fall frost around October 21, giving about 184 frost-free days a year.
- Hardiness zone
- Zone 5a
- Typical last frost
- April 19
- Typical first frost
- October 21
- Frost-free season
- 184 days
Frost dates in Dubuque
Last spring frost
- April 4Risky: frost later than this in 9 years out of 10
- April 19Typical: a later frost in half of years
- May 4Safe: a later frost only 1 year in 10
First fall frost
- October 7Risky: frost earlier than this 1 year in 10
- October 21Typical: an earlier frost in half of years
- November 2Late: frost before this in 9 years out of 10
The growing season between the typical last and first frosts is about 184 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 7 and returns around November 1.
NOAA U.S. Climate Normals 1991-2020 for Dubuque L&D 11, 2.5 miles ESE of the city center and 122 feet lower. 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 Dubuque
January
Start indoors: collard greens, leeks, onions, petunias, ranunculus
February
Start indoors: black-eyed susans, broccoli, cabbages, cauliflower, chives, collard greens, kale, leeks, lettuce, marigolds, onions, oregano, parsley, peppers, petunias, ranunculus, rosemary, sage, snapdragons
March
Start indoors: basil, black-eyed susans, cabbages, cauliflower, celery, chives, cilantro, collard greens, eggplants, ginger, lettuce, marigolds, nasturtiums, peppers, ranunculus, sage, snapdragons, spinach, swiss chard, tomatoes
Plant or sow outdoors: beets, black-eyed susans, blackberries, blueberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, collard greens, figs, garlic, gladioli, grapes, grass seed, hollyhocks, kale, leeks, lettuce, onions, parsley, peas, poppies, radishes, ranunculus, raspberries, rhubarb, roses, spinach, strawberries, swiss chard, turnips, wildflowers
April
Start indoors: basil, cantaloupes, cosmos, cucumbers, okra, pumpkins, ranunculus, tomatoes, watermelons, winter squash, zucchini
Plant or sow outdoors: asparagus, beets, black-eyed susans, blackberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, dahlias, dill, figs, garden mums, gladioli, grapes, green onions, lavenders, leeks, lettuce, lilies, marigolds, mints, nasturtiums, onions, oregano, parsley, petunias, potatoes, radishes, ranunculus, rosemary, roses, sage, snapdragons, spinach, sunflowers, sweet corn, swiss chard, thyme, turnips
May
Start indoors: cosmos, cucumbers, okra, pumpkins, winter squash, zinnias, zucchini
Plant or sow outdoors: asparagus, basil, bermudagrass, cantaloupes, celery, centipedegrass, cosmos, cucumbers, eggplants, garden mums, ginger, grapes, green beans, green onions, kentucky bluegrass, lavenders, lilies, marigolds, mints, nasturtiums, okra, oregano, parsley, peanuts, peppers, perennial ryegrass, petunias, pumpkins, rosemary, sage, st. augustinegrass, sunflowers, sweet corn, sweet peas, sweet potatoes, tall fescue, thyme, tomatoes, watermelons, winter squash, zoysiagrass, zucchini
June
Plant or sow outdoors: asparagus, bermudagrass, celery, centipedegrass, cosmos, green onions, okra, peanuts, st. augustinegrass, sweet potatoes, zinnias, zoysiagrass
July
Plant or sow outdoors: bermudagrass, centipedegrass, zoysiagrass
Plant for fall: bearded irises, brussels sprouts, carrots, collard greens, lettuce, peas, snapdragons, swiss chard
August
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, carrots, cauliflower, clematis, collard greens, coneflowers, daylilies, hostas, hydrangeas, kale, lettuce, peas, radishes, roses, saffron, snapdragons, spinach, swiss chard, turnips
September
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, cauliflower, clematis, coneflowers, crocuses, daffodils, daylilies, grass seed, hostas, hyacinths, hydrangeas, kale, lilies, ornamental alliums, peonies, radishes, roses, saffron, spinach, tulips, turnips
October
Plant for fall: crocuses, daffodils, garlic, hyacinths, lilies, ornamental alliums, peonies, tulips
November
Plant for fall: crocuses, garlic, hyacinths, ornamental alliums, tulips
December
Start indoors: onions
Frost dates and zones by ZIP code in Dubuque
Dubuque's 4 main ZIP codes take their frost dates from 2 different NOAA stations: the typical last frost ranges from April 19 in 52001 to April 28 in 52068. Every one of them is in zone 5a.
Planting dates for popular crops in Dubuque
| Plant | Start indoors | Plant or sow outdoors | Fall planting |
|---|---|---|---|
| Tomatoes | Mar 21 to Apr 4 | May 16 to 30 | — |
| Strawberries | — | Mar 8 to 22 | — |
| Lettuce | Feb 22 to Mar 8 | Apr 12 to 26 | Jul 22 to Aug 26 |
| Cilantro | Mar 8 to 22 | Apr 19 to 26 | — |
| Basil | Mar 28 to Apr 11 | May 16 to 23 | — |
| Potatoes | — | Apr 21 to 28 | — |
| Garlic | — | Mar 8 to 22 | Oct 21 to Nov 4 |
| Onions | Dec 28 to Feb 8 | Mar 22 to Apr 5 | — |
| Cucumbers | Apr 18 to May 2 | May 16 to 30 | — |
| Pumpkins | Apr 18 to May 2 | May 16 to 30 | — |
| Peppers | Feb 28 to Mar 28 | May 16 to 30 | — |
| Carrots | — | Mar 29 to Apr 19 | Jul 29 to Aug 19 |
| Sweet Potatoes | — | May 29 to Jun 5 | — |
| Watermelons | Apr 11 to 25 | May 16 to 30 | — |
| Sweet Corn | — | Apr 21 to May 5 | — |
| Green Beans | — | May 16 to 30 | — |
| Zucchini | Apr 18 to May 2 | May 16 to 30 | — |
| Broccoli | Feb 1 to 22 | Mar 22 to Apr 5 | Aug 5 to Sep 2 |
| Peas | — | Mar 8 to 22 | Jul 29 to Aug 12 |
| Spinach | Mar 8 to 15 | Apr 12 to 26 | Aug 12 to Sep 16 |
| Sunflowers | — | Apr 21 to May 12 | — |
| Zinnias | May 17 to 24 | Jun 14 to 28 | — |
| Tulips | — | — | Sep 9 to Nov 4 |
| Daffodils | — | — | Sep 9 to Oct 21 |
| Grass Seed | — | Mar 8 to 22 | Sep 9 to 23 |
Nearby cities
- Cedar Rapids, IA zone 5a, last frost Apr 28
- Davenport, IA zone 5b, last frost Apr 19
- Iowa City, IA zone 5b, last frost Apr 21
- Madison, WI zone 5b, last frost May 1
- Waterloo, IA zone 5a, last frost Apr 27
- Rockford, IL zone 5b, last frost Apr 24
Planting in IowaAbout zone 5aPrintable calendar for Dubuque
Questions
When is the last frost in Dubuque?
Around April 19 in a typical year, based on NOAA's 1991-2020 records for Dubuque L&D 11. There is still a 1 in 10 chance of frost after May 4.
What planting zone is Dubuque in?
USDA hardiness zone 5a (2023 map). The zone tells you which perennials survive the winter; planting dates depend on frost dates instead.
When should I plant tomatoes in Dubuque?
Start seeds indoors March 21 to April 4 and set plants out May 16 to 30.
When is the first frost in Dubuque?
Around October 21 in a typical year, and before October 7 about 1 year in 10.