Ames, Iowa planting calendar and frost dates
Ames is in USDA hardiness zone 5b. The last spring frost typically comes around April 26 and the first fall frost around October 8, giving about 164 frost-free days a year.
- Hardiness zone
- Zone 5b
- Typical last frost
- April 26
- Typical first frost
- October 8
- Frost-free season
- 164 days
Frost dates in Ames
Last spring frost
- April 11Risky: frost later than this in 9 years out of 10
- April 26Typical: a later frost in half of years
- May 9Safe: a later frost only 1 year in 10
First fall frost
- September 23Risky: frost earlier than this 1 year in 10
- October 8Typical: an earlier frost in half of years
- October 21Late: frost before this in 9 years out of 10
The growing season between the typical last and first frosts is about 164 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 14 and returns around October 19.
NOAA U.S. Climate Normals 1991-2020 for Ames Muni Airport, 3.2 miles SSW 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 Ames
January
Start indoors: onions
February
Start indoors: broccoli, cabbages, cauliflower, collard greens, kale, leeks, onions, oregano, parsley, peppers, petunias, ranunculus, rosemary, snapdragons
March
Start indoors: basil, black-eyed susans, broccoli, cabbages, cauliflower, celery, chives, cilantro, collard greens, eggplants, ginger, leeks, lettuce, marigolds, nasturtiums, oregano, parsley, peppers, petunias, ranunculus, rosemary, sage, snapdragons, spinach, swiss chard, tomatoes
Plant or sow outdoors: beets, black-eyed susans, blackberries, blueberries, broccoli, cauliflower, chives, cilantro, collard greens, figs, garlic, gladioli, grapes, grass seed, hollyhocks, kale, leeks, onions, 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, collard greens, 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: cucumbers, pumpkins, winter squash, zinnias, zucchini
Plant or sow outdoors: asparagus, basil, bermudagrass, cantaloupes, celery, centipedegrass, chives, cilantro, cosmos, cucumbers, dahlias, dill, eggplants, garden mums, ginger, gladioli, grapes, green beans, green onions, kentucky bluegrass, lavenders, lettuce, lilies, marigolds, mints, nasturtiums, okra, oregano, parsley, peanuts, peppers, perennial ryegrass, petunias, pumpkins, ranunculus, rosemary, sage, spinach, st. augustinegrass, sunflowers, sweet corn, sweet peas, sweet potatoes, swiss chard, tall fescue, thyme, tomatoes, watermelons, winter squash, zoysiagrass, zucchini
June
Plant or sow outdoors: bermudagrass, celery, centipedegrass, cosmos, green onions, okra, peanuts, st. augustinegrass, sweet potatoes, zinnias, zoysiagrass
July
Plant or sow outdoors: bermudagrass, centipedegrass, st. augustinegrass, zoysiagrass
Plant for fall: bearded irises, beets, broccoli, brussels sprouts, cabbages, carrots, cauliflower, collard greens, lettuce, peas, radishes, snapdragons, spinach, swiss chard, turnips
August
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 Ames
All 2 of Ames's main ZIP codes take their frost dates from Ames Muni Airport, so the dates on this page apply across the city. Every one of them is in zone 5b.
Planting dates for popular crops in Ames
| Plant | Start indoors | Plant or sow outdoors | Fall planting |
|---|---|---|---|
| Tomatoes | Mar 20 to Apr 3 | May 15 to 29 | — |
| Strawberries | — | Mar 15 to 29 | — |
| Lettuce | Mar 1 to 15 | Apr 19 to May 3 | Jul 9 to Aug 13 |
| Cilantro | Mar 15 to 29 | Apr 26 to May 3 | — |
| Basil | Mar 27 to Apr 10 | May 15 to 22 | — |
| Potatoes | — | Apr 18 to 25 | — |
| Garlic | — | Mar 15 to 29 | Oct 8 to 22 |
| Onions | Jan 4 to Feb 15 | Mar 29 to Apr 12 | — |
| Cucumbers | Apr 17 to May 1 | May 15 to 29 | — |
| Pumpkins | Apr 17 to May 1 | May 15 to 29 | — |
| Peppers | Feb 27 to Mar 27 | May 15 to 29 | — |
| Carrots | — | Apr 5 to 26 | Jul 16 to Aug 6 |
| Sweet Potatoes | — | May 27 to Jun 3 | — |
| Watermelons | Apr 10 to 24 | May 15 to 29 | — |
| Sweet Corn | — | Apr 26 to May 10 | — |
| Green Beans | — | May 15 to 29 | — |
| Zucchini | Apr 17 to May 1 | May 15 to 29 | — |
| Broccoli | Feb 8 to Mar 1 | Mar 29 to Apr 12 | Jul 23 to Aug 20 |
| Peas | — | Mar 15 to 29 | Jul 16 to 30 |
| Spinach | Mar 15 to 22 | Apr 19 to May 3 | Jul 30 to Sep 3 |
| Sunflowers | — | Apr 26 to May 17 | — |
| Zinnias | May 15 to 22 | Jun 12 to 26 | — |
| Tulips | — | — | Aug 27 to Oct 22 |
| Daffodils | — | — | Aug 27 to Oct 8 |
| Grass Seed | — | Mar 15 to 29 | Aug 27 to Sep 10 |
Nearby cities
- Ankeny, IA zone 5b, last frost Apr 23
- Des Moines, IA zone 5b, last frost Apr 18
- West Des Moines, IA zone 5b, last frost Apr 18
- Waterloo, IA zone 5a, last frost Apr 27
- Cedar Rapids, IA zone 5a, last frost Apr 28
- Iowa City, IA zone 5b, last frost Apr 21
Planting in IowaAbout zone 5bPrintable calendar for Ames
Questions
When is the last frost in Ames?
Around April 26 in a typical year, based on NOAA's 1991-2020 records for Ames Muni Airport. There is still a 1 in 10 chance of frost after May 9.
What planting zone is Ames in?
USDA hardiness zone 5b (2023 map). The zone tells you which perennials survive the winter; planting dates depend on frost dates instead.
When should I plant tomatoes in Ames?
Start seeds indoors March 20 to April 3 and set plants out May 15 to 29.
When is the first frost in Ames?
Around October 8 in a typical year, and before September 23 about 1 year in 10.