Frost dates for ZIP 51440 (Dedham, IA)
Average last spring and first fall frost dates with 10%, 50% and 90% odds, from NOAA's 1991–2020 climate normals for the nearest weather station, Carroll, IA (11 miles away).
- Average last spring frostApr 2750% chance of a 32°F freeze after this date
- Average first fall frostOct 1050% chance of a 32°F freeze by this date
- Growing season (frost-free)166 daysmedian, 32°F threshold
- USDA hardiness zone5a-20 to -15°F avg. coldest night
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This week in your yard
As of Oct 17, 2026, from your frost dates, zone and soil temperature. Lawn timing · Vegetables · Pruning · Plants
Soil temperature now
2-inch depth
53°F 50–55°F
24-hour average · latest 54°F, as of Oct 17, 10:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Ames (56 mi), Shagbark Hills (61 mi).
4-inch depth
54°F 50–55°F
24-hour average · latest 54°F, as of Oct 17, 10:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Ames (56 mi), Shagbark Hills (61 mi).
Fall: Texas A&M AgriLife times fall pre-emergent (for winter weeds such as annual bluegrass) to soil cooling to about 70°F for several days. The 50–55°F band is the spring trigger. Always read and follow the product label.
7-day forecast and frost risk
The latest National Weather Service 7-day forecast and any Frost Advisory or Freeze Warning for 51440 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 54°F at 4 inches (estimated soil temperature, not a station reading). Fall pre-emergent window is mostly past. Next: spring, when soil reaches 50°F (typically mid-April to early May).
Fertilizer window
Lawn region: North (cool-season). Timing only; always follow the product label.
- Kentucky bluegrass (cool-season): Early fall: Around Labor Day (late August–September); Late fall: Late October–November, before the ground freezes; Late spring: Optional around Memorial Day. Avoid: Early-spring and midsummer feeding (pushes top growth, favors crabgrass).
Plant now
No vegetable planting windows are open this week.
Prune now
No frost-timed pruning windows are open this week.
Spring-flowering shrubs are pruned right after their flowers fade, not by date. See the pruning guide.
Last spring frost odds
| Chance of a 32°F freeze after this date | Date |
|---|---|
| 90% (early: most years still freeze after this) | Apr 14 |
| 50% (the "average" last frost) | Apr 27 |
| 10% (cautious: only 1 year in 10 freezes later) | May 8 |
Most gardeners plant frost-tender crops (tomatoes, peppers, basil) after the 50% date, and closer to the 10% date for less risk.
First fall frost odds
| Chance the first 32°F freeze has happened by this date | Date |
|---|---|
| 10% (early: 1 year in 10 freezes this soon) | Sep 25 |
| 50% (the "average" first frost) | Oct 10 |
| 90% (late: most years have frozen by now) | Oct 24 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 6 | Sep 30 |
| 32°F (freeze) | Apr 27 | Oct 10 |
| 28°F (hard freeze) | Apr 16 | Oct 21 |
n/a means NOAA did not publish a date at that threshold for this station (usually because it rarely gets that cold).
Vegetable planting calendar for 51440
Dates count from your average last spring frost (Apr 27) and first fall frost (Oct 10). Half of years have a frost after the spring date, so give tender crops (tomatoes, peppers, squash) some slack.
| Crop | Start indoors | Spring planting | Fall planting |
|---|---|---|---|
| Tomato | Mar 2–16 | May 4–18 (transplant) | – |
| Pepper (sweet and hot) | Feb 16–Mar 2 | May 11–25 (transplant) | – |
| Eggplant | Feb 16–Mar 2 | May 11–25 (transplant) | – |
| Tomatillo | Mar 2–16 | May 4–18 (transplant) | – |
| Lettuce | Mar 2–16 | Apr 6–27 (transplant) Mar 30–May 11 (sow outdoors) | Aug 15–Sep 5 (transplant) Aug 1–29 (sowing) |
| Spinach | – | Mar 16–Apr 6 (sow outdoors) | Aug 15–Sep 5 (sowing) |
| Kale | Mar 2–16 | Mar 30–Apr 13 (transplant) Mar 30–Apr 13 (sow outdoors) | Jul 18–Aug 15 (transplant) Jul 4–Aug 1 (sowing) |
| Collards | Mar 2–16 | Mar 30–Apr 27 (transplant) Mar 30–Apr 27 (sow outdoors) | Jul 18–Aug 15 (transplant) Jul 4–Aug 1 (sowing) |
| Broccoli | Feb 16–Mar 2 | Mar 30–Apr 13 (transplant) | Jul 4–Aug 1 (transplant) |
| Cabbage | Feb 16–Mar 2 | Mar 30–Apr 13 (transplant) | Jul 4–Aug 1 (transplant) |
| Cauliflower | Feb 16–Mar 2 | Apr 13–27 (transplant) | Jul 4–Aug 1 (transplant) |
| Brussels sprouts | Feb 2–16 | Mar 30–Apr 13 (transplant) | Jun 20–Jul 11 (transplant) |
| Kohlrabi | Mar 2–16 | Mar 30–Apr 13 (transplant) Mar 30–Apr 13 (sow outdoors) | Aug 1–15 (sowing) |
| Bok choy / Asian greens | – | Mar 30–Apr 13 (sow outdoors) | Aug 15–29 (sowing) |
| Arugula | – | Mar 30–Apr 27 (sow outdoors) | Aug 15–Sep 12 (sowing) |
| Mustard greens | – | Mar 30–Apr 20 (sow outdoors) | Aug 15–29 (sowing) |
| Swiss chard | Mar 16–30 | Apr 13–May 4 (transplant) Apr 13–May 11 (sow outdoors) | Aug 1–15 (sowing) |
| Beet | – | Mar 30–Apr 27 (sow outdoors) | Aug 1–15 (sowing) |
| Carrot | – | Apr 6–May 4 (sow outdoors) | Jul 18–Aug 1 (sowing) |
| Radish | – | Mar 23–May 4 (sow outdoors) | Aug 29–Sep 12 (sowing) |
| Turnip | – | Mar 30–Apr 20 (sow outdoors) | Aug 1–15 (sowing) |
| Parsnip | – | Apr 6–27 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 2–30 (sow outdoors) | Jul 18–Aug 1 (sowing) |
| Onion (bulbing) | Feb 2–16 | Mar 16–30 (transplant) | – |
| Green onion / scallion | – | Mar 16–Apr 13 (sow outdoors) | Aug 1–15 (sowing) |
| Leek | Feb 2–16 | Mar 30–Apr 13 (transplant) | – |
| Garlic | – | – | Aug 29–Sep 26 (sowing) |
| Shallot | – | Mar 16–30 (transplant) | Aug 29–Sep 26 (sowing) |
| Potato | – | Mar 30–Apr 13 (transplant) | Jun 20–Jul 4 (transplant) |
| Sweet potato | – | May 18–Jun 1 (transplant) | – |
| Sweet corn | – | May 4–18 (sow outdoors) | – |
| Bean, bush (snap) | – | May 4–18 (sow outdoors) | – |
| Bean, pole | – | May 4–18 (sow outdoors) | – |
| Lima bean | – | May 11–25 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 18–Jun 8 (sow outdoors) | – |
| Cucumber | Mar 30–Apr 6 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Summer squash / zucchini | Mar 30–Apr 6 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Winter squash | Mar 30–Apr 6 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Pumpkin | – | May 4–18 (sow outdoors) | – |
| Watermelon | Mar 30–Apr 6 | May 11–25 (transplant) May 11–25 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 30–Apr 6 | May 11–25 (transplant) May 11–25 (sow outdoors) | – |
| Okra | Mar 16–30 | May 11–25 (transplant) May 11–25 (sow outdoors) | – |
| Celery | Feb 2–16 | May 4–11 (transplant) | – |
| Basil | Mar 16–30 | May 4–18 (transplant) May 4–18 (sow outdoors) | – |
| Cilantro | – | Apr 13–May 11 (sow outdoors) | Aug 15–29 (sowing) |
| Parsley | Feb 16–Mar 2 | Apr 13–27 (transplant) Apr 6–27 (sow outdoors) | – |
| Dill | – | Apr 27–May 11 (sow outdoors) | Aug 15–29 (sowing) |
| Sunflower | – | Apr 27–May 11 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 30–Apr 13 (transplant) | – |
| Rhubarb (crowns) | – | Mar 30–Apr 13 (transplant) | – |
| Strawberry (plants) | – | Mar 30–Apr 13 (transplant) | Aug 1–29 (transplant) |
Typical ranges from university extension planting calendars, adjusted to your frost dates. Probabilities, not guarantees. Fall windows that would overlap spring planting are left out, as are fall crops of frost-tender plants where the frost-free season is under 210 days.
Where these numbers come from
Station: Carroll, IA (NOAA GHCN-Daily ID USC00131233), elevation 1,240 ft, 10.7 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Audubon, IA | 15 mi | May 2 | Oct 3 |
| Jefferson, IA | 23 mi | Apr 26 | Oct 9 |
| Guthrie Ctr, IA | 23 mi | May 2 | Oct 3 |
The average last-frost dates of these stations span 7 days, a rough guide to local variation. See data sources & methods.
Frost questions for 51440
When is the last frost in 51440?
The average (50% chance) last spring freeze of 32°F for ZIP 51440 is April 27. For a more cautious planting date, use May 8, when only 1 year in 10 still sees a later freeze.
When is the first frost in 51440?
The average first fall freeze is October 10. In 1 year in 10 it comes by September 25.
What hardiness zone is 51440?
ZIP 51440 is in USDA zone 5a (-20 to -15°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 51440 right now?
This page shows the latest 2-inch and 4-inch soil temperature from the nearest public soil station (USDA SCAN, NOAA USCRN or TexMesonet), or a labeled estimate when no station is close, against the 50–55°F spring pre-emergent band.
Nearby ZIP codes
51463 Templeton 50058 Coon Rapids 50110 Gray 51444 Halbur 51401 Carroll 50025 Audubon 51443 Glidden 51455 Manning
Other ZIP codes in Carroll County
51401 51430 51436 51443 51444 51451 51452 51455 51459 51463 All Carroll County frost dates · Iowa frost dates
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