Fall in zone 5bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 50842 (Cromwell, 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, Creston 2 SW, IA (4 miles away).
- Average last spring frostApr 2850% chance of a 32°F freeze after this date
- Average first fall frostOct 1150% chance of a 32°F freeze by this date
- Growing season (frost-free)164 daysmedian, 32°F threshold
- USDA hardiness zone5b-15 to -10°F avg. coldest night
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This week in your yard
As of Oct 18, 2026, from your frost dates, zone and soil temperature. Lawn timing · Vegetables · Pruning · Plants
Soil temperature now
2-inch depth
No soil station with a fresh reading within 62 miles.
4-inch depth
No soil station with a fresh reading within 62 miles.
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 50842 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
No soil reading near this ZIP. Typical extension timing for your region: spring 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 28 |
| 10% (cautious: only 1 year in 10 freezes later) | May 9 |
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 24 |
| 50% (the "average" first frost) | Oct 11 |
| 90% (late: most years have frozen by now) | Oct 26 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 6 | Oct 1 |
| 32°F (freeze) | Apr 28 | Oct 11 |
| 28°F (hard freeze) | Apr 17 | Oct 23 |
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 50842
Dates count from your average last spring frost (Apr 28) and first fall frost (Oct 11). 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 3–17 | May 5–19 (transplant) | – |
| Pepper (sweet and hot) | Feb 17–Mar 3 | May 12–26 (transplant) | – |
| Eggplant | Feb 17–Mar 3 | May 12–26 (transplant) | – |
| Tomatillo | Mar 3–17 | May 5–19 (transplant) | – |
| Lettuce | Mar 3–17 | Apr 7–28 (transplant) Mar 31–May 12 (sow outdoors) | Aug 16–Sep 6 (transplant) Aug 2–30 (sowing) |
| Spinach | – | Mar 17–Apr 7 (sow outdoors) | Aug 16–Sep 6 (sowing) |
| Kale | Mar 3–17 | Mar 31–Apr 14 (transplant) Mar 31–Apr 14 (sow outdoors) | Jul 19–Aug 16 (transplant) Jul 5–Aug 2 (sowing) |
| Collards | Mar 3–17 | Mar 31–Apr 28 (transplant) Mar 31–Apr 28 (sow outdoors) | Jul 19–Aug 16 (transplant) Jul 5–Aug 2 (sowing) |
| Broccoli | Feb 17–Mar 3 | Mar 31–Apr 14 (transplant) | Jul 5–Aug 2 (transplant) |
| Cabbage | Feb 17–Mar 3 | Mar 31–Apr 14 (transplant) | Jul 5–Aug 2 (transplant) |
| Cauliflower | Feb 17–Mar 3 | Apr 14–28 (transplant) | Jul 5–Aug 2 (transplant) |
| Brussels sprouts | Feb 3–17 | Mar 31–Apr 14 (transplant) | Jun 21–Jul 12 (transplant) |
| Kohlrabi | Mar 3–17 | Mar 31–Apr 14 (transplant) Mar 31–Apr 14 (sow outdoors) | Aug 2–16 (sowing) |
| Bok choy / Asian greens | – | Mar 31–Apr 14 (sow outdoors) | Aug 16–30 (sowing) |
| Arugula | – | Mar 31–Apr 28 (sow outdoors) | Aug 16–Sep 13 (sowing) |
| Mustard greens | – | Mar 31–Apr 21 (sow outdoors) | Aug 16–30 (sowing) |
| Swiss chard | Mar 17–31 | Apr 14–May 5 (transplant) Apr 14–May 12 (sow outdoors) | Aug 2–16 (sowing) |
| Beet | – | Mar 31–Apr 28 (sow outdoors) | Aug 2–16 (sowing) |
| Carrot | – | Apr 7–May 5 (sow outdoors) | Jul 19–Aug 2 (sowing) |
| Radish | – | Mar 24–May 5 (sow outdoors) | Aug 30–Sep 13 (sowing) |
| Turnip | – | Mar 31–Apr 21 (sow outdoors) | Aug 2–16 (sowing) |
| Parsnip | – | Apr 7–28 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 3–31 (sow outdoors) | Jul 19–Aug 2 (sowing) |
| Onion (bulbing) | Feb 3–17 | Mar 17–31 (transplant) | – |
| Green onion / scallion | – | Mar 17–Apr 14 (sow outdoors) | Aug 2–16 (sowing) |
| Leek | Feb 3–17 | Mar 31–Apr 14 (transplant) | – |
| Garlic | – | – | Aug 30–Sep 27 (sowing) |
| Shallot | – | Mar 17–31 (transplant) | Aug 30–Sep 27 (sowing) |
| Potato | – | Mar 31–Apr 14 (transplant) | Jun 21–Jul 5 (transplant) |
| Sweet potato | – | May 19–Jun 2 (transplant) | – |
| Sweet corn | – | May 5–19 (sow outdoors) | – |
| Bean, bush (snap) | – | May 5–19 (sow outdoors) | – |
| Bean, pole | – | May 5–19 (sow outdoors) | – |
| Lima bean | – | May 12–26 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 19–Jun 9 (sow outdoors) | – |
| Cucumber | Mar 31–Apr 7 | May 5–19 (transplant) May 5–19 (sow outdoors) | – |
| Summer squash / zucchini | Mar 31–Apr 7 | May 5–19 (transplant) May 5–19 (sow outdoors) | – |
| Winter squash | Mar 31–Apr 7 | May 5–19 (transplant) May 5–19 (sow outdoors) | – |
| Pumpkin | – | May 5–19 (sow outdoors) | – |
| Watermelon | Mar 31–Apr 7 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 31–Apr 7 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Okra | Mar 17–31 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Celery | Feb 3–17 | May 5–12 (transplant) | – |
| Basil | Mar 17–31 | May 5–19 (transplant) May 5–19 (sow outdoors) | – |
| Cilantro | – | Apr 14–May 12 (sow outdoors) | Aug 16–30 (sowing) |
| Parsley | Feb 17–Mar 3 | Apr 14–28 (transplant) Apr 7–28 (sow outdoors) | – |
| Dill | – | Apr 28–May 12 (sow outdoors) | Aug 16–30 (sowing) |
| Sunflower | – | Apr 28–May 12 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 31–Apr 14 (transplant) | – |
| Rhubarb (crowns) | – | Mar 31–Apr 14 (transplant) | – |
| Strawberry (plants) | – | Mar 31–Apr 14 (transplant) | Aug 2–30 (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: Creston 2 SW, IA (NOAA GHCN-Daily ID USC00131962), elevation 1,296 ft, 3.5 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Corning, IA | 16 mi | Apr 27 | Oct 12 |
| Greenfield, IA | 18 mi | Apr 25 | Oct 12 |
| Mt Ayr, IA | 26 mi | Apr 25 | Oct 12 |
The average last-frost dates of these stations span 3 days, a rough guide to local variation. See data sources & methods.
Frost questions for 50842
When is the last frost in 50842?
The average (50% chance) last spring freeze of 32°F for ZIP 50842 is April 28. For a more cautious planting date, use May 9, when only 1 year in 10 still sees a later freeze.
When is the first frost in 50842?
The average first fall freeze is October 11. In 1 year in 10 it comes by September 24.
What hardiness zone is 50842?
ZIP 50842 is in USDA zone 5b (-15 to -10°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 50842 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
50801 Creston 50859 Prescott 50851 Lenox 50858 Orient 50831 Arispe 50861 Shannon City 50830 Afton 50841 Corning
Other ZIP codes in Union County
50254 50801 50830 50831 50861 All Union County frost dates · Iowa frost dates
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- Freeze alerts
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Free. One weekly email plus alerts when your ZIP has a frost or a soil-temperature change worth acting on. After you submit, Kit (our email provider) sends a confirmation email: check your email and click the link to confirm. You aren't subscribed until you do. We collect only your email address and ZIP, sent to Kit to deliver The Dial. Unsubscribe anytime.