Fall in zone 5bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 47921 (Boswell, IN)
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, Boswell 4WNW, IN (6 miles away).
- Average last spring frostApr 2550% chance of a 32°F freeze after this date
- Average first fall frostOct 1350% chance of a 32°F freeze by this date
- Growing season (frost-free)169 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
56°F 55°F or warmer
24-hour average · latest 52°F, as of Oct 18, 1:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Champaign 9 SW (60 mi).
4-inch depth
58°F 55°F or warmer
24-hour average · latest 57°F, as of Oct 18, 1:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Champaign 9 SW (60 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 47921 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 58°F at 4 inches (estimated soil temperature, not a station reading). Fall pre-emergent (annual bluegrass, winter weeds): window open as soil cools through the 70s and 60s.
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 13 |
| 50% (the "average" last frost) | Apr 25 |
| 10% (cautious: only 1 year in 10 freezes later) | May 12 |
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 27 |
| 50% (the "average" first frost) | Oct 13 |
| 90% (late: most years have frozen by now) | Oct 25 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 5 | Oct 3 |
| 32°F (freeze) | Apr 25 | Oct 13 |
| 28°F (hard freeze) | Apr 15 | Oct 22 |
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 47921
Dates count from your average last spring frost (Apr 25) and first fall frost (Oct 13). 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 | Feb 28–Mar 14 | May 2–16 (transplant) | – |
| Pepper (sweet and hot) | Feb 14–28 | May 9–23 (transplant) | – |
| Eggplant | Feb 14–28 | May 9–23 (transplant) | – |
| Tomatillo | Feb 28–Mar 14 | May 2–16 (transplant) | – |
| Lettuce | Feb 28–Mar 14 | Apr 4–25 (transplant) Mar 28–May 9 (sow outdoors) | Aug 18–Sep 8 (transplant) Aug 4–Sep 1 (sowing) |
| Spinach | – | Mar 14–Apr 4 (sow outdoors) | Aug 18–Sep 8 (sowing) |
| Kale | Feb 28–Mar 14 | Mar 28–Apr 11 (transplant) Mar 28–Apr 11 (sow outdoors) | Jul 21–Aug 18 (transplant) Jul 7–Aug 4 (sowing) |
| Collards | Feb 28–Mar 14 | Mar 28–Apr 25 (transplant) Mar 28–Apr 25 (sow outdoors) | Jul 21–Aug 18 (transplant) Jul 7–Aug 4 (sowing) |
| Broccoli | Feb 14–28 | Mar 28–Apr 11 (transplant) | Jul 7–Aug 4 (transplant) |
| Cabbage | Feb 14–28 | Mar 28–Apr 11 (transplant) | Jul 7–Aug 4 (transplant) |
| Cauliflower | Feb 14–28 | Apr 11–25 (transplant) | Jul 7–Aug 4 (transplant) |
| Brussels sprouts | Jan 31–Feb 14 | Mar 28–Apr 11 (transplant) | Jun 23–Jul 14 (transplant) |
| Kohlrabi | Feb 28–Mar 14 | Mar 28–Apr 11 (transplant) Mar 28–Apr 11 (sow outdoors) | Aug 4–18 (sowing) |
| Bok choy / Asian greens | – | Mar 28–Apr 11 (sow outdoors) | Aug 18–Sep 1 (sowing) |
| Arugula | – | Mar 28–Apr 25 (sow outdoors) | Aug 18–Sep 15 (sowing) |
| Mustard greens | – | Mar 28–Apr 18 (sow outdoors) | Aug 18–Sep 1 (sowing) |
| Swiss chard | Mar 14–28 | Apr 11–May 2 (transplant) Apr 11–May 9 (sow outdoors) | Aug 4–18 (sowing) |
| Beet | – | Mar 28–Apr 25 (sow outdoors) | Aug 4–18 (sowing) |
| Carrot | – | Apr 4–May 2 (sow outdoors) | Jul 21–Aug 4 (sowing) |
| Radish | – | Mar 21–May 2 (sow outdoors) | Sep 1–15 (sowing) |
| Turnip | – | Mar 28–Apr 18 (sow outdoors) | Aug 4–18 (sowing) |
| Parsnip | – | Apr 4–25 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Feb 28–Mar 28 (sow outdoors) | Jul 21–Aug 4 (sowing) |
| Onion (bulbing) | Jan 31–Feb 14 | Mar 14–28 (transplant) | – |
| Green onion / scallion | – | Mar 14–Apr 11 (sow outdoors) | Aug 4–18 (sowing) |
| Leek | Jan 31–Feb 14 | Mar 28–Apr 11 (transplant) | – |
| Garlic | – | – | Sep 1–29 (sowing) |
| Shallot | – | Mar 14–28 (transplant) | Sep 1–29 (sowing) |
| Potato | – | Mar 28–Apr 11 (transplant) | Jun 23–Jul 7 (transplant) |
| Sweet potato | – | May 16–30 (transplant) | – |
| Sweet corn | – | May 2–16 (sow outdoors) | – |
| Bean, bush (snap) | – | May 2–16 (sow outdoors) | – |
| Bean, pole | – | May 2–16 (sow outdoors) | – |
| Lima bean | – | May 9–23 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 16–Jun 6 (sow outdoors) | – |
| Cucumber | Mar 28–Apr 4 | May 2–16 (transplant) May 2–16 (sow outdoors) | – |
| Summer squash / zucchini | Mar 28–Apr 4 | May 2–16 (transplant) May 2–16 (sow outdoors) | – |
| Winter squash | Mar 28–Apr 4 | May 2–16 (transplant) May 2–16 (sow outdoors) | – |
| Pumpkin | – | May 2–16 (sow outdoors) | – |
| Watermelon | Mar 28–Apr 4 | May 9–23 (transplant) May 9–23 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 28–Apr 4 | May 9–23 (transplant) May 9–23 (sow outdoors) | – |
| Okra | Mar 14–28 | May 9–23 (transplant) May 9–23 (sow outdoors) | – |
| Celery | Jan 31–Feb 14 | May 2–9 (transplant) | – |
| Basil | Mar 14–28 | May 2–16 (transplant) May 2–16 (sow outdoors) | – |
| Cilantro | – | Apr 11–May 9 (sow outdoors) | Aug 18–Sep 1 (sowing) |
| Parsley | Feb 14–28 | Apr 11–25 (transplant) Apr 4–25 (sow outdoors) | – |
| Dill | – | Apr 25–May 9 (sow outdoors) | Aug 18–Sep 1 (sowing) |
| Sunflower | – | Apr 25–May 9 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 28–Apr 11 (transplant) | – |
| Rhubarb (crowns) | – | Mar 28–Apr 11 (transplant) | – |
| Strawberry (plants) | – | Mar 28–Apr 11 (transplant) | Aug 4–Sep 1 (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: Boswell 4WNW, IN (NOAA GHCN-Daily ID USC00120858), elevation 772 ft, 5.7 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Hoopeston, IL | 16 mi | Apr 22 | Oct 19 |
| Attica 2E, IN | 16 mi | Apr 22 | Oct 17 |
| Kentland, IN | 20 mi | Apr 23 | Oct 14 |
The average last-frost dates of these stations span 3 days, a rough guide to local variation. See data sources & methods.
Frost questions for 47921
When is the last frost in 47921?
The average (50% chance) last spring freeze of 32°F for ZIP 47921 is April 25. For a more cautious planting date, use May 12, when only 1 year in 10 still sees a later freeze.
When is the first frost in 47921?
The average first fall freeze is October 13. In 1 year in 10 it comes by September 27.
What hardiness zone is 47921?
ZIP 47921 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 47921 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
47917 Tab 47975 Pine Village 47971 Oxford 47986 Templeton 47944 Fowler 47993 Williamsport 47970 Otterbein 47991 West Lebanon
Other ZIP codes in Benton County
47942 47944 47971 47986 All Benton County frost dates · Indiana frost dates
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Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
- 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.