Frost dates for Osage, IA
When the last spring frost and first fall frost usually come, and when to plant, from 30 years of NOAA weather records.
Last spring frost
April 30
typical year
Safe to plant
May 12
frost is over in 9 of 10 years
First fall frost
October 9
typical year
Growing season
163 days
frost-free, typical year
Frost watch this week
Tonight's and the next six nights' lows from the National Weather Service forecast for the station's location. Frost: 32°F or colder. Possible frost: 33–36°F, mostly in low spots on clear, still nights.
When to plant
Counted from this page's frost dates. Warm-season crops wait for the safe-to-plant date.
| Crop | Start indoors | Plant outside | Fall planting |
|---|---|---|---|
| Cool-season crops | |||
| Peas | – | Apr 2 – 16 | – |
| Spinach | – | Mar 19 – Apr 9 | Aug 14 – 28 |
| Lettuce | – | Apr 2 – 23 | Aug 14 – 28 |
| Radishes | – | Apr 2 – May 14 | Aug 28 – Sep 11 |
| Onions | – | Apr 2 – 16 | – |
| Potatoes | – | Apr 9 – 23 | – |
| Carrots | – | Apr 9 – 30 | Jul 17 – 31 |
| Beets | – | Apr 2 – 16 | Jul 31 – Aug 14 |
| Kale | Feb 19 – Mar 5 | Apr 2 – 16 | Jul 31 – Aug 14 |
| Broccoli | Feb 19 – Mar 5 | Apr 16 – 30 | Jul 31 – Aug 14 |
| Cabbage | Feb 5 – 19 | Apr 2 – 16 | Jul 31 – Aug 14 |
| Garlic | – | – | Aug 28 – Sep 18 |
| Warm-season crops | |||
| Tomatoes | Mar 17 – 31 | May 12 – 26 | – |
| Peppers | Mar 10 – 24 | May 19 – Jun 2 | – |
| Cucumbers | – | May 12 – Jun 2 | – |
| Zucchini | – | May 12 – Jun 9 | – |
| Pumpkins | – | May 12 – Jun 2 | – |
| Green beans | – | May 12 – Jul 31 | – |
| Sweet corn | – | May 12 – Jun 9 | – |
| Basil | Apr 7 – 21 | May 19 – 26 | – |
Onions: from sets. Green beans: until 10 weeks before the first fall frost. Garlic: harvest next summer.
The year at a glance
Start indoors Plant outside Fall planting
The chance of frost, by date
| 1 year in 10 | Half of years | 9 years in 10 | |
|---|---|---|---|
| Spring frost after | May 12 | April 30 | April 14 |
| Fall frost before | September 25 | October 9 | October 21 |
Frost here means 32°F or colder. Read across: in 1 year in 10, spring frost carries on past the first date, which is why that date is the safe-to-plant date.
Hard freeze (28°F)
A hard freeze kills most garden plants, even hardy ones. The last one in spring usually comes around April 17 (April 30 in a late year), and the first one in fall around October 20.
Towns that use these dates
This is the nearest NOAA station with frost records for 8 towns.
Osage, St. Ansgar, Riceville, Stacyville, Rudd, McIntire, Mitchell, Orchard
Where these dates come from
NOAA weather station OSAGE, IA US (USC00136305), 1991–2020 climate normals. It's the nearest station for 8 zip codes, all within 16 miles:
50454, 50455, 50460, 50461, 50466, 50471, 50472, 50476
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.