Frost dates for Knox, IN
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 26
typical year
Safe to plant
May 12
frost is over in 9 of 10 years
First fall frost
October 19
typical year
Growing season
174 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 | – | Mar 29 – Apr 12 | – |
| Spinach | – | Mar 15 – Apr 5 | Aug 24 – Sep 7 |
| Lettuce | – | Mar 29 – Apr 19 | Aug 24 – Sep 7 |
| Radishes | – | Mar 29 – May 10 | Sep 7 – 21 |
| Onions | – | Mar 29 – Apr 12 | – |
| Potatoes | – | Apr 5 – 19 | – |
| Carrots | – | Apr 5 – 26 | Jul 27 – Aug 10 |
| Beets | – | Mar 29 – Apr 12 | Aug 10 – 24 |
| Kale | Feb 15 – Mar 1 | Mar 29 – Apr 12 | Aug 10 – 24 |
| Broccoli | Feb 15 – Mar 1 | Apr 12 – 26 | Aug 10 – 24 |
| Cabbage | Feb 1 – 15 | Mar 29 – Apr 12 | Aug 10 – 24 |
| Garlic | – | – | Sep 7 – 28 |
| 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 – Aug 10 | – |
| 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 26 | April 12 |
| Fall frost before | October 5 | October 19 | October 31 |
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 15 (April 30 in a late year), and the first one in fall around October 30.
Towns that use these dates
This is the nearest NOAA station with frost records for 3 towns.
Knox, North Judson, Hamlet
Where these dates come from
NOAA weather station KNOX WWTP, IN US (USC00124657), 1991–2020 climate normals. It's the nearest station for 5 zip codes, all within 10 miles:
46340, 46366, 46531, 46532, 46534
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.