Ironton, MO frost dates
Last spring frostApr 13median date
First fall frostOct 21median date
Growing season191 daysfrost-free
Hardiness zone6bZone 6b
How Ironton compares
- In 8 years out of 10, the last spring frost in Ironton falls between March 28 and April 30, a 33-day window. The first fall frost falls between October 6 and November 1.
- The median last frost is 1 day later than the Missouri median of Apr 12.
- Its 191-day growing season is longer than 34% of the 938 Missouri places with a regular frost season (state median 195 days).
- The last frost is 9 days earlier than the zone 6b median of Apr 22. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6b chart.
- The weather station records an average of 104 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 28 |
| 50% (median) | April 13 |
| 10% (safe for tender plants) | April 30 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 6 |
| 50% (median) | October 21 |
| 90% (late) | November 1 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Ironton, MO
Ironton, MO frost dates — last frost Apr 13, first frost Oct 21, zone 6b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Jan 19 to Feb 2Transplant outside: Mar 16 to Mar 30
Start indoors: Feb 2 to Feb 16Transplant outside: Apr 27 to May 11
Start indoors: Feb 2 to Feb 16Transplant outside: Apr 27 to May 11
Start indoors: Feb 16 to Mar 2Transplant outside: Apr 20 to May 4
Start indoors: Feb 16 to Mar 2Transplant outside: Mar 23 to Apr 6Sow outdoors: Mar 16 to Apr 20Plant for fall: Aug 26 to Sep 23
Start indoors: Feb 16 to Mar 2Transplant outside: Mar 16 to Mar 30Sow outdoors: Mar 16 to Mar 30Plant for fall: Aug 12 to Sep 2
Start indoors: Feb 16 to Mar 2Transplant outside: Mar 30 to Apr 13Plant for fall: Jul 15 to Aug 5
Start indoors: Feb 16 to Mar 2Transplant outside: Mar 23 to Apr 6Plant for fall: Jul 15 to Aug 5
Start indoors: Feb 16 to Mar 2Transplant outside: Mar 30 to Apr 13Plant for fall: Jul 15 to Aug 5
Start indoors: Mar 2 to Mar 16Transplant outside: May 4 to May 18Sow outdoors: May 4 to May 18
Start indoors: Mar 2 to Mar 16Transplant outside: Apr 20 to May 4
Sow outdoors: Mar 2 to Mar 23Plant for fall: Jul 29 to Aug 19
Sow outdoors: Mar 2 to Mar 23Plant for fall: Aug 26 to Sep 16
Sow outdoors: Mar 9 to Apr 20Plant for fall: Sep 9 to Sep 30
Start indoors: Mar 16 to Mar 23Transplant outside: Apr 27 to May 4Sow outdoors: Apr 20 to May 4Plant for fall: Aug 5 to Aug 19
Start indoors: Mar 16 to Mar 23Sow outdoors: Apr 20 to May 4Plant for fall: Aug 12 to Aug 26
Start indoors: Mar 16 to Mar 23Sow outdoors: Apr 20 to May 4
Start indoors: Mar 16 to Mar 23Transplant outside: Apr 27 to May 11
Sow outdoors: Mar 23 to Apr 20Plant for fall: Jul 29 to Aug 12
Sow outdoors: Mar 23 to Apr 20Plant for fall: Aug 12 to Aug 26
Sow outdoors: Mar 23 to Apr 13
Sow outdoors: Mar 30 to Apr 27Plant for fall: Aug 12 to Aug 26
Sow outdoors: Mar 30 to Apr 20Plant for fall: Aug 26 to Sep 16
Sow outdoors: Apr 20 to May 11Plant for fall: Aug 5 to Aug 19
Sow outdoors: Apr 20 to May 4
Transplant outside: Apr 27 to May 18
Plant for fall: Oct 7 to Nov 11
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Ironton, MO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 19 – Feb 2 | Mar 16 – Mar 30 | — | — |
| Peppers | Feb 2 – Feb 16 | Apr 27 – May 11 | — | — |
| Eggplant | Feb 2 – Feb 16 | Apr 27 – May 11 | — | — |
| Tomatoes | Feb 16 – Mar 2 | Apr 20 – May 4 | — | — |
| Lettuce | Feb 16 – Mar 2 | Mar 23 – Apr 6 | Mar 16 – Apr 20 | Aug 26 – Sep 23 |
| Kale | Feb 16 – Mar 2 | Mar 16 – Mar 30 | Mar 16 – Mar 30 | Aug 12 – Sep 2 |
| Broccoli | Feb 16 – Mar 2 | Mar 30 – Apr 13 | — | Jul 15 – Aug 5 |
| Cabbage | Feb 16 – Mar 2 | Mar 23 – Apr 6 | — | Jul 15 – Aug 5 |
| Cauliflower | Feb 16 – Mar 2 | Mar 30 – Apr 13 | — | Jul 15 – Aug 5 |
| Okra | Mar 2 – Mar 16 | May 4 – May 18 | May 4 – May 18 | — |
| Basil | Mar 2 – Mar 16 | Apr 20 – May 4 | — | — |
| Peas | — | — | Mar 2 – Mar 23 | Jul 29 – Aug 19 |
| Spinach | — | — | Mar 2 – Mar 23 | Aug 26 – Sep 16 |
| Radishes | — | — | Mar 9 – Apr 20 | Sep 9 – Sep 30 |
| Cucumbers | Mar 16 – Mar 23 | Apr 27 – May 4 | Apr 20 – May 4 | Aug 5 – Aug 19 |
| Zucchini & Summer Squash | Mar 16 – Mar 23 | — | Apr 20 – May 4 | Aug 12 – Aug 26 |
| Winter Squash & Pumpkins | Mar 16 – Mar 23 | — | Apr 20 – May 4 | — |
| Melons & Watermelon | Mar 16 – Mar 23 | Apr 27 – May 11 | — | — |
| Carrots | — | — | Mar 23 – Apr 20 | Jul 29 – Aug 12 |
| Beets | — | — | Mar 23 – Apr 20 | Aug 12 – Aug 26 |
| Potatoes | — | — | Mar 23 – Apr 13 | — |
| Swiss Chard | — | — | Mar 30 – Apr 27 | Aug 12 – Aug 26 |
| Cilantro | — | — | Mar 30 – Apr 20 | Aug 26 – Sep 16 |
| Green Beans | — | — | Apr 20 – May 11 | Aug 5 – Aug 19 |
| Sweet Corn | — | — | Apr 20 – May 4 | — |
| Sweet Potatoes | — | Apr 27 – May 18 | — | — |
| Garlic | — | — | — | Oct 7 – Nov 11 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Farmington, MO weather station, 26 km away (elevation 899 ft (274 m)).
Frost dates near Ironton
- Pilot Knob Apr 13 · Oct 21
- Arcadia Apr 21 · Oct 16
- Bismarck Apr 13 · Oct 21
- Doe Run Apr 13 · Oct 21
- Belleview Apr 11 · Oct 28
- Caledonia Apr 11 · Oct 28
- Knob Lick Apr 21 · Oct 16
- Farmington Apr 13 · Oct 21
- Middle Brook Apr 9 · Oct 26
- Annapolis Apr 9 · Oct 26
Frequently asked questions
When is the last frost in Ironton, MO?
The median last spring frost in Ironton, MO is April 13. There is still about a 10% chance of frost after April 30, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Ironton, MO?
The median first fall frost is October 21, with about a 10% chance of frost before October 6.
How long is the growing season in Ironton, MO?
About 191 days between the median last spring frost and first fall frost.
What planting zone is Ironton, MO?
Ironton, MO is in USDA hardiness zone 6b.