Blackwell, MO frost dates
Last spring frostApr 11median date
First fall frostOct 28median date
Growing season200 daysfrost-free
Hardiness zone6bZone 6b
How Blackwell compares
- In 8 years out of 10, the last spring frost in Blackwell falls between March 26 and April 30, a 35-day window. The first fall frost falls between October 14 and November 8.
- The median last frost is 1 day earlier than the Missouri median of Apr 12.
- Its 200-day growing season is longer than 62% of the 938 Missouri places with a regular frost season (state median 195 days).
- The last frost is 11 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 103 nights a year at or below 32°F.
- Compared with Saint Charles, MO, 80 km away, the last frost here is 2 days later than there and the growing season is the same length.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 26 |
| 50% (median) | April 11 |
| 10% (safe for tender plants) | April 30 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 14 |
| 50% (median) | October 28 |
| 90% (late) | November 8 |
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 Blackwell, MO
Blackwell, MO frost dates — last frost Apr 11, first frost Oct 28, zone 6b. whenisthelastfrost.com
Crop
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Start indoors: Jan 17 to Jan 31Transplant outside: Mar 14 to Mar 28
Start indoors: Jan 31 to Feb 14Transplant outside: Apr 25 to May 9
Start indoors: Jan 31 to Feb 14Transplant outside: Apr 25 to May 9
Start indoors: Feb 14 to Feb 28Transplant outside: Apr 18 to May 2
Start indoors: Feb 14 to Feb 28Transplant outside: Mar 21 to Apr 4Sow outdoors: Mar 14 to Apr 18Plant for fall: Sep 2 to Sep 30
Start indoors: Feb 14 to Feb 28Transplant outside: Mar 14 to Mar 28Sow outdoors: Mar 14 to Mar 28Plant for fall: Aug 19 to Sep 9
Start indoors: Feb 14 to Feb 28Transplant outside: Mar 28 to Apr 11Plant for fall: Jul 22 to Aug 12
Start indoors: Feb 14 to Feb 28Transplant outside: Mar 21 to Apr 4Plant for fall: Jul 22 to Aug 12
Start indoors: Feb 14 to Feb 28Transplant outside: Mar 28 to Apr 11Plant for fall: Jul 22 to Aug 12
Start indoors: Feb 28 to Mar 14Transplant outside: May 2 to May 16Sow outdoors: May 2 to May 16
Start indoors: Feb 28 to Mar 14Transplant outside: Apr 18 to May 2
Sow outdoors: Feb 28 to Mar 21Plant for fall: Aug 5 to Aug 26
Sow outdoors: Feb 28 to Mar 21Plant for fall: Sep 2 to Sep 23
Sow outdoors: Mar 7 to Apr 18Plant for fall: Sep 16 to Oct 7
Start indoors: Mar 14 to Mar 21Transplant outside: Apr 25 to May 2Sow outdoors: Apr 18 to May 2Plant for fall: Aug 12 to Aug 26
Start indoors: Mar 14 to Mar 21Sow outdoors: Apr 18 to May 2Plant for fall: Aug 19 to Sep 2
Start indoors: Mar 14 to Mar 21Sow outdoors: Apr 18 to May 2
Start indoors: Mar 14 to Mar 21Transplant outside: Apr 25 to May 9
Sow outdoors: Mar 21 to Apr 18Plant for fall: Aug 5 to Aug 19
Sow outdoors: Mar 21 to Apr 18Plant for fall: Aug 19 to Sep 2
Sow outdoors: Mar 21 to Apr 11
Sow outdoors: Mar 28 to Apr 25Plant for fall: Aug 19 to Sep 2
Sow outdoors: Mar 28 to Apr 18Plant for fall: Sep 2 to Sep 23
Sow outdoors: Apr 18 to May 9Plant for fall: Aug 12 to Aug 26
Sow outdoors: Apr 18 to May 2
Transplant outside: Apr 25 to May 16
Plant for fall: Oct 14 to Nov 18
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Blackwell, MO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 17 – Jan 31 | Mar 14 – Mar 28 | — | — |
| Peppers | Jan 31 – Feb 14 | Apr 25 – May 9 | — | — |
| Eggplant | Jan 31 – Feb 14 | Apr 25 – May 9 | — | — |
| Tomatoes | Feb 14 – Feb 28 | Apr 18 – May 2 | — | — |
| Lettuce | Feb 14 – Feb 28 | Mar 21 – Apr 4 | Mar 14 – Apr 18 | Sep 2 – Sep 30 |
| Kale | Feb 14 – Feb 28 | Mar 14 – Mar 28 | Mar 14 – Mar 28 | Aug 19 – Sep 9 |
| Broccoli | Feb 14 – Feb 28 | Mar 28 – Apr 11 | — | Jul 22 – Aug 12 |
| Cabbage | Feb 14 – Feb 28 | Mar 21 – Apr 4 | — | Jul 22 – Aug 12 |
| Cauliflower | Feb 14 – Feb 28 | Mar 28 – Apr 11 | — | Jul 22 – Aug 12 |
| Okra | Feb 28 – Mar 14 | May 2 – May 16 | May 2 – May 16 | — |
| Basil | Feb 28 – Mar 14 | Apr 18 – May 2 | — | — |
| Peas | — | — | Feb 28 – Mar 21 | Aug 5 – Aug 26 |
| Spinach | — | — | Feb 28 – Mar 21 | Sep 2 – Sep 23 |
| Radishes | — | — | Mar 7 – Apr 18 | Sep 16 – Oct 7 |
| Cucumbers | Mar 14 – Mar 21 | Apr 25 – May 2 | Apr 18 – May 2 | Aug 12 – Aug 26 |
| Zucchini & Summer Squash | Mar 14 – Mar 21 | — | Apr 18 – May 2 | Aug 19 – Sep 2 |
| Winter Squash & Pumpkins | Mar 14 – Mar 21 | — | Apr 18 – May 2 | — |
| Melons & Watermelon | Mar 14 – Mar 21 | Apr 25 – May 9 | — | — |
| Carrots | — | — | Mar 21 – Apr 18 | Aug 5 – Aug 19 |
| Beets | — | — | Mar 21 – Apr 18 | Aug 19 – Sep 2 |
| Potatoes | — | — | Mar 21 – Apr 11 | — |
| Swiss Chard | — | — | Mar 28 – Apr 25 | Aug 19 – Sep 2 |
| Cilantro | — | — | Mar 28 – Apr 18 | Sep 2 – Sep 23 |
| Green Beans | — | — | Apr 18 – May 9 | Aug 12 – Aug 26 |
| Sweet Corn | — | — | Apr 18 – May 2 | — |
| Sweet Potatoes | — | Apr 25 – May 16 | — | — |
| Garlic | — | — | — | Oct 14 – Nov 18 |
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 Potosi 4 Sw, MO weather station, 26 km away (elevation 1,106 ft (337 m)).
Frost dates near Blackwell
- Tiff Apr 11 · Oct 28
- De Soto Apr 9 · Oct 26
- Cadet Apr 11 · Oct 28
- Fletcher Apr 9 · Oct 26
- Bonne Terre Apr 13 · Oct 21
- Mineral Point Apr 11 · Oct 28
- Valles Mines Apr 13 · Oct 21
- Richwoods Apr 11 · Oct 28
- Hematite Apr 9 · Oct 26
- French Village Apr 13 · Oct 21
Frequently asked questions
When is the last frost in Blackwell, MO?
The median last spring frost in Blackwell, MO is April 11. 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 Blackwell, MO?
The median first fall frost is October 28, with about a 10% chance of frost before October 14.
How long is the growing season in Blackwell, MO?
About 200 days between the median last spring frost and first fall frost.
What planting zone is Blackwell, MO?
Blackwell, MO is in USDA hardiness zone 6b.