Unionville, MD frost dates
Last spring frostApr 2median date
First fall frostNov 6median date
Growing season218 daysfrost-free
Hardiness zone7bZone 7b
How Unionville compares
- In 8 years out of 10, the last spring frost in Unionville falls between March 17 and April 15, a 29-day window. The first fall frost falls between October 23 and November 24.
- The median last frost is 3 days earlier than the Maryland median of Apr 5.
- Its 218-day growing season is longer than 55% of the 431 Maryland places with a regular frost season (state median 216 days).
- The last frost is typical for zone 7b, where the median is Apr 5.
- The weather station records an average of 84 nights a year at or below 32°F.
- Unionville shares its weather station with Frederick, MD, 20 km away, so the two have the same frost dates.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 17 |
| 50% (median) | April 2 |
| 10% (safe for tender plants) | April 15 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 23 |
| 50% (median) | November 6 |
| 90% (late) | November 24 |
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 Unionville, MD
Unionville, MD frost dates — last frost Apr 2, first frost Nov 6, zone 7b. whenisthelastfrost.com
Crop
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Start indoors: Jan 8 to Jan 22Transplant outside: Mar 5 to Mar 19
Start indoors: Jan 22 to Feb 5Transplant outside: Apr 16 to Apr 30
Start indoors: Jan 22 to Feb 5Transplant outside: Apr 16 to Apr 30
Start indoors: Feb 5 to Feb 19Transplant outside: Apr 9 to Apr 23
Start indoors: Feb 5 to Feb 19Transplant outside: Mar 12 to Mar 26Sow outdoors: Mar 5 to Apr 9Plant for fall: Sep 11 to Oct 9
Start indoors: Feb 5 to Feb 19Transplant outside: Mar 5 to Mar 19Sow outdoors: Mar 5 to Mar 19Plant for fall: Aug 28 to Sep 18
Start indoors: Feb 5 to Feb 19Transplant outside: Mar 19 to Apr 2Plant for fall: Jul 31 to Aug 21
Start indoors: Feb 5 to Feb 19Transplant outside: Mar 12 to Mar 26Plant for fall: Jul 31 to Aug 21
Start indoors: Feb 5 to Feb 19Transplant outside: Mar 19 to Apr 2Plant for fall: Jul 31 to Aug 21
Start indoors: Feb 19 to Mar 5Transplant outside: Apr 23 to May 7Sow outdoors: Apr 23 to May 7
Start indoors: Feb 19 to Mar 5Transplant outside: Apr 9 to Apr 23
Sow outdoors: Feb 19 to Mar 12Plant for fall: Aug 14 to Sep 4
Sow outdoors: Feb 19 to Mar 12Plant for fall: Sep 11 to Oct 2
Sow outdoors: Feb 26 to Apr 9Plant for fall: Sep 25 to Oct 16
Start indoors: Mar 5 to Mar 12Transplant outside: Apr 16 to Apr 23Sow outdoors: Apr 9 to Apr 23Plant for fall: Aug 21 to Sep 4
Start indoors: Mar 5 to Mar 12Sow outdoors: Apr 9 to Apr 23Plant for fall: Aug 28 to Sep 11
Start indoors: Mar 5 to Mar 12Sow outdoors: Apr 9 to Apr 23
Start indoors: Mar 5 to Mar 12Transplant outside: Apr 16 to Apr 30
Sow outdoors: Mar 12 to Apr 9Plant for fall: Aug 14 to Aug 28
Sow outdoors: Mar 12 to Apr 9Plant for fall: Aug 28 to Sep 11
Sow outdoors: Mar 12 to Apr 2
Sow outdoors: Mar 19 to Apr 16Plant for fall: Aug 28 to Sep 11
Sow outdoors: Mar 19 to Apr 9Plant for fall: Sep 11 to Oct 2
Sow outdoors: Apr 9 to Apr 30Plant for fall: Aug 21 to Sep 4
Sow outdoors: Apr 9 to Apr 23
Transplant outside: Apr 16 to May 7
Plant for fall: Oct 23 to Nov 27
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Unionville, MD
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 8 – Jan 22 | Mar 5 – Mar 19 | — | — |
| Peppers | Jan 22 – Feb 5 | Apr 16 – Apr 30 | — | — |
| Eggplant | Jan 22 – Feb 5 | Apr 16 – Apr 30 | — | — |
| Tomatoes | Feb 5 – Feb 19 | Apr 9 – Apr 23 | — | — |
| Lettuce | Feb 5 – Feb 19 | Mar 12 – Mar 26 | Mar 5 – Apr 9 | Sep 11 – Oct 9 |
| Kale | Feb 5 – Feb 19 | Mar 5 – Mar 19 | Mar 5 – Mar 19 | Aug 28 – Sep 18 |
| Broccoli | Feb 5 – Feb 19 | Mar 19 – Apr 2 | — | Jul 31 – Aug 21 |
| Cabbage | Feb 5 – Feb 19 | Mar 12 – Mar 26 | — | Jul 31 – Aug 21 |
| Cauliflower | Feb 5 – Feb 19 | Mar 19 – Apr 2 | — | Jul 31 – Aug 21 |
| Okra | Feb 19 – Mar 5 | Apr 23 – May 7 | Apr 23 – May 7 | — |
| Basil | Feb 19 – Mar 5 | Apr 9 – Apr 23 | — | — |
| Peas | — | — | Feb 19 – Mar 12 | Aug 14 – Sep 4 |
| Spinach | — | — | Feb 19 – Mar 12 | Sep 11 – Oct 2 |
| Radishes | — | — | Feb 26 – Apr 9 | Sep 25 – Oct 16 |
| Cucumbers | Mar 5 – Mar 12 | Apr 16 – Apr 23 | Apr 9 – Apr 23 | Aug 21 – Sep 4 |
| Zucchini & Summer Squash | Mar 5 – Mar 12 | — | Apr 9 – Apr 23 | Aug 28 – Sep 11 |
| Winter Squash & Pumpkins | Mar 5 – Mar 12 | — | Apr 9 – Apr 23 | — |
| Melons & Watermelon | Mar 5 – Mar 12 | Apr 16 – Apr 30 | — | — |
| Carrots | — | — | Mar 12 – Apr 9 | Aug 14 – Aug 28 |
| Beets | — | — | Mar 12 – Apr 9 | Aug 28 – Sep 11 |
| Potatoes | — | — | Mar 12 – Apr 2 | — |
| Swiss Chard | — | — | Mar 19 – Apr 16 | Aug 28 – Sep 11 |
| Cilantro | — | — | Mar 19 – Apr 9 | Sep 11 – Oct 2 |
| Green Beans | — | — | Apr 9 – Apr 30 | Aug 21 – Sep 4 |
| Sweet Corn | — | — | Apr 9 – Apr 23 | — |
| Sweet Potatoes | — | Apr 16 – May 7 | — | — |
| Garlic | — | — | — | Oct 23 – Nov 27 |
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 Frederick Police Brks, MD weather station, 23 km away (elevation 381 ft (116 m)).
Frost dates near Unionville
- Libertytown Apr 2 · Nov 6
- New Windsor Apr 22 · Oct 20
- Mount Airy Apr 14 · Oct 29
- New Market Apr 2 · Nov 6
- Woodsboro Apr 22 · Oct 20
- Union Bridge Apr 22 · Oct 20
- Keymar Apr 22 · Oct 20
- New Midway Apr 22 · Oct 20
- Ladiesburg Apr 22 · Oct 20
- Walkersville Apr 2 · Nov 6
Frequently asked questions
When is the last frost in Unionville, MD?
The median last spring frost in Unionville, MD is April 2. There is still about a 10% chance of frost after April 15, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Unionville, MD?
The median first fall frost is November 6, with about a 10% chance of frost before October 23.
How long is the growing season in Unionville, MD?
About 218 days between the median last spring frost and first fall frost.
What planting zone is Unionville, MD?
Unionville, MD is in USDA hardiness zone 7b.