USDA hardiness zones in Delaware
| Zone | Avg. extreme minimum | ZIP codes | Example cities |
|---|---|---|---|
| Zone 7b | 5 to 10°F | 66 | Wilmington, Dover, Newark, Middletown |
| Zone 8a | 10 to 15°F | 4 | — |
Growing zone and frost dates by city
| City | Zone | Frost dates |
|---|---|---|
| Wilmington | 7b (5 to 10°F) | Wilmington frost dates |
| Dover | 7b (5 to 10°F) | Dover frost dates |
| Newark | 7b (5 to 10°F) | Newark frost dates |
| Middletown | 7b (5 to 10°F) | Middletown frost dates |
| Milford | 7b (5 to 10°F) | Milford frost dates |
| Smyrna | 7b (5 to 10°F) | Smyrna frost dates |
| Seaford | 7b (5 to 10°F) | Seaford frost dates |
| Georgetown | 7b (5 to 10°F) | Georgetown frost dates |
| Millsboro | 7b (5 to 10°F) | Millsboro frost dates |
| Elsmere | 7b (5 to 10°F) | Elsmere frost dates |
| New Castle | 7b (5 to 10°F) | New Castle frost dates |
Frequently asked questions
What growing zone is Delaware in?
Delaware’s ZIP codes span USDA zones 7b to 8a, and 7b is the most common. Zones vary with elevation and distance from water, so check your own ZIP code.
When should I plant?
Hardiness zones are about winter cold, not planting dates. For timing, use the last spring frost date for your city on our Delaware frost dates page.