Delaware Planting Zones by City and ZIP Code
Delaware runs from zones 7a to 8a; 95% of its ZIPs are 7b, Wilmington is 7b and Dover is 7b.
Delaware runs from zones 7a to 8a
The coldest night of the winter averages 0°F to 5°F in the coldest of Delaware’s ZIP codes and 10°F to 15°F in the warmest. Most of the state is zone 7b.
Planting zones of Delaware cities
| City | Zone | Coldest night, on average | Since 2012 |
|---|---|---|---|
| Wilmington19801 | 7b | 5°F to 10°F | half a zone warmer than 2012 (7a) |
| Dover19901 | 7b | 5°F to 10°F | half a zone warmer than 2012 (7a) |
| Newark19711 | 7b | 5°F to 10°F | half a zone warmer than 2012 (7a) |
| Lewes19958 | 7b | 5°F to 10°F | same as 2012 |
| Georgetown19947 | 7b | 5°F to 10°F | half a zone warmer than 2012 (7a) |
Tap a ZIP for that address’s frost dates and this month’s jobs.
Find your zone anywhere in Delaware
A ZIP code or a town gives you its zone, how it moved since 2012, the frost dates at the nearest NOAA station, and the jobs for this month timed from them.
What to plant in Delaware this month
The calendar for Delaware's main zone, from vegetables to pruning and winter protection, each job tied to the extension page it comes from. Pick a month, or read the whole year below it.
Timed from the median frost dates of the 7 NOAA stations in Delaware’s zone 7b: last spring frost Apr 7, first fall frost Nov 4. Your own ZIP’s frost dates move every window, so the ZIP tool times them for you.
Pick a month above to see every job in it.
The year at a glance
- Start vegetable seeds indoorsDec to Mar
- Sow vegetables in the gardenMar to Apr
- Sow the fall vegetable gardenJul to Sep
- Set out transplantsMar to Apr
- Plant trees and shrubsFeb 24 to Apr 21 and Oct 21 to Dec 9
- Plant garlicOct 21 to Nov 25
- Plant tulips and other spring bulbsNov 11 to Nov 18
- Divide fall-blooming perennialsMar 17 to Apr 28
- Divide spring and summer-blooming perennialsSep 23 to Nov 4
- Prune trees and summer-flowering shrubs while dormantJan 27 to Mar 10
- Prune spring-flowering shrubs after they bloomMar 24 to May 19
- Put hardware cloth around young tree trunksNov 4 to Dec 16
- Cut back perennials after a hard freezeNov 11 to Dec 9
What changed in Delaware since 2012
Every ZIP on both mapsCompared ZIP by ZIP from the 2023 and 2012 USDA tables; 93 Delaware ZIP codes appear in both.
Why Delaware’s zones moved
Of the cities above, Wilmington went from 7a to 7b, Dover went from 7a to 7b, Newark went from 7a to 7b and Georgetown went from 7a to 7b.
The USDA explains the national picture: “When compared to the 2012 map, the 2023 version reveals that about half of the country shifted to the next warmer half zone, and the other half of the country remained in the same half zone.” The new map uses 1991 to 2020 and more than 13,000 weather stations, so it draws Delaware’s hills, valleys and cities more finely than the 2012 map did.
A warmer zone changes which perennials and shrubs come through the winter, not when the garden gets planted; that still follows the frost dates.
Frost dates and seed starting in Delaware
Delaware planting zone questions
Planting zones by state
Sources. USDA Plant Hardiness Zone Map, ZIP code tables (2023 and 2012), PRISM Climate Group, Oregon State University; USDA Plant Hardiness Zone Map; USDA Unveils Updated Plant Hardiness Zone Map (USDA Agricultural Research Service, November 15, 2023); NOAA NCEI U.S. Climate Normals 1991-2020, annual/seasonal, by station (v1.0.1); NC State Extension Gardener Plant Toolbox. Zones are read from the PRISM ZIP code tables, read Oct 9, 2026; a ZIP code’s zone is the zone at its center. The calendar’s extension sources are listed on the planting zones page and under each job.