When to plant in Delaware
Delaware spans USDA hardiness zones 7a-7b. Average last spring frost: mid April. Average first fall frost: late October. This calendar is anchored to University of Delaware Cooperative Extension's recommendations, with timing adjusted for the dominant climate zone of the state.
Delaware at a glance
| USDA hardiness zones | 7a-7b |
| Region | Mid-Atlantic |
| Average last spring frost | mid April |
| Average first fall frost | late October |
| Primary Extension service | University of Delaware Cooperative Extension |
What grows particularly well in Delaware
These are the crops, ornamentals, and trees University of Delaware Cooperative Extension highlights as well-suited to Delaware's climate:
- tomato
- sweet corn
- watermelon
- peach
- azalea
- dogwood
Delaware planting calendar
Dates are approximate and based on the dominant USDA zone for the state. For zone-specific timing, use the zone finder by ZIP code and frost date lookup tools.
Spring planting (after last frost: mid April)
Cool-season vegetables (start 2-6 weeks before last frost outdoors): lettuce, spinach, peas, radishes, carrots, beets, kale, broccoli transplants, cabbage transplants.
Warm-season vegetables (after last frost, soil 60F+): tomato transplants, pepper transplants, beans (direct sow), cucumbers, squash, melons. See the seed starting timeline tool for indoor start dates.
Annual flowers (after last frost): zinnia, marigold, cosmos, sunflower, nasturtium.
Perennials, shrubs, trees: Plant in spring after soil thaws but before summer heat. Best window in Delaware: 4-6 weeks after last frost.
Summer (June - August)
Maintenance season for most Delaware gardens. Mulch heavily, water deeply (1 inch per week), pinch back mums for fall bloom, hand-pull weeds, harvest summer vegetables. Plant fall vegetable starts indoors by mid-July.
Fall planting (before first frost: late October)
Cool-season vegetables (6-8 weeks before first frost): lettuce, spinach, radish, kale, broccoli, cabbage transplants. Per Penn State Extension, fall vegetable production can equal or exceed spring production with proper timing.
Spring-flowering bulbs: tulip, daffodil, allium, crocus, hyacinth. Plant 4-6 weeks before ground freezes. In Delaware: typically October-November.
Perennials, shrubs, trees: Fall is the best planting season for woody plants in most of Delaware - cooler temperatures + autumn rains reduce transplant stress. Plant 6+ weeks before first hard freeze.
Garlic: Plant cloves in October-November. Harvest the following July.
Winter (December - February)
Most of Delaware is in dormancy. Tasks: order seeds, plan next year, dormant prune fruit trees (February), order bare-root plants for spring delivery. Avoid foot traffic on frozen lawns.
Common Delaware challenges
Coastal salt spray and storm surge; humid summers with brown rot on stone fruit; sandy coastal soil; deer pressure inland. For region-specific guidance, see our Mid-Atlantic regional gardening guide.
Where to get Delaware-specific advice
The most reliable source for local growing advice is your county Extension office. University of Delaware Cooperative Extension has county offices that provide free soil testing, plant disease diagnosis, and growing recommendations specific to your microclimate.
Visit University of Delaware Cooperative Extension for the office nearest you.
Related tools and guides
- Find your USDA zone by ZIP code
- Look up your average frost dates
- Seasonal care calendar by zone
- Seed starting timeline calculator
- Mid-Atlantic regional gardening guide