Delaware planting calendar

When to plant basil in Delaware — sow, transplant & harvest dates

Delaware is mostly USDA zone 7b (range 7a-8a). Dates below are derived from basil's frost tolerance and Delaware's frost window — not generic national averages.

Basil planting timetable for Delaware

Stage	When in Delaware	Anchor
Start seeds indoors	early March (March 4)	6 weeks before the last frost (mid-April)
Transplant outside	late April (April 22)	7 days after the last frost (mid-April)
First harvest (estimate)	late June (June 21)	~60 days from transplant

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why Delaware's climate shifts the basil dates

Delaware's last spring frost averages mid-April and first fall frost late October, which sets the whole planting clock. Delaware is small and mild, moderated by the Atlantic and Delaware Bay, with a long, productive mid-Atlantic season. Wait for warm soil — basil stall in cold ground even after the air warms, so don't rush them out.

Basil is one of the most cold-sensitive common herbs — it sulks below 10 °C and dies in light frost. Wait a full week after the last spring frost before moving transplants outside, or direct-sow two weeks after frost when soil hits 18 °C.

Frost-risk note

Don't plant before mid-April — even a light frost will kill seedlings overnight. In the northern Piedmont near Wilmington (zone 7a) the safe date runs a week or two later.

Regional variation within Delaware

the northern Piedmont near Wilmington (zone 7a) runs roughly 1-2 weeks behind the state average; the Atlantic coast and lower Delmarva (zone 8a) can plant 1-2 weeks earlier.

Wilmington — USDA zone 7b
Dover — USDA zone 7b
Newark — USDA zone 7b
Rehoboth Beach — USDA zone 8a

What else to plant in Delaware around then

Pair the post-frost slot with other warm-season crops — peppers, beans, squash, and cucumbers.

Quick-grow guide

Sun: Full sun — 6+ hours direct.
Soil temperature for germination: 20-25 °C (68-77 °F).
Spacing: 8-12 inches (20-30 cm) between plants.
Days to harvest: ~60 days from planting out.

Frequently asked questions

When is the best time to plant basil in Delaware?

In Delaware (mostly USDA zone 7b), sow basil indoors around early March, transplant outdoors late April (after the last frost, mid-April), and harvest from late June. Basil are frost-tender — a single light frost kills seedlings, so they only go outside once frost danger has fully passed and the soil is warm.

What USDA zone is Delaware?

Most of Delaware sits in USDA hardiness zone 7b, with the state spanning roughly 7a-8a from the northern Piedmont near Wilmington (zone 7a) to the Atlantic coast and lower Delmarva (zone 8a). The last spring frost averages mid-April and the first fall frost late October.

Can you grow basil in Delaware?

Yes. Delaware's dominant zone 7b supports basil — the key is timing. Basil are frost-tender — a single light frost kills seedlings, so they only go outside once frost danger has fully passed and the soil is warm.

Does the planting date change across Delaware?

the northern Piedmont near Wilmington (zone 7a) runs roughly 1-2 weeks behind the state average; the Atlantic coast and lower Delmarva (zone 8a) can plant 1-2 weeks earlier.

What else can I plant in Delaware around the same time?

Pair the post-frost slot with other warm-season crops — peppers, beans, squash, and cucumbers.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.