Delaware planting calendar

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

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

Swiss Chard planting timetable for Delaware

Stage	When in Delaware	Anchor
Start seeds indoors	mid-March (March 18)	4 weeks before the last frost (mid-April)
Transplant outside	early April (April 8)	7 days before the last frost (mid-April)
First harvest (estimate)	early June (June 2)	~55 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 swiss chard 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. Sow early — swiss chard bolt once daytime temperatures hold above 24 °C, so the earlier they go in, the longer the harvest.

Swiss chard is notably more versatile than spinach — it tolerates both light frost (surviving to about -4 °C) and summer heat up to 32 °C, making it a near-year-round crop in Zones 7–10. Direct-sow or transplant 1 week before the last spring frost; chard seed is actually a multi-germ cluster, so thin to final spacing after germination to prevent overcrowding. Unlike spinach, it does not readily bolt in summer, so a single sowing can be harvested by cutting outer leaves repeatedly for 3–4 months.

Frost-risk note

Don't plant before mid-April — a hard freeze can still set young plants back. 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

The same early window suits peas, lettuce, spinach, and onion sets.

Quick-grow guide

Sun: Full sun to partial shade.
Soil temperature for germination: 10-29 °C (50-85 °F).
Spacing: 9-12 inches (23-30 cm) between plants.
Days to harvest: ~55 days from planting out.

Frequently asked questions

When is the best time to plant swiss chard in Delaware?

In Delaware (mostly USDA zone 7b), sow swiss chard indoors around mid-March, transplant outdoors early April (before the last frost, mid-April), and harvest from early June. Swiss Chard are half-hardy — young plants shrug off a light frost but not a hard freeze, so sowing can start a couple of weeks before the last spring frost.

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 swiss chard in Delaware?

Yes. Delaware's dominant zone 7b supports swiss chard — the key is timing. Swiss Chard are half-hardy — young plants shrug off a light frost but not a hard freeze, so sowing can start a couple of weeks before the last spring frost.

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?

The same early window suits peas, lettuce, spinach, and onion sets.

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.