Delaware planting calendar

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

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

Rhubarb planting timetable for Delaware

Stage	When in Delaware	Anchor
Direct-sow outside	late March (March 25)	21 days before the last frost (mid-April)
First harvest (estimate)	late September (September 23)	~547 days from direct sow

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 rhubarb 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 — rhubarb stall in cold ground even after the air warms, so don't rush them out.

Rhubarb is planted as divisions or crowns in early spring while the soil is still cool, 2-3 weeks before the last frost; it is extremely cold-hardy and actually requires winter chilling to break dormancy (reliably hardy to zone 3, marginal in zones 9-10 where inadequate chilling reduces vigour). Do not harvest in year one; take only 2-3 stalks per plant in year two; harvest freely from year three onward, always leaving at least 3-4 strong stalks per crown. Never eat the leaves — rhubarb foliage contains toxic oxalates at harmful concentrations.

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

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

Quick-grow guide

Sun: Full sun — 6+ hours direct (tolerates light afternoon shade in hot zones).
Soil temperature for germination: Soil 4-10 °C (40-50 °F) at crown planting.
Spacing: 36-48 inches (90-120 cm) between plants.
Days to harvest: ~547 days from planting out.

Frequently asked questions

When is the best time to plant rhubarb in Delaware?

In Delaware (mostly USDA zone 7b), direct-sow rhubarb late March (before the last frost, mid-April), and harvest from late September. Rhubarb are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

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 rhubarb in Delaware?

Yes. Delaware's dominant zone 7b supports rhubarb — the key is timing. Rhubarb are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

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.