New Jersey planting calendar

When to plant sweet potatoes in New Jersey — sow, transplant & harvest dates

New Jersey is mostly USDA zone 7a (range 6a-7b). Dates below are derived from sweet potatoes's frost tolerance and New Jersey's frost window — not generic national averages.

Sweet potatoes planting timetable for New Jersey

Stage	When in New Jersey	Anchor
Start seeds indoors	early March (March 4)	6 weeks before the last frost (mid-April)
Transplant outside	early May (May 6)	21 days after the last frost (mid-April)
First harvest (estimate)	mid-August (August 19)	~105 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 New Jersey's climate shifts the sweet potatoes dates

New Jersey's last spring frost averages mid-April and first fall frost late October, which sets the whole planting clock. New Jersey has a mild mid-Atlantic climate with a long season, moderated by the ocean and Delaware Bay along the coast. Wait for warm soil — sweet potatoes stall in cold ground even after the air warms, so don't rush them out.

Sweet potatoes are extremely frost-tender and demand warm soil — do not transplant slips until soil temperature at 4-inch depth holds at 18 °C (65 °F) or above, typically 3 weeks after the last spring frost. Short-season zones (z5-6) should start slips indoors under lights 5-6 weeks early to ensure 100-120 frost-free days. Avoid zones 3-4 without a floating row cover season-extension strategy; in z9-11 slips can go out as early as late March.

Frost-risk note

Don't plant before mid-April — even a light frost will kill seedlings overnight. In the northwest Highlands near High Point (zone 6a) the safe date runs a week or two later.

Regional variation within New Jersey

the northwest Highlands near High Point (zone 6a) runs roughly 1-2 weeks behind the state average; the Atlantic shore and inner harbor (zone 7b) can plant 1-2 weeks earlier.

Newark — USDA zone 7b
Jersey City — USDA zone 7b
Trenton — USDA zone 7a
Atlantic City — USDA zone 7b

What else to plant in New Jersey around then

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

Quick-grow guide

Sun: Full sun — 6-8 hours direct.
Soil temperature for germination: Soil 18-24 °C (65-75 °F) for slip rooting.
Spacing: 12-18 inches (30-45 cm) between plants.
Days to harvest: ~105 days from planting out.

Frequently asked questions

When is the best time to plant sweet potatoes in New Jersey?

In New Jersey (mostly USDA zone 7a), sow sweet potatoes indoors around early March, transplant outdoors early May (after the last frost, mid-April), and harvest from mid-August. Sweet potatoes 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 New Jersey?

Most of New Jersey sits in USDA hardiness zone 7a, with the state spanning roughly 6a-7b from the northwest Highlands near High Point (zone 6a) to the Atlantic shore and inner harbor (zone 7b). The last spring frost averages mid-April and the first fall frost late October.

Can you grow sweet potatoes in New Jersey?

Yes. New Jersey's dominant zone 7a supports sweet potatoes — the key is timing. Sweet potatoes 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 New Jersey?

the northwest Highlands near High Point (zone 6a) runs roughly 1-2 weeks behind the state average; the Atlantic shore and inner harbor (zone 7b) can plant 1-2 weeks earlier.

What else can I plant in New Jersey 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.