New Jersey planting calendar

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

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

Watermelon planting timetable for New Jersey

Stage	When in New Jersey	Anchor
Start seeds indoors	mid-March (March 18)	4 weeks before the last frost (mid-April)
Transplant outside	late April (April 29)	14 days after the last frost (mid-April)
First harvest (estimate)	mid-July (July 18)	~80 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 watermelon 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 — watermelon stall in cold ground even after the air warms, so don't rush them out.

Start seeds indoors 3–5 weeks before last frost; transplant only after all frost danger is gone and soil is consistently 65–70 °F (18–21 °C) — cold soil causes stunted growth and root rot. Days to harvest range 70–90 from transplant depending on variety (icebox types ~70 days, full-size ~85–90 days). In zones 9–11 direct sowing is practical; in zones 3–5 choose early-maturing varieties (≤80 days) to beat first fall frost.

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 — 8+ hours direct.
Soil temperature for germination: 21–35 °C (70–95 °F).
Spacing: 36–48 inches (90–120 cm) in-row; 72–96 inches (180–240 cm) between rows between plants.
Days to harvest: ~80 days from planting out.

Frequently asked questions

When is the best time to plant watermelon in New Jersey?

In New Jersey (mostly USDA zone 7a), sow watermelon indoors around mid-March, transplant outdoors late April (after the last frost, mid-April), and harvest from mid-July. Watermelon 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 watermelon in New Jersey?

Yes. New Jersey's dominant zone 7a supports watermelon — the key is timing. Watermelon 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.