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When to plant Watermelon

Computed from land-grant Extension planting-window rules (cited below), localized to real ZIP-level median frost dates, not a single national guess. These are national-generic rules by hardiness class; individual state Extension offices layer their own regional adjustment on top (earlier in the Deep South, later in the Upper Midwest). Enter your ZIP for your own dates, or read the four representative locations below.

Planting windows and crop timing here are computed from USDA/NOAA climate data and the university extension sources cited below, not a site visit or soil test. Treat this as a starting point: local conditions vary, and a local nursery or extension office can advise on your exact site. See our full Disclaimer.

Representative timing, by climate band

When to plant Watermelon in four US climates

Each column is the most nursery-dense location in our directory within that USDA zone band, computed from that location's own real median frost dates, not a made-up example.

Stage Zones 1-5 (cold winters)
Fort Plain, NY 		Zones 6-7 (temperate)
McMinnville, TN 		Zones 8-9 (warm)
Apopka, FL 		Zones 10-13 (hot, frost rare or absent)
Loxahatchee, FL
Start seed indoors Apr 15–Apr 22 Mar 17–Mar 24 Feb 3–Feb 10 –
Direct-sow outside Not available Not available Not available –
Transplant outside May 20–Jun 3 Apr 21–May 5 Mar 10–Mar 24 –
Fall planting Not available Not available Not available –
Expected harvest Jul 21–Aug 27 Jun 22–Jul 29 May 11–Jun 17 –

Zones 10-13 (hot, frost rare or absent) (Loxahatchee, FL): Frost is rare here (about 359 frost-free days a year); most years see little or no hard freeze. This is a very tender crop. In climates like this one, tender and very-tender crops typically go in before the hottest months arrive, not on a frost-relative schedule.

Watermelon transplants two to four weeks after your last frost. Colorado State University Extension and Purdue Extension both classify it very tender (Fact Sheet 7.212; HO-186-W) and agree exactly on a 60°F minimum soil temperature at transplant.

Start seed indoors two to three weeks before your last frost for a head start, though direct-seeding once soil is warm enough is also common for this crop. Days to maturity split by counting convention: NC State's 62-to-72-day figure is counted from transplant, while Colorado State's 85 days is counted from direct seed; the combined range is reported with that difference flagged rather than merged into one number. Missouri Extension's watermelon table gives variety and fruit-weight information but no explicit days-to-maturity figure, so it contributes to the planting-date guidance here but not to this range.

As a very-tender crop, a cold-winter climate needs the full two-to-four-week buffer past frost before soil is reliably at 60°F; a mild-winter climate applies the same buffer against an earlier frost date and reaches that soil temperature sooner.

Watermelon is sold both as seed for direct-sowing and as transplants in cell packs for a head start; given how much space a mature vine needs, direct-seeding once soil is genuinely warm is the more common choice over transplanting.

Frost hardiness

Very tender. Killed by even light frost or cold soil. Plant well after the last frost date, once soil has warmed.

Minimum soil temperature

60°F

For direct sowing/germination, where an Extension source stated it.

Days to maturity

62–85

Sourcing notes

From transplant. CSU and PURDUE agree very_tender and agree exactly on 60F min soil temp. DTM: NCSU's 62-72 is from transplant; CSU's 85 is from direct seed - combined range, convention flagged. MOEXT's watermelon table gives varieties/weights but no explicit days figure, so it wasn't used for DTM (still used for its planting-date table).

Related crops

Growing zones for this crop

Nurseries near these locations

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Sources