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When to plant Summer Squash

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 Summer Squash 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 May 13–May 27 Apr 14–Apr 28 Mar 3–Mar 17 –
Transplant outside May 13–May 27 Apr 14–Apr 28 Mar 3–Mar 17 –
Fall planting Not available Not available Not available –
Expected harvest Jun 12–Jul 16 May 14–Jun 17 Apr 2–May 6 –

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 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.

Summer squash goes outside one to three weeks after your last frost, whether direct-seeded or transplanted. Colorado State University Extension classifies it tender (Fact Sheet 7.212) but notes transplants should be delayed until frost potential is fully over, the same pattern as cucumber; Purdue Extension (HO-186-W) classifies summer squash very tender outright, a full tier stricter. This page keeps Colorado State's tender label but uses the later, one-to-three-week-after window that accounts for its own delay caveat.

Start seed indoors two to three weeks before your last frost if getting a head start rather than direct-seeding. Soil should read 60°F. Days to maturity run 30 to 50, roughly agreeing between Colorado State's 50 and NC State's 30 to 40 from transplant; Missouri Extension's stated 80 to 90 days is excluded from this range as an outlier that does not match summer squash's typically fast maturity, likely a different measurement convention in that table.

In a cold-winter climate, Colorado State's own delay caveat matters more for summer squash than the bare tender-tier rule suggests; a mild-winter climate reaches 60°F soil sooner and can seed or transplant correspondingly earlier under the same one-to-three-week rule.

Summer squash is sold both as seed for direct-sowing once soil is warm and as transplants in cell packs, with direct-seeding the more common route for this fast-growing vine once the delay caveat above has passed.

Frost hardiness

Tender. Damaged or killed by frost. Plant after the last frost date.

Minimum soil temperature

60°F

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

Days to maturity

30–50

Sourcing notes

Same tender-vs-very_tender disagreement as cucumber (CSU=tender with delayed transplant caveat; PURDUE=very_tender) - used CSU. DTM: CSU (50) and NCSU (30-40, from transplant) roughly agree; MOEXT's stated 80-90 days looks anomalous for summer squash and was excluded from the range (likely a different maturity convention in that table) - flagged, not used.

Related crops

Growing zones for this crop

Nurseries near these locations

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Sources