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When to plant Radish

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 Radish 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 Not available Not available Not available –
Direct-sow outside Mar 25–Apr 22 Feb 24–Mar 24 Jan 13–Feb 10 –
Transplant outside Not available Not available Not available –
Fall planting Aug 11–Sep 8 Sep 4–Oct 2 Nov 3–Dec 1 –
Expected harvest Apr 14–May 27 Mar 16–Apr 28 Feb 2–Mar 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 hardy crop. In climates like this one, hardy and semi-hardy crops typically go in during the cooler months (fall through late winter), not on a frost-relative schedule.

Radish goes into the ground two to six weeks before your last frost. Colorado State University Extension's hardy rule (Fact Sheet 7.212) gives two to four weeks before frost; Purdue Extension (HO-186-W) gives four to six weeks before for the same hardy tier, the same gap between the two sources seen across most hardy crops in this table. Both windows are published here rather than merged.

Soil should read 40°F at seeding; Colorado State and Purdue agree exactly. Days to maturity run 20 to 35, the fastest crop on this entire page, combining NC State's 20 to 25, Missouri Extension's 25 to 35, and Colorado State's 30.

Radish also takes a fall planting, four to eight weeks before your first fall frost, per Purdue's explicit list. Because radish matures so quickly and is genuinely hardy, both a cold-winter and a mild-winter climate can fit several sowings into a single spring, and again into fall, rather than treating either window as a single planting date.

Radish is seed-only at the nursery, sold cheaply and in bulk given how fast it matures, for both the spring and fall windows above.

Frost hardiness

Hardy. Tolerates hard frost. Can go in the ground before the last frost date.

Minimum soil temperature

40°F

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

Days to maturity

20–35

Sourcing notes

CSU's hardy window (2-4wk before) and PURDUE's hardy window (4-6wk before) both apply to radish; used the union and flagged the boundary difference (consistent across most hardy crops in this dataset - see report). CSU/PURDUE soil temp agree at 40F. DTM: NCSU 20-25, MOEXT 25-35, CSU 30 - combined range. Fall figure per PURDUE's explicit list.

Related crops

Growing zones for this crop

Nurseries near these locations

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Sources