When to plant radishes in Tulsa, Oklahoma
March 1 – March 15
Direct-sow outdoors · typical Tulsa yearClimate basis: NOAA station Tulsa INTL AP, OK (USW00013968), 7 mi (11 km) from downtown Tulsa (ZCTA 74103 centroid), elevation 650 ft, on the 1991–2020 climate normals. Direct-sow radishes from approximately the dates above, anchored to the median last spring 32°F freeze (March 31). One year in ten still freezes after April 15.
The Tulsa year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to Apr 15
Every method, with its sources
Direct-sow outdoors
Mar 1 – Mar 15Purdue: hardy — 4–6 weeks before the last frost; Penn State's earliest sowing Apr 1 (−30 days) is the later start and is used. Anchored to the median last spring freeze (Mar 31). Penn State Extension (York County Master Gardeners) · Purdue University Extension
Fall planting
Sep 9 – Oct 7Purdue Table 2: plant fall radishes at least 4–8 weeks before the first fall frost. Anchored to the median first fall freeze (Nov 4). Purdue University Extension
Variety assumption: Assumes a spring type (about 25–35 days; Penn State lists 30).
These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.
Crop rule sources (2)
- Penn State Extension (York County Master Gardeners): Vegetable Seed Planting Guide (accessed 2026-07-24)Earliest/latest sowing dates for a May 1 last-frost / Oct 1 first-frost baseline; offsets derived by date difference from May 1. Also days-to-maturity figures.
- Purdue University Extension: Indiana Vegetable Planting Calendar (HO-186-W) (accessed 2026-07-24)Hardiness classes: hardy = plant 4-6 wk before last spring frost; semi-hardy = 2-4 wk before; tender = after average last frost; very tender = at least 2 wk after. Table 2: fall planting at least 4-8 wk before first fall frost.