When to plant chinese cabbage (napa) in Tulsa, Oklahoma

March 10 – March 17

Transplant outdoors · typical Tulsa year

Climate 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. Transplant chinese cabbage (napa) outdoors 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.

Last spring freezeMarch 311-in-10 after Apr 15
First fall freezeNovember 41-in-10 before Oct 20
Frost-free season220 daysmedian at 32°F
Hard freeze, 28°Mar 17Nov 13kills even hardy greens
USDA zone7b5 to 10°F winter low not frost timing

The Tulsa year

Start seeds indoorsFeb 3 – Feb 17
Transplant outdoorsMar 10 – Mar 17
  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to Apr 15
Chinese Cabbage (Napa) in Tulsa · freeze context from Tulsa INTL AP, OK, 1991–2020 normals.

Every method, with its sources

Start seeds indoors

Feb 3 – Feb 17

Arkansas Extension requires transplants no older than "four to five weeks" at setting out, so indoor sowing is counted back 28–35 days from the cited transplant window, giving last spring frost minus 56 to minus 42 days. Anchored to the median last spring freeze (Mar 31). University of Arkansas System Division of Agriculture, Cooperative Extension Service · Clemson Cooperative Extension, Home & Garden Information Center · Clemson Cooperative Extension, Home & Garden Information Center

Transplant outdoors

Mar 10 – Mar 17

Arkansas Extension states "Transplant two to three weeks before the last frost-free date", giving last spring frost minus 21 to minus 14 days; Clemson's warning that spring-frosted seedlings bolt is a caution on the same window, not a competing interval. Anchored to the median last spring freeze (Mar 31). Clemson Cooperative Extension, Home & Garden Information Center · Clemson Cooperative Extension, Home & Garden Information Center

Variety assumption: Offsets assume spring-set transplants of the 45–72 day Napa and Michihili types tabulated by Arkansas Extension; no fall window is encoded because every fall rule found for napa is fixed-calendar ("early to midsummer", "July") rather than frost-anchored.

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.

This week, not a typical year:
Crop rule sources (3)

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