When to plant hairy vetch in Oklahoma City, Oklahoma
September 18 – October 18
Fall planting · typical Oklahoma City yearClimate basis: NOAA station Oklahoma City Will Rogers AP, OK (USW00013967), 7 mi (12 km) from downtown Oklahoma City (ZCTA 73102 centroid), elevation 1285 ft, on the 1991–2020 climate normals. Plant hairy vetch for fall from approximately the dates above, anchored to the median first fall 32°F freeze (November 2). One year in ten still freezes after April 20.
The Oklahoma City year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to Apr 20
Every method, with its sources
Fall planting
Sep 18 – Oct 18Alabama Extension states an explicit frost-anchored range — plant hairy vetch 15 to 45 days before the killing frost — which encodes directly as 45 to 15 days ahead of the first fall freeze; UMass Extension's general cover-crop rule of about 30 days before the first expected frost falls inside that range, so the wider Alabama interval is used and no conflict needed resolving. Anchored to the median first fall freeze (Nov 2). Alabama Cooperative Extension System · UMass Amherst Center for Agriculture, Food, and the Environment
Start seeds indoors
Not calculatedThe cited extension guides do not time an indoor seed-starting window for this crop.
Transplant outdoors
Not calculatedThe cited extension guides do not time an outdoor transplanting window for this crop.
Direct-sow outdoors
Not calculatedThe cited extension guides do not time direct sowing for this crop.
Variety assumption: Assumes seeding for overwintering and spring nitrogen, commonly drilled or broadcast in a mix with winter rye.
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)
- Alabama Cooperative Extension System: Cover Crops: Legumes (accessed 2026-07-25)"Plant hairy vetch 15 to 45 days before the killing frost."
- UMass Amherst Center for Agriculture, Food, and the Environment: Cover Crops — growing tips (accessed 2026-07-25)"As a general rule, cover crops should be planted about 30 days before the first expected frost date."