When to plant hairy vetch in Detroit, Michigan
September 16 – October 16
Fall planting · typical Detroit yearClimate basis: NOAA station Detroit City AP, MI (USW00014822), 6 mi (9 km) from downtown Detroit (ZCTA 48226 centroid), elevation 626 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 (October 31). One year in ten still freezes after May 6.
The Detroit year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to May 6
Every method, with its sources
Fall planting
Sep 16 – Oct 16Alabama 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 (Oct 31). 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."