Q.Cover Crops
When should I plant a winter cover crop?
A.
Plant winter cover crops 6-8 weeks before your first expected hard freeze. In the Upper Midwest that's late August-early September; in the Mid-South September-October; in the Deep South October-November. Earlier plantings produce more biomass; later plantings still work but with reduced fall growth.
Frost-date pages give your specific first-frost window. Crop calendar pages cover species timing.