Winter wheat phenology (SEP → AUG). Sow/emergence in fall → tillering → dormancy through winter (~108 days, often under snow) → growth resumes/jointing → boot → heading → dough stages → harvest in early summer.

• Max vegetation signal: heading through mature (APR–JUN) — that’s when NDVI peaks.
• Best imaging windows: greening-up (to separate wheat from other species) and peak cover (for biomass).