White mustard

Sinapis alba

Fastest-establishing green manure — germinates in 3–4 days. Glucosinolates released when the green mass is incorporated act as a natural soil biofumigant.

Hardiness ratings

White mustard hardiness across the four zone systems
SystemRatingTemperature rangeHow to read it
USDA hardiness zone Zone 2–10 −45.6 °C to 4.4 °C Zones where it can be grown as an annual — not a frost-tolerance rating
RHS hardiness rating H7 down to −20 °C Plant needs at least this level of cold tolerance
Canadian plant hardiness zone Zone 2–9 −40 °C and warmer Zones where it can be grown as an annual — not a frost-tolerance rating
Australian (ANBG) zone Zone 1–6 −15 °C to 15 °C Zones where it can be grown as an annual — not a frost-tolerance rating

As a tender annual, White mustard doesn't overwinter — the zone range shows where the growing season supports it. See the RHS rating for its actual cold tolerance.

Growing notes

  • Not a nitrogen fixer — its value is establishment speed and biofumigation
  • Brassica family — do not precede a brassica food crop (cabbage, broccoli, kale) in rotation; clubroot risk
  • Excellent quick cover for vacant beds; terminate before flowering to prevent volunteers

Categories

Related plants

Cross-check White mustard against your zones

Reference

White mustard on Wikipedia