USDA Plant Hardiness Zone
USDA Plant Hardiness Zone means the 11 regions or planting zones as defined by a 10 degree Fahrenheit difference in the average annual minimum temperature.
7 CFR § 760.1502
The following definitions apply to this subpart. The definitions in 718.2 and 1400.3 of this title also apply, except where they conflict with the definitions in this section. In the event of conflict, the definitions in this section apply.