JungleSeeds

JungleSeeds&Gardens - Specialists in Exotic Seeds & Plants

USA Zone Classification

 

As most of you know the USA use a zone classification for plant cold hardiness, please remember that these only give a rough guide to hardiness in the UK. The USA has higher summer temperatures to harden plants and often only short spells of frost rather than long cold dark damp winters in the UK. However you may find this useful as we are approximately in the range 7a to 8b in England.

 USDA Zone  Temperature Range
         1   Below -50 F 
(below -45.6C)
        2a  -50 to -45 F 
(-42.8 to -45.5 C) 
        2b  -45 to -40 F 
(-40.0 to -42.7 C) 
        3a  -40 to -35 F 
(-37.3 to -39.9 C) 
        3b  -35 to -30 F 
(-34.5 to -37.2 C) 
        4a  -30 to -25 F 
(-31.7 to -34.4 C) 
        4b  -25 to -20 F 
(-28.9 to -31.6 C) 
        5a  -20 to -15 F 
(-26.2 to -28.8 C) 
        5b  -15 to -10 F
(-23.4 to -26.1 C) 
        6a  -10 to -5 F
(-20.6 to -23.3 C) 
        6b  -5 to 0 F 
(-17.8 to -20.5 C) 
        7a  0 to 5 F 
(-15.0 to -17.7 C) 
        7b  5 to 10 F 
(-12.3 to -14.9 C) 
        8a  10 to 15 F 
(-9.5 to -12.2 C) 
        8b  15 to 20 F 
(-6.7 to -9.4 C) 
        9a  20 to 25 F 
(-3.9 to -6.6 C) 
        9b  25 to 30 F 
(-1.2 to -3.8 C) 
       10a  30 to 35 F 
(1.6 to -1.1 C) 
       10b  35 to 40 F 
(4.4 to 1.7 C) 
        11  above 40 F 
(above 4.5 C)