JodoGarden

The "from/to" chart shows minimum temperatures for each zone. Zones are broken down into two parts, A and B.. the A of each zone being slightly colder than the B within 5 degrees. The temperature ranges within each zone just shows the coldest known temperature and then a 5 degree range where that zone "resides". In other words zone 10a for example resides within 30F and 35F (technically it would be 30F - 34.99F)... 10b resides within 35F and 40F and so on. The most important thing to look at in a zone is the lowest temperature, not so much the temperature range that defines it. The lowest temperature is what actually defines the zone regardless of the temperature range. It's more of a microclimate thing. Some people say things like "a warm zone 10a" for example... meaning it might only get down to 34 degrees and not 30 degrees... so that temperature range makes sense and maybe someday the zones will get broken down into even smaller sub-zones.

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