What's My Zone? Gardening Tips, Capital Nursery, Sacramento, Elk Grove, Citrus Heights, California

What's my Zone?

This is often a very confusing question. The "Zone" references mentioned here, unless otherwise described, are the USDA plant Zones.

These are indicated on a color map that show the approximate minimum temperatures recorded in a geographical region. For this reason it is commonly called the Hardiness map. Click on the map below for a closeup.

Even though a substantial amount of time and energy has gone into the accuracy and production of the map, it cannot be considered foolproof.

For starters, no consideration is given towards maximum temperatures or humidity. By excluding these factors, Tucson, Arizona is in the same zone as Tampa, Florida. Citrus may thrive in these areas, but Saguaro cactus clearly would be inappropriate for gulf coast Florida.

Temperature Minimums
Zone 1 =	below -50F
Zone 2 =	-50F/-40F
Zone 3 =	-40F/-30F
Zone 4 =	-30F/-20F
Zone 5 =	-20F/-10F
Zone 6 =	-10F/ 0F
Zone 7 =	0 F/+10F
Zone 8 =	+10F/+20F
Zone 9 =	+20F/+30F
Zone 10 =	+30F/+40F
Zone 11 =	+40F
F = Fahrenheit

Regional microclimates can influence the zone number for small areas. A southward facing parcel on a gentle slope in zone 6 may have less harsh conditions than a valley floor area of zone 7. Record-setting climatic conditions are always changing and the zone boundaries must change accordingly.

New maps appear about every ten years as new low temperatures are recorded.

Back to Gardening Tips Contents