Why Login?Logging in will give you access to features such as:
  • Saving Favorites
  • Entering Contests
  • Adding Plants
  • Adding Photos

Register for a free account!

* - Indicates required fields Username:* First name: Last name: Email address:* Password:* Confirm password:* Country: Region: State: Zip: Birthday:* Gender*    Male    Female Income*   per year Keep in touch with P. Allen Smith's weekly e-newsletter.    Yes! I would like to receive the email newsletter.    No thanks!

Hardiness Zone Map

Print Friendly Version

-40 to -30º F
(-39.9 to -34.5º C)

-30 to -20º F
(-34.4 to -28.9º C)

-20 to -10º F
(-28.8 to -23.4º C)

-10 to 0º F
(-23.3 to -17.8º C)

0 to 10º F
(17.7 to 12.3º C)

10 to 20º F
(-12.2 to -6.7º C)

20 to 30º F
(-6.6 to 1.2º C)

30 to 40º F
(-1.1 to 4.4º C)

One of the most common questions I receive from fellow gardeners is "What hardiness zone do I live in and what the heck is a hardiness zone anyway?"

Well, it is an important question in helping decide what plants to use in your garden. You see, all plants are cold tolerant to a certain temperature and unless you plan on treating a plant like an annual, meaning that it will only live one growing season, you need to know if it will survive through the winters in your area. This is especially important with big-ticket items like trees, shrubs and roses.

To help gardeners with this information the U.S. Department of Agriculture developed the Plant Hardiness Zone Map. This map divides the continent of North America into 11 regions or zones. The average coldest temperature for that region determines each zone. The coldest zone is zone 1, which includes areas such as the extreme northern parts of Canada, parts of the Yukon Territory, and the Alaskan interior. Average lows are about – minus 50 degrees F in zone 1 (now that’s cold!). Zone 11 is the warmest zone with average low temperatures being 40 degrees F. The other zones fall in between these extremes. What this means is that if you buy a plant that is cold tolerant to zone 7 and you live in zone 5, that plant is not going to make it through the winter.

In addition to the Plant Hardiness Zone Map, many people also reference the American Horticulture Society's Heat Zone Map, which helps you determine if a plant will survive the summer weather in your area. The AHS explains the map this way:

"The 12 zones of the map indicate the average number of days each year that a given region experiences "heat days"-temperatures over 86 degrees (30 degrees Celsius). That is the point at which plants begin suffering physiological damage from heat. The zones range from Zone 1 (less than one heat day) to Zone 12 (more than 210 heat days)."

You can learn more about the Plant Hardiness Zone Map and the Heat Zone Map on the AHS's website, www.ahs.org. Click on "Gardening Q and A."

Write a comment

  • Required fields are marked with *.

If you have trouble reading the code, click on the code itself to generate a new random code.
 
Showing comments 1 to 10 of 12 | Next | Last
Comment
raised bed gardening
Doug Decker
Reply #12 on : Sat January 02, 2010, 10:06:47
I plan to build a raised bed garden this spring so I can raise vegetables. In my internet search I've run across "click-together componenets", vinyl, lapped corners and various others. My thought was to use bales of straw, but they would decompose and need to be replaced. What is the best method that is cheap? How deep should it be for root vegetables? Any help you can give me would be greatly appreciated. I am unemployed.
Comment
Hardiness Zone Map
Derrick Evans
Reply #11 on : Sun October 04, 2009, 22:23:38
Thank you so much for this helpful guide!
As a new master gardener this guide will be helpful to show my costomers.
Comment
Bahamas Hardiness Zone
Deena Patterson
Reply #10 on : Sun September 20, 2009, 00:10:46
What the heck zone is the Bahamas in?...I would appreciate any help I can get.
Comment
Zone
Tanya
Reply #9 on : Thu July 23, 2009, 15:32:47
What zone am I in. I live in Kaufman, Texas right outside of Dallas. 75142
Comment
What zone am I in?
Ron
Reply #8 on : Fri June 19, 2009, 12:18:40
My zip code is 13303, what zone does that fall in? Thank you for your help!
Comment
Hard to determine which zone
moom
Reply #7 on : Sat May 16, 2009, 08:04:33
I am in the high desert in California. Very hot summer and very cold winters. What is my zone? Please help.
Comment
Pruning Bradford Pear Trees
Nancy
Reply #6 on : Wed May 13, 2009, 12:09:01
I live in the lower Part of Hardiness Zone 7
Zip 39443
Would it be risky to prune some large lower limbs of a Bradfor Pear Tree this late in the season? Thanks!
Comment
Hardiness zone
Yvonne Leever
Reply #5 on : Sun March 29, 2009, 16:55:31
What is the planting/hardiness zone for Rough and Ready, Ca? My zip code is 95975.
Comment
Zone for Sutter Creek, CA
Peggy Allard
Reply #4 on : Fri January 16, 2009, 16:35:34
What is the planting zone for Sutter Creek, CA? Zip code 95685.
Comment
year around shrubs zip code 62801
Ann Shaver
Reply #3 on : Sat May 03, 2008, 09:52:34
I need to plant shrubs to hide a generator, what can i plant that will keep foliage year round?
Showing comments 1 to 10 of 12 | Next | Last

Rate It!

3/5 stars (1686 votes)


Share It!

Share |
Add To Favorites
Why Login?Logging in will give you access to features such as:
  • Saving Favorites
  • Entering Contests
  • Adding Plants
  • Adding Photos

Sign Up For Newsletter