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What Are Plant Zones Anyway?

Updated: Dec 22, 2022

You may have noticed tags of potted plants listing the plant zone and wondered what that meant. Or maybe you noticed the name of this website and that made you wonder what plant zones are. To put it simply, plant hardiness zones refer to how cold it gets in a specific area at its very coldest temperatures, determining what perennials can survive in that zone. Plant hardiness zones also play into how long or short that zone's growing season is.

Why do I Need to Know my Planting Zone?

Planting zones Canada map for finding out what planting zone you are in.
Plant Hardiness Zone Map

Knowing and understanding your specific hardiness zone for growing is especially important to those of us in cooler growing zones, as we have a much more challenging time than the warmer areas of earth growing vegetables that produce well in our short growing season. Having a successful vegetable garden in zone 3 may mean needing to start plants that take longer to grow (like peppers and tomatoes) indoors early in the spring. In Alberta Canada where I live, gardening zones can range right from zone 0 to zone 4. See the table below to determine what plant hardiness zone you fall in to.

When you purchase a perennial (it is meant to come back each year) it is important to know your gardening hardiness zone. ALWAYS check what zone a perennial is for prior to purchasing. Many times I have been at a store and picked up a tree, shrub or perennial flower only to look at the tag and see it labeled zone 5 or 6 (I live in hardiness zone 3). If I was to purchase and plant this it would likely not live through the winter! On the other hand, perennials zoned for 0 to 2 will do just fine in zone 3 as the lesser numbers refer to areas even colder than where I live! To figure out what plant hardiness zone you are in, all you need to know is how cold it gets at its coldest where you live.

Plant Hardiness Zone Temperature Chart

Here is a breakdown of each plant hardiness zone's lowest temperatures that you can use to determine your plant hardiness zone.

Zone From To 0 - 53.9⁰C (-65⁰F) 1 -51.1⁰C (-60⁰F) - 45.6⁰C (-50⁰F) 2 -45.6⁰C (-50⁰F) - 40⁰C (-40⁰F) 3 -40⁰C (-40⁰F) - 34.4⁰C (-30⁰F) 4 -34.4⁰C (-30⁰F) - 28.9⁰C (-20⁰F) 5 -28.9⁰C (-20⁰F) -23.3⁰C (-10⁰F) 6 -23.3⁰C (-10⁰F) -17.8⁰C (0⁰F) 7 -17.8⁰C (0⁰F) -12.2⁰C (10⁰F) 8 -12.2⁰C (10⁰F) -6.7⁰C (20⁰F) 9 -6.7⁰C (20⁰F) -1.1⁰C (30⁰F)

10 -1.1⁰C (30⁰F) +4.4⁰C (45⁰F) 11 +4.4⁰C (45⁰F) +10⁰C (50⁰F) 12 +10⁰C (50⁰F)

Now that you know what plant zones are and what hardiness zone you live in you can make sure you are buying plants suitable to your location and check out gardening tips specific to your growing zone.

Leave a comment letting me know what plant hardiness zone you are in and if this information was helpful to you!


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A map showing plant hardiness zones for north America, Canada and the Canadian provinces.

Words "what hardiness zone am I in" with onions and vegetables growing in a zone 3 garden.

Words "what are plant zones" with a zone 3 vegetable garden growing lettuce and carrots in raised beds.


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