WHY STUDY A CLIMATE/GARDENING ZONE CHART? WHY IS IT IMPORTANT TO KNOW YOUR CLIMATE ZONES?
With spring comes planning and planting, and the most important question is “What can I Plant?”
Before you even consider buying, study your zone chart and find out your plant zone number. Do you live in the northern, southern, eastern, or western part of North America? Are your winters harsh? Are your summers scorching hot? What plants/trees will withstand your type of weather?
Most plant tags feature a zone number to indicate the plant’s hardiness, that is, its ability to survive cerrtain conditions. If that number is 3, then it means that plant will do well in all zones from 3 upwards.
If the number is 5, and you live in zone 3, then if you buy that plant, it will need extra protection in zones 4, 3, and will probably not survive in zones 2 and 1. The idea is to check the number on the plant tag to see if it can survive in your climate zone.
The Continental North America zone chart is divided into 11 zones:
Zone: Temperature F (Fahrenheit) — Temperature C (Celsius)
Zone 1 is below -50F or below -46C (certain parts of Northern
Zone 2 is -50 to -40F or -46 to -40C (Northern Canada)
Zone 3 is -40 to -30F or -40 to -34C
Zone 4 is -30 to -20F or -34 to -29C
Zone 5 is -20 to -10F or – 29 to -23C
Zone 6 is -10 to 0F or – 23 to -18C
Zone 7 is 0 to 10F or -18 to -12C
Zone 8 is +10 to+20F or -12 to -7C
Zone 9 is +20 to 30F or -7 to -1C
Zone 10 is +30 to 40F or -1 to +4C
Zone 11 is +40 to +50F or +4 to+10C (Southernmost tip of US and
If you are in Quebec City, for example, (Zone 4) you would look for plants that are listed as Zone 4, 3, 2, or 1. If they can survive in zone 1, they can survive in the warmer zone of 4. If you pick a plant listed as zone 5, it might be difficult to have it overwinter outside in a zone 4 area.
Most plants can be grown in a wide range of zones. Some plants such as perennials, biennials, and bulbs are hardy only in certain zones. But annuals (plants that grow for only one season) grow in any zone as long as they are given the proper amounts of water and sunlight but will not survive the winter if left outside.
The zones on this chart represent the average minimum temperatures in different areas. The zones actually blend into each other, and within each zone there are microclimates that can be colder or milder.
The lower the number on the plant tag, the hardier the plant.
So before you even look at plants, get a planting zones map from your local plant nursery and find out what zone you live in. It helps to know what zone you live in so you can buy plants that will do well for you.
Please note: Since the weather seems to be changing because of global warming, my climate zone map may at some point need to be modified. Therefore, if you get an updated planting zones map, just be aware that some of the above temperatures might be different.
Also within each zone are pockets which are warmer than the rest of the zone area. This means that you may be able to overwinter certain plants which in the rest of the zone would not survive.
Here’s a 17 seconds visual from YouTube on the different climate zones with 1 being the coldest area and 10 the hottest: