How to Choose Plants for Your Zone Part 2

Across the country, from 1974 to 1995, weather stations recorded their maximum daily temperatures. Each participating weather station had to provide information for a twelve year period at least, to be included in the data.

The American Horticultural Society (AHS) then used this information to develop the Heat-Zone Map which was released in 1997. There are twelve zones in this map and they are categorized by the number of days that area is subjected to temperatures above 86 degrees Fahrenheit, (also known as ‘heat days’).

This temperature was chosen because 86 degrees is when plants begin to experience damage from heat. The lower the Zone number, the lower the amount of heat days experienced. For example, Alaska falls in Zone 1 which means it has less than one heat day per year. Zone 12 experiences a significant period of the year in heat days – more than 210 of them!

So now plants are coded for their ability to withstand heat and their hardiness. Each coded plant will have four numbers which relate to their heat and hardiness zone relativity. These numbers will give you a good indication if the plant you want is suitable for the area you live in.

Always remember that the coding is reliant on the plant getting sufficient water. If the plant is affected by dry conditions they may not thrive as well as expected. You will also need to ensure your plants have adequate oxygen, light and air movement.

Again, their tolerance to heat may not be as expected if these are not managed sufficiently. And don’t forget your soil pH! If you want your plants to thrive as suggested by the heat and hardiness zone maps, you must take care of these variables.

So now you need to find out what zone, for heat and hardiness, you live in. Once you know this information you can begin to select the right plants for your garden.

Tags: Gardening Tips