Hardiness zones

Hardiness zones

Want to learn more about Climate hardiness zones

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Climate hardiness zones

A plant’s hardiness zone is based on it being planted in the ground - if you however decide to put the plant in a pot, this zone is no longer valid. Potted plants are a lot more sensitive to cold temperatures compared to plants in the ground.

Hardiness zones 1

Hardiness and potted plants

If you live in a hardiness zone that’s too cold for your plants, you need to overwinter them. If they are also potted, you need to take extra care so they won’t freeze during the colder months.

Planta will give you a lowest recommended temperature in which your plant will survive outside in a pot. If your site is too cold we will inform you of this.

However, keep in mind that this temperature is how much your plant can handle - and not the temperature it prefers. If you place your plant in this temperature, it will probably suffer a bit - it could, for example, lose its leaves and flowers, start drooping, and its leaves might turn yellow - but it should survive and recover once it’s placed in the recommended temperature again.

Hardiness zones 2

Hardiness zones explained

Your hardiness zone is based on where you live, and determines what plants you can grow in your area. A zone is defined by calculating the lowest mean temperature during a couple of winters.

Zone calculation example

If the minimum temperature during five different winters are the following:

  • Winter 1: -10 °C (14 °F)

  • Winter 2: - 12 °C (10,4 °F)

  • Winter 3: - 16 °C (3,2 °F)

  • Winter 4: -10 °C (14 °F)

  • Winter 5: -4 °C (24,8 °F)

The mean temperature would then be: In Celcius: ((-10) + (-12) + (-16) + (-10) + (-4))/5 = -10,4 °C In Fahrenheit: (14 + 10,4 + 3,2 + 14 + 24,8)/5 = 13.3 °F

Which would put you in hardiness zone: 8a

Hardiness zones 3

Zone 1a is the furthest to the north - hence being the coldest one, and Zone 13b is the hottest and situated in the south. Between each zone there’s about 10 degrees, which would make Zone 2 10 degrees warmer than Zone 1.