If you’re new to gardening, then you’ll hear a lot about hardiness zones, but there’s more to it than that.
Hardiness zone *only* tells you about how cold you can expect your coldest temperatures in winter to be, but people try to use it for a lot more than that. Here’s one example for the US:
Another thing that’s important to know if you want to grow perennials, particularly things like gooseberries and apples, is how many chill hours (iirc, hours between 45f and freezing) you get, which is shown in this next map:
I’m guessing North Dakota is in that little bubble because they spend so much of winter below freezing, which doesn’t count toward chill hours.
A third consideration, which comes in handy when someone who’s used to Texas thinks you should be able to grow papayas near Seattle because it’s also zone 8 for hardiness, is the heat zone you’re in. Heat zone measures how many days above 85f a location got, historically. Either last year was a huge anomaly (let’s hope) or this desperately needs to be updated:
When you combine these three, it gives you a better idea of what you can grow, and what will thrive in your area.
By the way, here’s a Chill hours chart from One Green World nursery:
If you’re new to gardening, then you’ll hear a lot about hardiness zones, but there’s more to it than that.
Hardiness zone *only* tells you about how cold you can expect your coldest temperatures in winter to be, but people try to use it for a lot more than that. Here’s one example for the US:
Another thing that’s important to know if you want to grow perennials, particularly things like gooseberries and apples, is how many chill hours (iirc, hours between 45f and freezing) you get, which is shown in this next map:
I’m guessing North Dakota is in that little bubble because they spend so much of winter below freezing, which doesn’t count toward chill hours.
A third consideration, which comes in handy when someone who’s used to Texas thinks you should be able to grow papayas near Seattle because it’s also zone 8 for hardiness, is the heat zone you’re in. Heat zone measures how many days above 85f a location got, historically. Either last year was a huge anomaly (let’s hope) or this desperately needs to be updated:
When you combine these three, it gives you a better idea of what you can grow, and what will thrive in your area.
By the way, here’s a Chill hours chart from One Green World nursery:
Fruit Tree Chill Hours Chart
Almond: 400-600
Walnut: 800-100
Filbert (Hazelnut): 800-1300
Chestnut: 300-500
Pistachio: 550-800
————————————–
Apple: 700-1000 (Low chill varieties between 200-500)
Apricot: 500-800
Peach: 600-1000 (low chill varieties between 300-500)
Nectarine: 100-500
Asian Pear: 400-500
European Pear: 600-800
Japanese Plum: 500-900
European Plum: 700-1000
Pluot: 400-800 (Low chill varieties between 200-300)
