What is my equivalent US gardening zone?

[Laura Corin]

So much information on the Web is US-based, it would help if I could work this out.  

 

We are 5 miles from the sea, our last frost is in mid May and our first frosts are usually in October, we are a long way North (only a few hours of true darkness in high summer), our mean summer high temp is 18-20 degrees C (mid 60s F), our mean daily minimum in winter is 0-2 degrees C (low to mid thirties F) and our rainfall is 600 to 800mm (24 to 30") per annum.  We usually only have snow on the ground for a few days each winter.  

 

Would the Pacific Northwest be our nearest comparator?

 

Thanks

 

L

[Amira]

I'm inclined to think you might be similar to Zone 5 from the Sunset climate zones.  Does this description sound like what your climate is like?

 

 

"Mild ocean air moderates Zone 5, allowing it to produce some of the finest rhododendrons, Japanese maples, and rock garden plants anywhere.Heaths and heathers thrive in sandy soils along the coast and inland, and katsura trees reach their prime, rarely scorching as they may inland. It’s also fine country for native woodland ferns, trilliums, piggyback plants, vine maples, and dogwoods. Summer highs run between 65 and 70°F (18 and 21°C) along the coast, and between 70 and 75°F (21 and 24°C) inland and around Puget Sound. Such mild temperatures favor leaf vegetables, which are slow to bolt, and flowering ornamentals like begonias. Steady breezes and lower temperatures, especially along the coast,make windbreaks and warm microclimates critical for heat-loving plants.

 

"Average January minimum temperatures range from 33 to 41°F (1 to 5°C),with annual lows averaging a few degrees colder, and 10-year extremes ranging from 20 to 6°F (–7 to –14°C). Some locations (Coupeville, Raymond, Long Beach, Tillamook, Newport) get 10-year lows between 6° and 10°F (-14° and –12°C), but much of the region, especially along the Oregon coast, is mild enough to let gardeners get away with growing plants like Washingtonia robusta and hardy forms of Agave americana. Big freezes do considerable damage when they come very early or very late. And while these occasional disasters clear the slate of most borderline plants, they should not serve as a general gauge of plant hardiness here. Though the growing season averages between 200 and 250 days, heat accumulation is low, and warm-season vegetables develop slowly."

 

From this site.

[trulycrabby]

I would think it's more similar to one of the Alaskan or Canadian climates because you are farther north. Alaska has a rainforest and the southeast part of the state is more temperate.

[Laura Corin]

I'm inclined to think you might be similar to Zone 5 from the Sunset climate zones.  Does this description sound like what your climate is like?

 

Yes it does as far as temperatures/conditions are concerned.  I don't think our growing season is that long though, just because of being further north.  That sounds like a good place to start though.

 

Thanks

 

L

[Amira]

Yes it does as far as temperatures/conditions are concerned.  I don't think our growing season is that long though, just because of being further north.  That sounds like a good place to start though.

 

Thanks

 

L

I was thinking your growing season was probably shorter.  I was able to grow tomatoes in Seattle, and it seems like you've said you can't.  I think zone 4 is a little colder than you are, although the growing season is probably more accurate.

[Laura Corin]

I would think it's more similar to one of the Alaskan or Canadian climates because you are farther north. Alaska has a rainforest and the southeast part of the state is more temperate.

 

I had a look and, while the growing season is more likely to be right, the Alaskan temperatures are too cold in winter.  Sunset Zone 5 with a mental note about season length is probably closest.  I have to do this in the UK too - gardening advice tends to be centred on England, so you have to adjust for Scotland.

 

Thanks

 

L

[Cosmos]

The USDA hardiness zones are limited in usefulness because they only take into account the lowest winter temperature, in other words -- what is going to be able to survive that amount of cold? It doesn't take into account length of growing season or snow cover or your maximum temperature or lots of other things that affect what will actually grow.

 

That said, this wikipedia page suggests that Scotland will match a hardiness zone of between 7 and 9. There's a chart partway down the page.

[Laura Corin]

The USDA hardiness zones are limited in usefulness because they only take into account the lowest winter temperature, in other words -- what is going to be able to survive that amount of cold? It doesn't take into account length of growing season or snow cover or your maximum temperature or lots of other things that affect what will actually grow.

 

That said, this wikipedia page suggests that Scotland will match a hardiness zone of between 7 and 9. There's a chart partway down the page.

 

Thanks - we are solidly in the 8 zone on that map.  So now I have Sunset 5 or USDA 8, with that mental note about season length.

 

Thanks, everyone.

 

L

[Amira]

The USDA hardiness zones are limited in usefulness because they only take into account the lowest winter temperature, in other words -- what is going to be able to survive that amount of cold? It doesn't take into account length of growing season or snow cover or your maximum temperature or lots of other things that affect what will actually grow.

 

That said, this wikipedia page suggests that Scotland will match a hardiness zone of between 7 and 9. There's a chart partway down the page.

 

 

This is why I like the Sunset zones better.  They're still not perfect, but they're not just about minimum winter temperatures.