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jal_ut
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Posts: 7447
Joined: Sun Jan 18, 2009 10:20 pm
Location: Northern Utah Zone 5

Er, um, does this mean I can grow orange trees?
Ummm, Nope! I doubt if you can even grow a peach tree. :P

One never knows though, I have two small 3 year old peach trees growing. Even got one peach off one tree this year. It has been my experience in the past that a peach may grow here for a few years, but then we get one of those winters when the temperatures drop to minus 20 F and you can kiss it goodbye.

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digitS'
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Posts: 3932
Joined: Sun Sep 26, 2010 1:10 pm
Location: ID/WA! border

I wonder what has happened to Stella, James.

She was around here so regularly right thru April then . . .

. . .

Steve :?

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Albert_136
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Posts: 33
Joined: Thu Mar 23, 2017 1:51 pm
Location: Nevada (Sunset 2b)

I just go to Google and key in ~ USDA hardiness [zip code] ~ and my zone just appears, no longer any need for squinting at a map.

[Chrome might just take me there, I may not even need to go to Google, perhaps, ... ]

PaulF
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Posts: 913
Joined: Tue Nov 09, 2010 5:34 pm
Location: Brownville, Ne

Arbor Day Foundation has issued a new hardiness zone map a couple of years ago, NOAA, National Oceanic and Atmospheric Administration, will issue its maps very soon, and the USDA will be releasing another zone map in the near future. The USDA usually waits for a ten year period for new maps, but they say the weather patterns are changing faster than in the past. The USDA uses a thirty year average of nighttime lows as their base. It is more for what will and can live in an area year around rather than seasonal gardening.

What may change are start times for growing annuals and length of season for annuals. My zone has changed from 5B to 6A, but over the years last frost and first frost has given me a few more weeks of growing season. Gardeners always try to push the limits and get more time, so we just haven't noticed the change.

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Gary350
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Posts: 7421
Joined: Mon Mar 23, 2009 1:59 pm
Location: TN. 50 years of gardening experience.

What good is hardness zone? Map shows I am in zone 7a but that is wrong it almost never gets 0 to 5 degrees here. It is very rare to get below 17 degrees that puts me in zone 8a. But past 2 years have been exceptionally cold down to 6 degrees. 40 years ago it was down to -17 for about 2 weeks. I don't see that zone has anything to do with plants. What a person really needs to know is when is first frost and last frost. Our last frost is about April 15 to 20 and our first frost is about Oct 25 to Nov 7. Often we have crazy 80 degree weather in Feb for 1 or 2 weeks. People should learn their own weather pattern where they live zone means nothing. I have seen a cold freeze and frost May 15 that really screws up a garden 1 month after the typical last frost. Who ever made up zones must have been smoking some good weed.

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applestar
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Posts: 30543
Joined: Thu May 01, 2008 7:21 pm
Location: Zone 6, NJ (3/M)4/E ~ 10/M(11/B)

When gardening, it’s true that you absolutely need to know the approximate first and last average frost dates, and they are not directly related to Hardiness Zones, but Hardiness Zone is also relevant for other reasons.

Hardiness Zone is exactly what the name implies — it indicates “winter hardiness” and is intended to differentiate which plants tend to be able to survive the winter. There are annual differences and borderline plants need/can be helped by adding a little winter protection — mulching, covering, etc. it also helps to know because plants that will become rampant weeds could be planted where they are not winter hardy to enjoy during the growing season and be merely winter-killed. It is also a good idea to buy locally adapted nursery plants.

There are food crops that are considered fall-winter season in warmer winter areas that simply cannot be grown where the winter low temperatures get too low, but some clever people have figured out that it’s possible to grow them double-protected by covering with fleece under high tunnel.

I tend to think in terms of winter survival from the freeze, but there are also plants that NEED certain amounts of cold dormancy — so there are plants that will not survive or fruit where the Zone is higher/hotter than its Hardiness Zone range. e.g. Sugar Maples grow well 25 miles north of here but not here (same for White Paper Birch).


Knowing the local weather patterns is important as stated. Because the zones are marked in broad sweeps across the map, it’s also important to know the local mini-climate surrounding your garden — urban heat pockets due to hard scape and population density, slope of the land, forested vs unforested, waterways, even underlying geological influences can create local differences — this is also true of frost dates. e.g. My MIL lives 23 miles north of here, but her last spring frost is 2 weeks earlier, and plants that won’t survive the winter in my garden without extra protection can survive in her garden.

My area is close enough to the Pine Barrens where the deep sand actually creates effects that lower the local temperatur in a vast enough pocket to affect the weather and climate, so even though my own soil is clay, my garden is affected by the general Pine Barren’s weather effect. I have also noticed that the weather systems which typically move from southwest to northeast are affected at the Delaware River — so we don’t usually get the deep snow winter cover that could make the critical difference in overwintering survival of some plants (or extra rain in the summer for that matter).

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applestar
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Posts: 30543
Joined: Thu May 01, 2008 7:21 pm
Location: Zone 6, NJ (3/M)4/E ~ 10/M(11/B)

Jelitto Perennial Seed | Plant Hardiness Zones
https://www.jelitto.com/Plant+Informati ... ess+Zones/

imafan26
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Posts: 13993
Joined: Tue Jan 01, 2013 8:32 am
Location: Hawaii, zone 12a 587 ft elev.

This map has been around since 2012, but most of the seed packages and books are still using the old zonal map. It is good that it does cover more micro climates, but for most people it probably won't change that much about the way they garden. What I found to be more important than the zones are the temperature ranges. With the increases in global warming over the last 3 years, I might have to consider upping my zone based on temperature.

I have always looked for heat and disease resistance since that is what is needed to survive scorching temperatures. It means that some varieties that many of you grow, I could never grow anyway. But, some of you may have to consider growing more heat resistant crops as well.

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applestar
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Posts: 30543
Joined: Thu May 01, 2008 7:21 pm
Location: Zone 6, NJ (3/M)4/E ~ 10/M(11/B)

2023 USDA Plant Hardiness Zone Map | USDA Plant Hardiness Zone Map
https://planthardiness.ars.usda.gov/home

Image
All Plant Hardiness Zone Maps (PHZM) should serve as general guides for growing perennial plants. They are based on the average lowest temperatures, not the lowest ever. Zones in this edition of the USDA PHZM are based on 1991-2020 weather data. This does not represent the coldest it has ever been or ever will be in an area, but it simply is the average lowest winter temperatures for a given location for this 30-year span (1991-2020).

Consequently, growing plants at the extreme range of the coldest zone where they are adapted means that they could experience a year with a rare, extreme cold snap that lasts just a day or two, and plants that have thrived happily for several years could be lost.
Go to website link above for interactive state and regional maps and poster-printable files. Links to additional informative pages.

— eta —
As of 6am, the interactive map features are not working for me on the iPhone. But I was able to download 300dpi of my state map.

imafan26
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Posts: 13993
Joined: Tue Jan 01, 2013 8:32 am
Location: Hawaii, zone 12a 587 ft elev.

The map is the same for me in zone 12a. Zones 12 and 13 are specifically for Hawaii and Puerto Rico. There are however, micro climates in Hawaii because we literally live on a mountain top with the base of the mountain on the sea floor. The climates range from preglacial zones on top of Mauna Kea, to humid tropical zones where most people live, to temperate zones and to arid and semi-arid tropical savannah. The Big Island has the most climate variation because it is the youngest island, if you don't count Lo'ihi.

I like that the map is more interactive and you can put in your zip code to locate you zone instead of having to match the colors.

https://em.gohawaii.com/mtr40/images/hv ... index.html



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