Gardening By Zone - USDA 9b / Sunset Zone 13

Dear Folks,

Gardening By Zone - Why It Matters!

Living in the desert and loving to garden here is my passion, but also my inspiration to help others garden successfully.  Much of it is based on my/our trowel and error experiences of what worked and how.

It is a serious challenge when a would-be gardener moves here from New Jersey or Minnesota  – where the gardening season is 90 to 120/140 days.  Even Southern Californians have trouble understanding our climate.  They are used to gardening year-round, but get caught up with the heat issue.

In 4-season climates like the Midwest or northeast, you basically looked to your local nursery for when to buy and plant things.

While some of that is true here in the desert, it is also true that nurseries here:  1) carry plants grown elsewhere, and 2) carry plants that people request, which are not always seasonally appropriate.  This is particularly true of the chain nurseries, although they do try to have regional nursery selections available.

I'm not knocking the nurseries - it is a business fact of life - your customer wants a tomato plant in late September or Early October - you give them the plants, even though the production going into fall and winter is either severely limited or non-existent.  Tomatoes like their feet warm and need long, warm/hot all day sunshine to thrive.

So it becomes really important to understand what zone we are in, and to make use of planting data that I or some of the organizations in the Valley (like the County Extension Service) provide.

It is vitally important to understand our zone because ordering plants outside of Arizona may give you very poor results.

For example:  For years Starks Brothers Nurseries, who are known for the quality of their fruit trees, listed the Valley as USDA Zone 8 (I believe they have since corrected this).

The problem became apparent when folks ordered fruit trees (we had a very early experience with this) that their catalogs "said" would grow here, and we watched the trees die, quickly, and never fruit.  Their customer service was spectacular –  they replaced the trees and even offered to give us a 3rd round of replacements, but it was apparent they simply would not thrive here - it is a matter of chill hours.

Deciduous fruit trees that will grow and produce here in the valley are desert adapted bred specifically for our climate.

The Zones

We are in USDA Zone 9b and Sunset Magazine Zone 13.

The Sunset Zone 13 is the more important of the two as Sunset had researched the details of how elevation, microclimates and cold impacts regional gardening.  In Zone 13 we can literally garden year round, with a climate which is 'subtropical' (specifically “subtropical hot desert) and very like the Mediterranean (Jerusalem) and other parts of the world (Alice Springs, Australia – except Alice Springs’ year is reversed from ours).

Move into Sunset Zone 12 and your gardening is reduced to about 300 days of the year instead of 360.

Successful Gardening

Based on the number of gardening days here, the specifics of seed germination, amount of day light hours, and soil and air temperature, gardening successfully here in the desert is about when to plant.

Fruit Trees, for example, do best if planted in the cool fall (October-ish), which allows the roots to get good and strong before summer temperature impact the soil surface temperature.

Chill hours are important for choosing deciduous fruit trees here.  Choose one with more chill hours than your backyard has, and you will likely never get fruit except in those rare winters when we have multiple days of below 30 temperatures - say every 5 or so years!

Even in the Valley here we have microclimates which can create a range of chill hours and frost from as low as 250 hours (some parts of Mesa) to 900 hours (Queen Creek).

It is important to understand the chill hours of your backyard.

Other perennials such as herbs like rosemary, thyme, oregano etc. also do best if planted in the fall.  They will not do much growing the first year because of the limited winter day light hours.  But the plant is busy putting down healthy, deep roots.

Varieties of vegetables and other herbs are divided into cool and warm weather categories.

Cool weather varieties are the root crops (beet, carrot, radish etc.), the cabbage family, all the greens, sugar peas, and herbs such as cilantro and dill.

Warm weather varieties are the beloved tomato, along with eggplant, peppers, tomatillos and herbs such as basil, chives and epazote.

What all this means.

If you get a case of spring fever in early March and start planting brussels sprouts, lettuce, tomatoes and basil, the first two may come up but will stall or die and the last two will do some growing, but should have been planted at the beginning of February, to take advantage of the warming soil, but not the galloping temperatures.

Basil is always the surprise for new-to-the-desert gardener.  In the middle of July, basil planted at the right time in late winter (early February), can turn into a 3 x 3 foot (or bigger) bush!  It loves the heat, but it has to have a deep root system to thrive.

Sunset Zone 13 is not just for the Valley of the Sun.  Below are other cities which are in Zone 13 and gardeners there can benefit from our resources.  (I also, for the sake of ease of finding cities, listed both the Phoenix Metropolitan area as well as the Yuma Metropolitan area.)

My Wall Calendar for gardening in this zone gives month-by-month planting information along with monthly to-do helper tips.

The Maricopa County Extension Service has helpful links for the backyard gardener.

The Valley Permaculture Alliance offers a free question and answer forum and classes for a low fee.

These listed cities and communities (I couldn't resist adding the "ghost towns" as I figure some intrepid souls may be giving a homestead a go there) are based on Sunset's Zone Maps.

Folks who live in the Valley here and have friends or relatives in any of the listed cities, can reliably share gardening tips and information.  I personally consider sharing the love of gardening one of the best connections to family and friends.

I did my best to be accurate here.  If I made a mistake whether including one or excluding one, please let me know.

Phoenix Metropolitan Area:
Apache Junction
Avondale
Buckeye
Carefree
Cave Creek
Chandler
El Mirage
Fountain Hills
Gilbert
Glendale
Goodyear
Guadalupe
Litchfield Park
Mesa
Paradise Valley
Peoria
Queen Creek
San Tan Valley
Scottsdale
Sun City
Sun City West
Sun Lakes
Surprise
Tempe
Tolleson
Youngtown

Yuma, Arizona area Cities and Communities which may also be in Sunset Zone 13
Arizona City (Ghost Town)
Avenue B and C
Aztec
Buckshot
Castle Dome Landing (Ghost Town)
Castle Dome (Ghost Town)
Cocopah Indian Reservation
Colorado City (Ghost Town)
Dateland
Dome (Ghost Town)
Donovan Estates
El Prado Estates
Fillibusters Camp (Ghost Town)
Fort Yuma Indian Reservation
Fortuna (Ghost Town)
Fortuna Foothills
Gadsden
Gila City (Ghost Town)
Hyder (Ghost Town)
Kofa (Ghost Town)
La Laguna (Ghost Town)
Martinez Lake
Mission Camp (Ghost Town)
Mohawk
Orange Grove Mobile Manor
Owl (Ghost Town)
Padre Ranchitos
Pedrick's (Ghost Town)
Polaris (Ghost Town)
Rancho Mesa Verde
Roll
San Luis
Somerton
Tacna
Wall Lane
Wellton
Wellton Hills
Yuma

Other Cities in Sunset Zone 13
Alamorio, California
Bagdad, California
Bard, California
Blythe, California
Bonds Corner, California
Borrego, California
Brawley, California
Cadiz, California
Calexico, California
Calipatria, California
Citrus View, California
Coachella, California
Cross Roads, California
Curlew, California
Danby, California
Date City, California
Desert Springs, California
Desert Center, California
Dixeland, California
Earp, California
Edgar, California
El Centro, California.
Fuller, California
Havasu Lake, California
Herber, California
Holtville, California
Imperial, California
Indian Wells, California
Indio, California.
Mecca, California
Meloland, California
Moss, California
Needles, California
Niland, California
Ocotillo, California
Orita, California
Palm Desert, California
Palm Springs, California
Palo Verde, California
Parker Dam, California
Plaster City, California
Salton, California
San Isidro, California
Sandia, California
Seeley, California
Vidal, California
Westmoreland, California
Wiest, California
Winterhaven, California

I hope you find this information helpful.  I hope everyone grows some or more of their own food.  The reward is far more than excellent food.  The process of nurturing plants to healthy growth, flower and fruit is almost unequal to the overall sense of satisfaction.


There is peace within a garden,
a peace so deep and calm
That when the heart is troubled
it’s like a soothing balm
There’s life within a garden,
a life that still goes on
Filling empty places
when older plants have gone
There’s glory in the garden
every time of year
Spring, summer, autumn, winter,
to fill the heart with cheer
So ever tend your garden,
its beauty to increase
For in it you’ll find solace,
and in it you’ll find peace.

– Rosamond, Lady Langham

I was truly blessed to have a copy of the book in which this poem appeared from Lady Langham's family.  A true reminder of the pleasures of gardening.


-- Catherine, The Herb Lady

http://www.herbs2u.net/