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Hi Folks,


Now that the fruit tree list has been made available for the sale, and because Liz and I were emailing about my information on Chill Hours, I thought it would be helpful to share a chart I made up on chill hours.  The valley proper is USDA 9b or Sunset Zone 13, but with respect to chill hours we are all over the place.  Anywhere from a little over 200 (some parts of Mesa) to a usual 900 (Queen Creek).  It makes a BIG difference if you do not select trees appropriate for your neighborhood - literally.  Encanto area can be 700 hours.  So attached is my PDF chart on chills hours detailed from 2004 to 2011.  I updated the chart with the last couple of years info from that which is in my booklet on the subject.


After we never got any fruit on one of our original peach trees we discovered we were in a much warmer location of the valley, even though we are away from the heat island affect.  So I went researching and had the assistance of a very nice gentleman with the Arizona Climate Data center and spent some considerable time compiling the information.


Select trees that are at or UNDER the chill hour averages for your neighborhood/area.


By the way for those of you new to growing fruit trees in the valley, citrus do not have a chill hour requirement.  And, if you are in a higher elevation to or in the valley, you can grow citrus successfully if there is identifiable Ironwood trees in your neck of the state.


Happy Shopping!



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Thank you for posting the chart! I had no idea we got so many chill hours in Maricopa!!! I see Fuji apples in my future. : )
Hi Becky,  Yes I think you are certainly in an area there that would support the Fuji or even gala, but check to make sure :-)

I'm going to take the chart to my MG class and see what they say. I found it hard to believe that Maricopa gets more chill hours than Carefree/Cave Creek. Their elevation is higher and whenever there are snow sprinkles, they are the ones who get it - yet Maricopa has almost twice the chill hours? It just doesn't make sense to me. I'm very curious now.


I am going to try a Fuji in my yard. On one of the other threads, someone in Phoenix (I think) posted that their Fuji is doing well and bearing fruit. Since our chill hours are higher than I thought, I'm pretty sure one would fruit out here.


I wonder if anyone has had real success with the new low chill cherries.


I spoke to the man in charge of the fruit orchard on the U of A farm out here, and I believe he said that they lost 3 out of the 4  cherry trees this summer. He suspects that even with the low chill requirements, they may not be able to take the heat. I have to say though, that their growing environment is horrible - just out in the field with nothing to shade or protect the trees. I don't think their budget runs to building a permanent shade structure for a trial tree and the wind would make short work of anything less. A yard environment offers much more protection.

Yes, we have been getting very mixed results with the Cherry trees.  In some yards they are flourishing and incredibly productive, but in other yards they don't make it past their first summer no mater what steps are taken to baby them along.  It really is still an experiment and I appreciate all the great info people are sharing here on the website!

Thanks, Catherine, for posting this fantastic data.  This must have taken you quite some time to compile!

It took a while :-)  Deane and I want to try the cherry trees and I saw they are on the list, so I'm pretty sure he is going to want to try them, as we both love cherries.  We started out with Deane the expert in trees and me the expert in everything else, but I've learned a lot about the fruit trees over the years, so it will be interesting to try.  :-)

Hi Becky,


On the chill hour issue with elevation, this may sound kind of reverse but as you go 'up' the slope in the valley the temperatures are warmer.  You have heard 'colder valley locations' and it is literally 'valley' or the bottom of the bowl here.  I suspect you are in a 'draining' area where cooling temperatures literally drain down into lower elevations.  You can experience it first hand during the cool months here when you drive through the reservation in the East Valley, it feels like the temperature drops at least 10 degrees, because the reservation is at a lower elevation.  Yuma is at about 100 something feet above sea level yet it has more chill hours than some of Mesa.  Several factors then influence just how many chilly nights a location has.


It also means that if you purchase a rated tree in a neighborhood that is not yours you may be disappointed because they are (or should be) stocking the trees they know do well in that local.


I would be interested in what you MG folks think of the chart.  You or they can build their information by going to the climate data site and check out each year for their location.  :-)

You're right, Catherine. I didn't think about cold air sinking. Duh. I think about it in my yard, but didn't think about it in the wider area, which is far more important.


As much as I love cherries, I doubt they could survive the heat and harsh wind out here. I suspect that they will do better in town where the wind is moderated by surrounding trees and buildings. It seems that they would benefit by the additional humidity and cooling of being surrounded by mature trees. I will be interested in hearing how they do in the next few years.


When I hear of trees that are thriving, I find myself becoming more and more interested in the immediate environment - how mature the neighborhood landscaping is, what the exposure is, exactly what and how much is planted around the tree, etc. I'm beginning to think that those factors will have at least as much impact on the success of the tree as whether it is planted in Mesa (lowest chill hours on the chart) or Maricopa (approx. triple Mesa's chill hours). These are the things that are most difficult to find out, but would probably be the most helpful for budding permaculturists.

Hi Becky,


You really are on to what you need.  One of the very first things I noticed in my trowel and error beginnings was the density or lack of it for the best growth of plants here in the desert.  It is not far away from what is called the "nurse" plant strategy of desert plants.  A seedling takes root under or near a large plant and grows up in the protective canopy of the existing plant reaching towards the sun, but with its roots and sides protected.  Saguaros grow that way and you know how large they get :-)


I tell people to look around their neighborhoods at established plantings to determine what IS actually growing in that neighborhood.  If you are out in the really rural areas, that might not be an option exactly, but someone else may have already attempted what you are doing.

Maricopa is such a new city that there isn't much in the way of mature landscaping to look at - and pretty much all there is to see is the basic landscapers installation package. It's kind of depressing how much alike everything looks. HOA rules forbid fruit/citrus in front yards and I don't even see many citrus trees planted in back yards.


My hope is that someday I'll have a yard that other people will want to look at and learn from. That will be awhile though.

I understand Becky.  You will - you have a quest :-)  On the HOAs they can be a pain.  I gave a lecture several years ago to a gardening group in the Power Ranch area and they are not allowed to grow tomatoes - in their back yards - dropped my jaw, but their choice to live there.

You are kidding! That is appalling! Incredible and very sad. I know there are different rules for people who have view fences, but still... Very hard to believe.

I read the HOA rules before we bought the house, but I know many people just don't take the time.


Catherine, I just went to the weather data page and I cannot tell you how impressed I am that you managed to make sense out of it and actually find what you/we wanted to know. Thank you so much!!!


If the world depended on me for knowledge, we'd still be rubbing sticks together to make fire.


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