This is mine.Thanks,Tom.
Now all I need is more heat in the Summer. Brady

Below 45 model: 2062
Between 45 and 32 model: 1253
Utah model: 1731

For my part of San Jose

Below 45 model: 413
Between 45 and 32 model: 384
Utah model: 421

I'm worried about Utah & Van cherries, I think they are 700 hrs. Put in a Lapins this year, that is more in line I guess.

I had around 400 across the board, 10 miles inland San Diego. I usually get around 300 so it was a cooler than normal year.

Below 45 model: 413
Between 45 and 32 model: 412
Utah model: 401

My Blenheim Apricot is blooming erratically even with that much chill. It is only rated at 400 or less. It must have something to do with the 70-80 degree warm-ups we get in the middle of winter.

This post was edited by econ0003 on Sun, Mar 10, 13 at 3:01

Mission Viejo, southern California

9 miles inland from the coast

Below 45 model: 426
Between 45 and 32 model: 420
Utah model: 365

North Houston (depressing for chill needy)

Below 45 model: 471
Between 45 and 32 model: 409
Utah model: -474

Thanks everyone for the numbers. It's nice to see what everyone is dealing with. And thanks to Tom for an easy way to look at some numbers.

Melike in San Jose: I think I'm having a chilling issue on cherries in my greenhouse...for the last 8 years. I'm kinda slow on the uptake because I could solve this issue and hope to next year. I don't have Utah Giant, 800 hrs, but do have Van, 700hrs, and Lapins 500 or less. Neither Van nor Lapins have done well in the GH. The two varieties that have done best for me have been Rainier and Sonata. In general the self fertile varieties (Sweetheart, Skeena, Selah, Sandra Rose) have done the worst. Lapins not much better. Sonata by far the best self fertile variety.

Tom:

I think what messed up my apricots outdoors this year was a couple weeks of really warm weather in the second half of January. This after our only real chilling weather mid Dec to mid Jan. I think that warm spell was enough to send the cots towards bloom and rendered any chilling after mid January ineffective.

So that leads to my other point here. Tom's wonderful aid calculates chill hrs Nov 1 to Febr 28. But depending on many factors part of that chilling, especially the later part, may be totally ineffective for part or all of ones fruits.

Fruit-

Wouldn't I still be adding on since my trees are still very dormant? I've got 8 inches of snow on the ground and 2 feet of frost in the soil.

frank:

Yes in a northern climate you could accumulate chilling starting in Sept or Oct and run until things start to warm in spring. The coastal NE and the PNW have 6 months of chilling.

Numbers I get for La Crosse:

Below 45 model: 1942
Between 45 and 32 model: 440
Utah model: 330

For some reason it won't let me use the airport closest to my house...but this one is only about 5 miles away....

I think the regional numbers are interesting.

Frank in WI is too cold in mid winter to get high Utah numbers. But add on Oct and March and he will get plenty.

Doglips down by Houston is so warm that the Utah model ceases to be useful. Some low chill plants still do well with the alternating warmth and short cool spells.

Brady in western WA has nearly nonstop chilling all winter. Temperatures there stay 30s and 40s day and night.

The desert areas like west Texas and the inland SW are too cold at night and too warm by day. We get some cold but it's not very effective.

Hopefully no one is jumping to any drastic conclusions or making draconian changes based on these numbers. I really don't trust the results from this calculator. Here is what nearby stations are reporting regardless of browser:
Station 1:
Below 45 model: 134
Between 45 and 32 model: 134
Utah model: -1452

Station 2:
Below 45 model: 0
Between 45 and 32 model: 0
Utah model: 0

Station 3:
Below 45 model: 253
Between 45 and 32 model: 253
Utah model: 198

I've had good chill this year with everything setting fruit (so far) as expected including Royal apricot.

Scottsdale, Arizona (Phoenix). Golf all year around and a major vacation spot in the winter.

2012

Below 45 model: 658
Between 45 and 32 model: 606
Utah model: 399

2011
Below 45 model: 601
Between 45 and 32 model: 591
Utah model: 463

This may explain how I've been able to grow pears and apples pretty well in my patch of desert. We have traditionally thought that we get less than 400 hours worth of yearly chill on average here in Phoenix.

AJBB:

Or, it could be that apples and pears fruit just fine on less than 400 chilling hours (a conclusion I've come to).

There's so many excellent low-chill stonefruit to choose from that I've pretty much given up any chilling-hour worries.

franktank,
The airports use a different URL format than the other stations on wunderground so it doesn't work.

mrclint,
The calculator is only as accurate as the data reported by the weather stations. A high percentage of weather stations on wunderground are missing large amounts of data. I would check the daily records of any weather station before using it for a calculation.
If you get zero that typically means the station name entered did not match(letters case sensitive for some weather stations) or there is no data for that year.

This post was edited by econ0003 on Sun, Mar 10, 13 at 20:27

Applenut:

What rootstock is that apple in the pictures above on? Ur pruning it central leader, or? How many years old? I need to figure out how to efficiently space my fruit trees. Sorry for the irrelevance.

Appreciate it,
Joe

Joe- it's on M111 and is third leaf. It's at a pre-school and doesn't get a lot of love, pruning once a year to central leader where the goal is to get skinny, drooping branches. They're spaced at 10 feet and the variety is Dixie Red Delight, simply outstanding in our climate, a hard, dense, sugary-tart late winter keeper.

Joe:

There is nothing about an apple tree in southern CA with very low chilling that will help you in Ohio. The trees grow differently. I would hope that Applenut has better trees and fruit than what's on that tree. The fruit, besides being crab apple size is very sparse. And the tree looks like it's never been pruned. I'm not sure you can do better than that down there but you can in OH.

Sorry applenut but all the trees I've seen you post so far look the same, very ragged and small sparse fruit.

econ0003,
How did the calculator come up with "-1452" Utah hours? How is it possible to have a negative number here? If the numbers on wunderground are not reliable, then the calculator is of no value.

Below 45 model: 134
Between 45 and 32 model: 134
Utah model: -1452

Sorry for the ragged tree photos fruitnut, and yes, the young tree is at a preschool and never gets pruned. But we do get much better apples and crops than that such as these Fujis, some of the best I've ever tasted.

However, even if the trees and crops were all like the photo, is that a reason for people not to grow them and settle for the miserable apples we have in the store?

mrclint,

There are plenty of reliable stations on wunderground. I would recommend looking at the daily records to determine which ones are reliable. Like you mentioned performing a calculation is worthless if data is missing.

With the Utah model negative chill is accumulated above 60 degrees. Here is how the Utah model works:
1 hour below 34ðF = 0.0 chill unit
1 hour 35 - 36ðF = 0.5 chill units
1 hour 37 - 48ðF = 1.0 chill units
1 hour 49 - 54ðF = 0.5 chill units
1 hour 55 - 60ðF = 0.0 chill units
1 hour 61 - 65ðF = -0.5 chill units
1 hour >65ðF = -1.0 chill units

Dave Wilson article that describes three common chilling models

This post was edited by econ0003 on Mon, Mar 11, 13 at 0:15

Applenut, nice response and you are right on all counts. You can grow apples in your environment and even in the tropics. It's just that you haven't convinced me that the trees and fruit are as good as northern grown. Maybe if I figure out how to do it myself in a somewhat less demanding environment than yours I will be a believer.

Maybe someday I'll come around. It was a lot easier growing apples up north and maybe I'm too old to learn new tricks. But I'll keep trying.

Thanks for being nice about my scepticism .

Applenut,

I've read your ebooks and your articles on growing apples in low chill environments and the tropics. I've also grown them myself in less traditional places like the Sonoran and Mojave deserts. I agree with you -- some select apple varieties, including a few Northern varieties, can grow well in low chill places. However, in all due respect, the vast majority of apple trees do not do well in these same environs and often produce lots of bare wood and tiny fruit, if they even fruit at all. That's why the go-to varieties in Phoenix are Anna and Golden Dorsett and not Northern Spy, Liberty, or Macintosh.

econ0003, in my case the chill hours have no practical application. Royal apricot is said to require 400hrs and I've got fruit set with 134hrs. The whole thing is a bit of a time waster. Fruit trees are either time tested for a given area or they aren't.

Applenut, I appreciate folks like you that push the envelope, but Fuji is a great low-chill apple. And I get very nice organic apples here in local stores and Farmer's Markets. I'm not sure I understand your point in this case.

Fruitnut, I thought that was a cheap shot. I can't remember ever seeing a picture of one of your trees in full view. And cheap shots like that from a renowned member makes people less apt to post their photos in the future. Looks can be deceiving, and a fuzzy photo in a school yard gives no indication of fruit quality. A school yard tree is lucky to be alive and fruiting at all.

The Utah model uses negative values for temperatures above 61 degrees.

Fruitnut- You are right; some of the apples here are much better than northern-grown. We've traveled up and down New England and Virginia and know what the good stuff is, and the best of our hot-climate apples hold their own just fine against anyting we've tasted in our travels. The key is finding those varieties well-suited beyond the usual Anna and Dorsett Golden (which are indeed incredible when well-grown) that prefer a long, hot season, just like the English seek out varieties that prefer the gloom. I'll put our Wickson Crabs (photo) up against anyting we tasted in our travels, as I will our Bramleys. Macintosh is horrible here but Empire is wonderful; you just can't tell until you try it.

How many apple industries have been built around a single apple variety that that "sings" in a certain locality, like Gravenstein in Sonoma or Lurared in Medina, Texas? The only way to ever find them though is to actually grow them and see what happens rather than listening to everyone who says it can't be done. To this day Fuji is still listed in catalogs as zone 8 and 600 chilling hours.

I have found indeed that early intervention is needed for training an apple tree to be productive in the heat, otherwise it has tall, spindly, vertical branches with lots of blind wood. I believe a lot of suitable varieties have been written off when proper training would have solved a mostof the problems.

I was asking applenut about the rootstock/spacing of his fruit tree merely to help me plan on th spacing for my fruit trees... I understand it different climates,etc. Just needed a rough estimate. Thanks. Now that picture of the apple above with the white dots on it, i heard it was caused from a calcium deficiency.. It's hard to believe.. I would think is was a micronutrient... Calcium seems adequate in soils, unlike micronutrients, maybe it's just me.. Thanks
Joe

mrclint,

I respect your opinion and I totally agree that the whole chill hour thing is questionable. The chill rating they give each cultivar seems questionable. The number can vary quite a bit depending on who you ask. The models all say something different. If you are only interested in the tried and true varieties for a specific area then there is really no need to track chill hours.

On the other hand if you want to experiment with cultivars that haven't been tested well in a certain area then tracking chill hours is just one way to try and assess the risk of growing a particular cultivar for that area.

This is far from a science. These models are utterly rudimentary.
Different species in all likelihood have different chill point temperatures. Relative humidity probably is a factor along with the health of the tree. Micro climates within a property I would guess could make a big difference.
There are probably 2-3 dozen other factors that no one realizes,....yet.
As Econ alluded to, use the experience of others. If you are experimenting, uses the stated chill hours of the plant and your area as a guideline, not as gospel.

Joe; no, the little white dots are lenticles, little gas vents, typical of the variety. The attached show some Wicksons where this is less pronounced. With our alkali soils calcium deficiency isn't much of a problem (we get iron chlorosis instead).

Applenut:

What intrigues me about your climate is the possibility of harvesting apples in December to February. I know Axel in Santa Cruz area does that. Unfortunately in Texas it gets too cold to hold apples on the tree that long. I hold my Pink Lady as long as possible, usually Nov, but they are a mere shell of the fabulous fruit I harvested 500 miles north of here with twice the chilling.

Maybe someday I'll figure it out. Right now my thinking is that I need to reduce the summer heat load by planting grass, putting up shade cloth, or both. Do you have any experience with anything along those lines?

I have many varieties that are pushing the chill hour "envelope". I am becoming a 1-man research facility for coastal southern california (9 linear miles from ocean). Hopefully I can garner some good data for y'all over the coming years. Here is a link again to what I am growing:

http://www.mediafire.com/?6tk520xln00w8tw

I have a 4-in-1 cherry in a 15 gal container as my "cherry test stand". Lapins, Stella, Lambert and Bing. If chill hours are any indication, i should get a few Lapins and Stella next year. Bing or Lambert would be a surprise.

A few pleasant observations:

Bloomed heavy:
Green Gage (jefferson) plum
Dapple Dandy pluot
Bonita Peach

Bloomed mediocre:
Cot n Candy pluot
Emerald Drop aprium
Autumn Rosa plum

I have many more that have bloomed, but the chill hours are not really a surprise (all

ahajmano,
That is quite a list of fruit trees.The self-fertile Bing may be a Lapins. Lapins Cherry

My Splash Pluot has proven to be very low chill. I get a large crop regardless of weather in San Diego. Dapple Dandy looks like the same(a lot of fruit setting on 4th year). Heavy bloom on 1yr Flavor king pluot and Mediocre bloom on 1yr Emerald Drop pluot.Not much luck with Apriums. Just a few fruit each year.

Belowe 45: 254
Between 45 & 32: 253
Utah Model: -648

I don't really under stand the Utah model. What's its purpose? If these numbers are even relatively close they still fall way short of my 450-550 chill hour rabbiteyes. That being said they are flowering and leafing out fine. Sometimes I wonder how they come up with chill hour requirements. Maybe if I did receive the correct amount of chill hours I would see better growth than what I'm seeing? I don't know, they seem to be growing great!

Fruitnut; yes, this is Sundowner (Cripp's-Two, comes off patent this November) around the second week of December, and Lady Williams is ready the first week of January. Both are pretty decent but need a loooong, hot season.

I purposefully do not utilize any shade measures as I want to find the varieties that can take 110+ temps and still be good, and it is amazing the range that do. Of course Sundowner from down under is heat proof, but so is Bramley from England which ripens smack in the middle of our worst monsoon heat (113F and humid) in September and is still crisp, juicy, and sweet-tart. Honeycrisp comes through it amazingly well also, better than anything I've tasted in the store, which isn't saying much as they're absolutely horrible from the market- way too green.

this is me in foothills north of los angeles:

Below 45 model: 554
Between 45 and 32 model: 540
Utah model: 614

The idea behind the Utah model is that the plant is starting to come out of dormancy and resetting, the same way we don't accumulate chill hours year after year. I would guess that Utah model should say, when you hit zero, stop subtracting and stay at zero, then go positive again as needed.
I suspect that the Utah Model probably works better in certain areas of the country than others. I'm guessing......Utah. My numbers are like yours, negative. So the Utah model may not be relavant for the deep south. This is based on a observation of two for one season that could be an aberration. Hardly scientific.
I think all of these models are, not a joke, but an extreme simplification of a highly complex process.
It is just like when you look at hurricane forecast models, there are 10 different models with many going in the same direction, and a few all over the place. It doesn't mean that the model that is way out there, is a bad model, it just didn't hold for that scenario. The next time it could be a perfect match. Hurricane models are heavily studied and would take up 5-10 sheets of paper to write out. We are using a model that can be described in 25 characters or less. The model we are using may be less accurate than the "if it is cold out, stomp your foot, if your foot gets really sore, you'll get fruit", model.
The stated chill hours of your blueberries may well be wrong, I doubt that person that created those numbers was a climatologist and did exhaustive studies on the rating. You also may not get the yields had the chill hours been above the rated hours.

Station 1
Below 45 model: 174
Between 45 and 32 model: 172
Utah model: -1147

Station 2 (400-700 feet away from station 1)

Below 45 model: 207
Between 45 and 32 model: 199
Utah model: -1213

Station 3 (about same distance away from station 1)

Below 45 model: 214
Between 45 and 32 model: 199
Utah model: -1121

Interesting tool but I also have doubts about the accuracy.

Here is what I get from AgroClimate chill hour one.

http://www.agroclimate.org/tools/ChillAccum/
(central Florida Dover station)

Accumulated period from Oct 1 to Mar 11:
This season: 246 hours
Last season: 134 hours
Historic average: 293 hours

I can't say yet on results of fruit trees as they are only been in ground for one year. However low-chill cherry (mini-royal or royal lee, don't remember which is which off of top of my head) had 3-4 flowers. And that was before we got additional 40-60 chill hours last couple of weeks.

Surprisingly I actually got couple of cherries, no idea if they will fall-off or not because no other cherries had any blooms to pollinate. (self-pollinating royals? lol)

That Utah model does seem crazy, it's use is very questionable in the south. Unless we make transition graphs from + to - and the resulting blooms (which will take years to collect data.)

The Utah model isn't intended for climates like south Texas or Florida. After all it was developed in Utah with long cold winters and high chill crops.

The low chill crops grown in South Texas apparently aren't affected by the warm temperatures mid winter that are accumulating negative Utah chill hrs. The only useful model there is the below 45F. If you see numbers in TX that what you are looking at.

The highest Utah hrs I found in Texas was 650 at Amarillo in far north Texas. The below 45F there was 1450. They get a lot of cold. The Utah model helps my understanding some at that location and I grew fruit there 30 years. The large difference between the two models tells me the cold up there isn't too effective. Mostly too cold at night but some days above 60F where negative Utah chill hrs accumulate.

HappyBallz,
The numbers you posted are pretty consistent. Each weather station temperature sensor has some tolerance for error which would cause a slight variation in chill accumulation. Micro-climates or a station going down for a day or two could also explain small differences.

The AgroClimate station has accumulated an extra 1.5 months of data. Therefore I would expect a higher number there. The getchill website is using the same chill period as UC Davis. Accumulation is done from 11/1-2/28. If you are in an area that does not have the same chill period then it may not be useful to you.

This post was edited by econ0003 on Tue, Mar 12, 13 at 17:52

Utah is high desert, low humidity. That may be a factor that improves accuracy of that model.

Well now I understand the Utah model better, thanks Doglips, but want to question a few things about blues imparticular. To really get a gauge on what I'm seeing compared to my northern brothers who recieve the stated chill requirements for a certain variety of blues, would have to be growing them and prunning the same with the same amount of fruit buds and pollination. From what I've read about rabbiteyes a 60-70% fruit set is considered a good crop. Would that be a plant that is not pruned to thin fruit buds? Would thinning fruit buds increase that % to be concidered good fruitset. Is pollination the limiting factor? Does every flower contain the proper components to form fruit if pollinated? If chill hours aren't meet do the flower buds not develop right but still flower out, then just abort? Will the lack of chill hours effect the plants more when they are considered mature? Will it shorten the life span of the plants? Should I start a new thread???

I am certain microclimate is a major factor that is hard to fit into these models.

My property does not get a lot of winter sun, so my nectarine trees break a coupe weeks later than my sister's (same variety) which is a 3 minute walk away. I also live in a depression, which would tend to accumulate frosty air, compared with a south facing slope, where the earth will warm up and shed cool air. Even within this little 0.2 acre, there are several radically different microclimates.

Got a high-chill variety? Plant it in a frost pocket or place that doesn't get much winter sun. If you live in a low-chill zone, you're going to have plenty of summer sun to make up for it.

Not a blueberry expert, Blue.
Chill hours are often equated to not getting enough sleep or rest. Tired and don't perform well.
I don't know what you are reading but I would assume that the 60 to 70% fruit set means 60 to 70% of the flowers form fruit that makes it to maturity. So, yes, i would assume that is referring to an unpruned plant. i wouldn't thin unless you appear to have too much fruit on a given limb. Some plants are good about shedding fruit that it knows it can't carry to maturity and others don't. I don't know bluebs.
It is an imperfect world, many flowers don't have the right stuff, again I don't know bluebs.
I have limited space and a You Pick Blueberry Farm down the street, so I will probably never be an expert at growing them, eating is another story.
I'd recommend a new thread.

@applenut:

>It's at a pre-school and doesn't get a lot of love, pruning once a year to central leader where the goal is to get skinny, drooping branches.

Why that goal? I hope people don't mind the threadjack. I am awfully curious!

The tree looks very happy to me, despite the odd shape.

This year, our chill hours apparently came later in the season than normal. We had some really cold weather in February. Pluots and apricots which sometimes start blooming in late January didn't start blooming until mid-late February. Cultivars which do not normally bloom with them have joined in for a more compressed bloom season.

Saw a bee actually working Flavor Supreme blossoms. A good sign, since this variety is not very attractive to bees. It's a new tree, quite close to others blooming at the same time.

Below 45 model: 566
Between 45 and 32 model: 545
Utah model: 522

And, you can probably add about 20 more ch to my equation, as I was late in getting my weather station up and online. Carolyn is describing my situation exactly. My pluots are very late to blossom. All pears are still dormant, but I do finally see a couple of leaves starting to push out this week on a couple of my earlier pears. My Peacotum has only now pushed out 2 blossoms. But, good new for my Minnie Royal and Royal Lee, they are better synced, just took two weeks for the Minnie Royal to really open up the blossoms, and some of the earliest Royal Lee blossoms are turning into little cherries. So, I should have my first decent crop of Minnie Royal/Royal Lee cherries this year. I will be building a netting cage for both of them this year, and am taking extensive measures to keep snails out of my trees this year. They were worse than the birds for ruining my stone fruit. I also had quite a few blossoms on both my pleurries I planted in January, but the danged Burgundy plum was much slower to wake up, so no significant cross pollination occurred, so highly unlikely I'll get any pleurries this year, so disappointed. They are interesting looking trees, though. the leaves are very unique.

Patty S.

Patty:

I'm amazed at how much more effective chilling is in your climate than mine. I've got 248 more hours below 45F but 158 less hours Utah.

My thinking is the But I think the Utah model tells you what you have for high chilling plants like regular sweet cherries and high chill apricots.

522 Utah doesn't cover all the bases but it's close.

Well, probably because we have a large number of nighttime hours between 36 and 46 degrees. In the winter out here, it's not unusual to have temps in the high forties at sunset, but never get below 32 degrees due to being so close to the coast. So, we don't get the negative hours below 32 degrees, but we get chilly fast in the evening, in the winter, and stay between 36 and 46 degrees until sunrise the next morning. We have a very, very unusual microclimate here in the hills of Vista (and the hills of Fallbrook) that make it ideal for growing just about anything. That's why we have the highest concentration of commercial growers out here. I am surrounded by either commercial nurseries or orchards, and it's due to our very interesting microclimate.

Patty S.

NilaJones- I bumbed the subject to a new thread.

NilaJones- I bumbed the subject to a new thread.