There are parts of central and Southern CA where one can have citrus happily fruiting next to apples, peaches, apricots, and plums.
For any of you in those areas, how does that work? Looking at climate data for some of these places, (those warm enough for citrus to survive) I can’t imagine you get enough chill hours per conventional wisdom!
The climate of CA is changing. Less fog in winter and less chilling. But look at the temperatures in winter. That tells you all you need to know about why all those crops work. It doesn’t fall much below freezing and doesn’t get too warm in winter. In the central valleys the entire winter can be between mid 20s and mid 60s, a 40F range. Here in Texas we can have a 60F change in 36 hrs.
They have lots of winter days with lows in the 30s and highs in the 50s. That’s good chilling weather for apples and stonefruit and actually nice even for citrus in winter.
Summers are lots of sun and heat with nearly zero rain. With irrigation that’s good fruit weather.
Fruitnut nailed it. I have enough chill hours to grow the stone fruit I want, but have tons of sweet citrus inground. I.e. the perfect climate. No snow, or hard freezes ever. But plenty of heat for heat loving crops.
Los Angeles should be able to have all of those, some apples are actually grown in Chile, South America so they don’t all require a long cold winter. Yucaipa, California is a place that a lot of pick your own apple orchards exist, so they must have an ideal climate for growing them, it’s located in the Greater Los Angeles area.
I think @Calron, @JoeReal and @fruitgrower have the best weather in the world for growing fruit. The only fruit they cannot grow are some of the really frost tender tropical fruits.
My location in San Jose used to be too I think. I’ve seen firsthand my chill hours reduce from around 1000 to 700 in the last 6-7 years. Which means I can’t grow some high chill varieties reliably. I get enough heat though.
I really don’t know why because the way the trees flower or get fruits is always changing unexpectedly. I think the main difference between inland southern California and the east coast is that the air is not humid so the night will cool down a little even in during the hot summer. As long as there is enough irrigation the trees will survive. I am in the 10a zone about 30 miles east of LA. In a radius about 30 miles from my area the types of fruit growing vary a lot, depend on the microclimate of the place. It is true that the majority of the houses will have one or more citrus trees. Orange county is where you see a lot of Asian fruit trees like longan, cherimoya, persimmon and jujube, but the stone fruits used to be bland or not reliable because there was not enough heat during summer. However, the weather is getting hotter the last two years so we will see how it affects the fruits. My area is not supposed to be good for anything, but my house is up on the hillside with unobstructed wind from the freeway afar so it is much cooler at night than the house on the next street down. We wrap the reflective windshield sunshade around the containers of all potted plants to keep the roots cool year round, and pine needles as mulching on the top. This year the Santa Rosa plum only had some flowers in June when everything else are done forming fruitlets. It was lucky that I got a Weeping Santa Rosa up north last October and it flowered early. Everything got pollinated from some trees after that. All the plums, pluots, nectarines and peaches trees with a chill hours of 500 or less are loaded, even the 6-700 hrs Emerald Beaut plum trees. However, I don’t know why there is no Fuji apple or asian pears. They were always full of fruits every year before.
I do know that zones are not zones. Zone 9b in CA gets more chill than zone 9b in FL IIRC. Zone 8b in WA gets more chill than zone 8B in MS…
Absolutely.
Below 45 Model: 871 chill hours
Between 45 and 32 Model: 842 chill hours
Here in Livermore we have tons of heat and dry for 8 months of the year, yet have chilly winters. Really Ideal!
Zones aren’t about chill hours, they’re about minimum temperatures. Trees that go dormant and tolerate freezing aren’t super zone dependent, assuming they’re hardy. Citrus is a lot tougher, can’t let it freeze, which is why it’s pretty much zone 9+.
California never gets really cold (except in the mountains- we have the tallest mountain in the lower 48!), the ocean and ocean-related weather moderate our temperatures. Virtually all year long, the prevailing winds blow from the chilly Pacific onshore, and the ocean never gets anywhere near freezing (unless you’re swimming in it).
Chill hours are generally defined as cold but not below freezing, which describes most of our winter weather. Most of the state has plenty of winter nights in the 30s and 40s, but aside from the deserts and high elevations, hard freezes are fairly rare, and a hard freeze for us is the low 20s, not 0s or negatives.
It all works thanks to liberal amounts of pixie tears and unicorn poo.
Even though the question is about CA, in my land in Tunisia all those trees that you mentioned are happily bearing lots of fruit in this weather, barely any chill hours if we’re gonna follow the standard Model. No cherries though, not until I get a low chill variety 
I would appreciate any explanations on why with this year colder and more rain in winter and spring, compared to last year almost no chill winter, the trees, grapes and stone fruits, flowered much later so some of the fruits like apricots are still not ripe yet. Usually they are done by now. I thought when the chill hours are met the trees wake up and start flowering. I haven’t seen the farms from San Diego at the farmer markets either, so maybe some members down there can let me know if they have the same results.
California is a weird place climate wise. Where I am in the bay area, I have Royal Rainier cherries fruiting next to my avocados. I also have lots of stone fruit, citrus, and even some experimental tropicals like bananas and guavas. Most are too young for fruit yet, but I know they will all grow here. I could grow apples (my neighbor does), but I’m not a fan.
I really don’t know how many chill hours I get. (the getchill website isn’t working for any station near me). It is rarely below 40F here but we also get a ton of temperatures between 45 and 50F. I have read that no one really knows exactly how 400 hours at 46-48F impacts a tree. The Royal Rainer claims to need 500 hours (but it also claims to need a pollinator but doesn’t seem to), so I guess I get at least that amount. I plan to experiment with grafting on some higher chill varieties . I would like to try a Comice pear, but not sure if 600 hours would be too much most years.
I have a small, local farmer’s market and I haven’t seen much beyond citrus, loquats (pretty much done now) and some other random fruit. In the coastal areas I haven’t seen a whole lot of stone fruit or apple orchards, just the occasional tree in a backyard. You do need to select low chill varieties. My low chill Gala and Pixie Crunch apples aren’t doing too bad, but they tend to have prolonged bloom periods which makes it tough to figure out it an individual fruit is ripe or not. I have a high chill honey crisp and it’s never done anything for me. Last year was the first year that it bloomed and I think that was in June or July. Still hasn’t bloomed yet this year and the top of the tree isn’t awake yet. It’s probably a goner.
But pick appropriate varieties, like Santa Rosa plums and you can get some good results. It does pay to do some research, get to know your local climate and find out what works in your area.
Zone 10a, you must be pretty close to the ocean? I live in the upper Salinas Valley now (where we get more chill), but I’m from the Bay Area. I can’t remember ever having an “almost no chill” winter. Remember that chill hours are above freezing, you don’t need frost to get chill hours.
Answers why one year is wetter/rainier? May as well ask your horoscope. El Niño, La Niña, slight fluctuations in ocean temps in different parts of the world all play a part. The Himalayas impact our weather, so the variables are almost uncountable.
No, whether or not it gets enough chill and when it wakes up are two different things. The plants go dormant when they “think” winter is coming, and they wake up when they “think” it’s spring; it will go dormant and break dormancy independent of chilling. Chilling is (more or less) a prerequisite for fruiting. Analogy is we go to sleep and wake up at night independent of reproduction; reproduction has its own requirements (age, nutrition, etc. 
) that are pretty separate from sleep cycle.
That is what puzzled me. The in ground Fuji is about 25 years old. It had fruits every year except for this year it had no flowers and hence no fruit, just a lot of leaves. I also got one potted Pink Lady last year. It had some fruits when I bought it, and it has flowers and fruitlets now, same as the Golden Dorsett, which is an early low chill variety. All my four asian pears, which are in ground for so many years and gave reliable crops every year, decided to take a break this year and just grow leaves, no flowers. The Santa Rosa plum is pretty old but when it flowered early enough the Splash pluots had very big, red and nice fruits. Otherwise they looked like the picture on Dave Wilson site and didn’t taste very good. This year the Santa Rosa didn’t flower until June but the new Weeping Santa Rosa flowered early and pollinate everything, and the Splash pluots are getting very big now. Since I mostly bought plum and pluot trees when they were on sale in October from Bay Lauren and San Jose I never count the first year crop thinking they might accumulate enough chill hours at the old nursery. However, this is at least the second year for the potted ones and they all get fruits so they must have enough chill hours from my place. I don’t know why Santa Rosa plum only needs 300 hours but ended up flowered much later than others. Thanks for the advice on Honey Crisp. I was looking at them last week at the local nursery. They probably brought them from up north so they all have small fruits. I will not buy them then.
I live about 30 miles east of Los Angeles, toward San Bernardino. It is very hot during summer, and for some years stays hot until November. When I looked at the online nurseries, they classify my area as 10a, and suggest “no” on most of the trees I want to buy because of the heat.
“No, whether or not it gets enough chill and when it wakes up are two different things.”
I agree. However, for most of my trees they have flowers before the leaves come, so I associate that as the trees waking up. I have a lot of plum and pluot varieties, so as long as the flowers open at the same time and compatible, they end up with fruits. I really don’t know from which trees they get the pollens from. I am still not so sure about what factors the trees use to “think” about the climate change so they would go into different states.
Thanks a lot for your reply, I really appreciate it
My plum flowered on time, I should have ripe fruit sometime in early July (hopefully I won’t miss it as I’ll be away on vacation).
I do not know a ton about apples, but if they crop heavily one year, some varieties can turn to bi-annual bearing. That could be an issue, or it could be weather related.
