Cold days are vital to fruit trees

While I have been doing my garden update posts, get comments from people saying they cannot grow some of the plants I have. And the fruit itself is very expensive or impossible to find where they live. These comments mostly come from people that live in regions that do not have much of a winter in southern latitudes.

Just like I cannot grow Mangoes, Avocados, Oranges, Limes and other trees due to our winters. Many cannot grow Blueberries, Apples, Peaches or Cherries due to mild winters.

There is a term "chill hours" that comes into play when talking about fruit trees and how many hours below 45F (7C) they need.

Source: California Lifestyle Farm

Such trees that need the most chill hours are Apple trees, Raspberries, Pistachios and Peaches.

Source: ResearchGate

These cold days will trigger the tree into a state where it will want to reproduce, making fruit with seeds in it to survive. If temps are too high the plant does not feel threatened and will not produce fruit. It seems to be a survival mechanism.

Source: Wilson Bros Gardens

Luckily where I live I get 1000 or more chill hours on average, which allows me to grow just about any fruit I want. As long as the plants can survive the winter.

Some cultivars of Cherry trees such as the Minnie Royal and Royal Lee can fruit with much more mild winters, only needing around 300 hours compared to the 1100-1300 needed for most cultivars. There are other low chill hour cultivars of other kinds of fruit trees as well, ranging from Apples, Apricots, Nectarines and Plums.

So if you are considering buying a fruit tree, bush or vine. Make sure you have winters suitable for them, otherwise you may never get any fruit from them.