Fruit tree selection based on chill hours

Question: I am in the process of ordering a couple of fruit trees online. What are the chill hours for our region? I thought it was 300 hours or less. A couple of apricot trees you have recommended have been 400 and 500 hours (Blenheim and Royal Rosa), and I am wondering if that is too many.

Chill hours are the number of hours at low temperatures during our winters so that the tree "recognizes" that winter has arrived. It can be important in commercial production, but in home orchards, it seems to be less important on some types of fruit trees.

On peaches and apricots in particular, we have not seen a big impact from a lack of chill hours in our area. We have varieties in the 800- to 900-hour range that have done well.I would be most concerned with how the fruit develops in our climate. The recommendations on my list have all proven themselves for a decade at the orchard. I do not release names of those varieties that have a track record of only a couple of years. They remain under testing even if they show extremely good potential.

One variety of peach has been recommended by volunteers at the orchard because of some good qualities in the first year of production. This is way too soon to tell. I prefer at least five years of good production.

Bob Morris is a professor emeritus in horticulture with the University of Nevada and can be reached at Visit his blog at