Question: Hi. My area receives 800 chilling hours. Does a peach tree requiring say 500 do just as well as one with a chilling hour closer to 800? Also, does one which require more chilling hours bear a better quality fruit, or perhaps larger, in an area that has more chilling hours than required?  Pete - Atascadero, CA

Answer: Hi Pete - thanks for the question with a complicated answer.

* First some easy information which most people already know.  A fruit tree that requires 500 hours chilling needs to have 500 hours or more chilling to reliably fruit and sometimes to even leaf properly.  To plant a fruit tree with high chilling requirements into an area of lower chill will make for an unhappy homeowner and an unhappy tree.  If a tree cannot leaf properly, it will not generate the food with its leaves to survive well.

* Will planting a lower chill peach into an area of higher chill produce better tasting or larger fruit or create any problems?  Most fruit will get its taste from genetics, the nutrients/minerals in the soil, and weather near the growing-harvest season, not from winter chill many months before the harvest.

*One risk of putting a low chill fruit into a higher chill (ie colder) area is frost damage on flower buds.  As a pretty reliable rule of thumb, most peach and nectarines flower earlier if it is low chill and flower later if it is high chill.  This does not hold true for Apricots, Apples and Pears.  So a lower chill peach in a higher chill (often colder climate) could run the risk of a late frost killing the fruit blossoms and depriving you of your summer fruit.  Higher chill areas do not necessarily have a higher risk of late frosts so you have to know your area.  For example, our San Joaquin Valley which is the richest agricultural area in the world, usually gets 800-1400 hours chilling.  Most of that chilling comes in a normal year where rainfall puts moisture in the soil and the climate conditions cause a ground fog to appear that can turn the daytime into a refrigerator running 33-38 degrees for weeks on end.  But we rarely get hard freezes late.  And if we do, the rest of the country will be paying a lot more for their freesh fruit.  Atascadero is not known for late hard freezes either.  In fact your climate is close enough to ours, that you can grow most everything we do.

* It used to be a fact that some of the best peaches came off the trees later in the season - later in July and August. Some of the historical favorites such as Elberta, Rio Oso Gem, J.H. Hale were late July to August ripening. Please note that chill hours are not directly related to ripening time.  There are low chill peaches that ripen late and higher chill that ripen earlier.

In more recent history, there has been a trend to breed fruits to ripen early when the prices from the markets are better.  For a long time these were inferior tasting although they looked good.  We have always argued that the breeders were killing their farmer sales when the early fruit tasted so bland that the customers did not come back all season to get the better fruit.  That is one reason we have taste tested hundreds of varieties and made recommended variety lists for your the various climates based on the best flavored fruits.