Selecting a Winning Site and Crops to Match - Growing Organic Orchard Fruits - page 24

Precipitation and Humidity
Arid locations with ample irrigation water are often ideal for orchards. The
lack of rainfall during spring and summer greatly reduces apple scab, brown
blight of stone fruits, fire blight, and other diseases compared to what you
find in more humid areas. The higher precipitation levels and humidity east
of the Rocky Mountains do not mean that you cannot grow orchard fruits or-
ganically, but it will be more challenging than for western growers. If you live
in a rainy or otherwise humid climate, it is particularly important to select a
site with excellent air drainage, improve the air movement on your site, and
select disease-resistant crops and varieties. We'll discuss some approaches
to modifying your orchard environment in later chapters.
Late spring and early summer rains can cause serious problems for
cherry growers. The fruits are susceptible to cracking when rains come just
as the fruits are ripening and into the harvest season. Some varieties are
less prone to cracking than others. For rainy areas, it is important to select
cracking-resistant cherry varieties.
HOW TO SELECT CROPS THAT ARE HARDY FOR
YOUR SITE
1. Identify your hardiness zone using the hardiness zone map or
table 2.1 on page 21 ➔ . For example, Sandpoint, Idaho, is rated
as Zone 6a (−5 to −10°F; −21 to −23°C).
2. Look up the extreme minimum winter data for your area using
the NOAA Regional Climate Center website if in the United States,
or the website of the National Climate Data and Information
Archive if in Canada (see Resources ➔ for both websites). For
Sandpoint, temperatures of −20°F (−29°C) are common, and the
recorded low is −36°F (−38°C).