Is it possible to grow pistachios in the northwest? The Medford area for example?
Jackson County Oregon
Most pistachios are grown in California. Medford does not have the right climate for good production. The ideal locations for growing pistachios are areas that have cold but not frigid winters, hot summers, and little rain. Semi-arid desert locations are ideal. Pistachios prefer temperatures that are above 100℉ during the day. The trees need winter months that are cold enough to send them into dormancy, around 45℉ or below. Pistachios don’t like high elevations because of the cooler temperatures that reach below 15℉. Pistachios don't grow well in areas with high humidity.
Here are a couple of publications you may find useful.
Hope this helps!