How Pistachios Grow
The pistachios we purchase in grocery stores have a hard shell, but we never see the outer hull, which is known as the epicarp. The epicarp adheres to the inner shell until the pistachio ripens, then it is removed.
When to Harvest Pistachios
Pistachios develop in early summer and ripen in late August or September nearly everywhere in the world, with the exception of Australia. In that case, pistachio harvesting generally takes place in February. It’s easy to tell when pistachio harvest season is getting closer because the hulls lose their green hue and take on a reddish-yellow tint. When the nuts are fully ripe, the epicarp turns rosy red and begins to separate from the inner shell as the developing nut expands. At this point, the epicarp is easy to remove from the inner shell by squeezing it between your fingers.
Harvesting Pistachio Trees
Harvesting pistachio trees is easy because Mother Nature does most of the work. Just spread a large tarp under the tree so the ripe nuts aren’t harmed by falling in the dirt. Pistachio orchardists use mechanical “shakers” to loosen the nuts, but you can dislodge them by rapping the branches with a sturdy pole or a rubber mallet. At this point, pistachio harvesting is simply a matter of gathering the dropped nuts. To maintain flavor and quality, remove the epicarp within 24 hours of harvest.