Things You'll Need
Large tarp or canvas
Safety helmet and goggles
Pistachios are nuts grown around the world on trees up to 20 feet tall. In the United States, California is the largest producer, although pistachios are also grown elsewhere in the southwest. Pistachio trees yield an average of 1,050 lb. per acre, although that can be as high as 3,300 lb. per acre, or 50 lb. per tree. Harvesting pistachios is as simple as shaking the branches, although nuts also need to be hulled and dried before they are stored.
Watch the pistachios for signs of ripening. One to three weeks before harvesting, the hull of the nut will turn from green to a more reddish color. In addition, when the pistachios are ready to be harvested, the skin of the nut will become opaque instead of translucent and the hull will loosen. All nuts, including pistachios, taste best when they are harvested as soon as they are ready.
Spread out large tarps or pieces of canvas on the ground under each tree that is to be harvested. These will make it easier to collect all the pistachio nuts and prevent them from being contaminated.
Put on a helmet and safety goggles to protect yourself from getting hit by pistachios as they fall from the tree.
Lightly hit the branches of the pistachio tree with a long pole to knock the nuts onto the ground. With trees over 10 years old, the pistachios can also be harvested by shaking the trunk of the pistachio tree to cause the nuts to fall.
Hulling and Drying Pistachios
Hull pistachios as soon as possible because leaving hulls on can cause staining of the shells and growth of mold. This is best done by rubbing pistachios over a screen-top table or a piece of hardware cloth.
Separate blank nuts, or empty shells, from the rest of the pistachios by putting the nuts in a large bucket of water. The blanks will float and can be removed. Being in water will also help the remaining shells to split more easily while they dry.
Dry pistachios to a moisture content of 5 percent or less. This can be done by spreading them no more than two nuts deep on tarps outside for three to four days, or by drying them in an oven at 140 to 160 degrees Fahrenheit for 10 to 14 hours.
Store pistachios in their shells for up to one year in the refrigerator or up to three years in the freezer.
Because pistachio hulls and shells are often cracked when the nuts are harvested, they can be contaminated if they are in contact with the ground. Tarps should be spread under the tree and nuts that fall beyond the tarps should be discarded.