Pistachios

You can grow these tasty nuts in your own backyard, if you have room and patience.

The delicious flavor of pistachios doesn’t come cheap. They are not inexpensive and they require effort to pry from their shells. That being said, pistachios have a protein-rich flavor that begs us to eat just one more, and another, and another.

Immature pistachio cluster (Paolo Galli) CC BY-SA 3.0

What are pistachios?

The meat of a pistachio (Pistacia vera L.) is not technically a nut. Like apricots, olives, cherries, coconuts, and mangoes, pistachios are drupes, or stone fruits. Pistachios are the edible seeds held within a hard shell. When these seeds ripen, the shell pops open with an audible pop. In the world of botany, the thing that makes a drupe a drupe is that the fruit develops from a single ovary.

How do pistachios grow?

Pistachio trees need long, hot, dry summers and gentle winters to produce those hard-shelled nuts. Pistachio trees can tolerate a lot of salinity as long as they get hot, dry summers. Soggy soil will kill your pistachio tree, so good drainage is critical. Pistachios are a slow-growing, alternate bearing, deciduous tree that needs 600 to 1500 chill hours, depending on variety, to produce fruit. Those chill hours can be hard to come by in many warmer regions, but the trees are lovely and some varieties can be very productive. A healthy, mature pistachio tree can produce 110 pounds of seeds every other year. That’s a lot of pistachios!

​Pistachio varieties

The following cultivars have been shown to produce well in the warmer regions:

• Golden Hills - female; large yields; early maturity
• Kerman - female; minimal flavor; large yields; late maturity; susceptible to navel orangeworm
• Lost Hills - female; large kernels; large yields; early maturity
• Peters - male; abundant pollen; late pollen shed with insufficient chill hours; not suitable paired with Kerman
• Randy - male; early pollen shed; best paired with Golden Hills and Lost Hills

Pistachio pollination

Pistachio trees are dioecious. That means there are both male and female trees. You only need one male for up to 10 females for successful pollination, but these trees get rather large, so you probably won’t have room for more than one of each. Mature trees can reach 33 feet in height and should be spaced 20 feet apart.

How to grow pistachios
Plant pistachio rootstock from January through early May. Be sure to provide support by inserting a large, heavy stake next to the root ball. You will want the wind to push the tree toward the support for the best development. Irrigate the root ball immediately and follow with regular waterings until the root system is established. This may take several months, so be patient. Your pistachio tree will also need to be fertilized regularly. During the first dormant season, cut the top of the main shoot off, just above leaf buds. This heading cut will promote a solid structure later on.


Pistachio pests and diseases

A disease called panicle and shoot blight, caused by the Botryosphaeria fungi, kills flowers and young shoots of pistachio trees. In 2011, 50% of the Australia pistachio harvest was lost to anthracnose. Verticillium wilt can also be a problem. Severe drought has also reduced commercial production in many areas. Common pistachio pests include leaf-footed bugs, mealybugs, nematodes, and late season navel orangeworms.

Harvesting pistachios

After waiting for 5 to 7 years, you will finally be able to harvest your very own pistachios. Like almonds, this is done by shaking the tree. Ripe nuts fall and are collected from the ground. If you see any nuts with mold, toss them in the trash. That particular mold is carcinogenic. Also, be sure to dry your pistachios out completely before storing - they have been known to spontaneously combust.

Don’t let all those problems discourage you or scare you off. These beautiful trees can produce an edible crop for decades, if cared for properly.