How to Grow Pistachios
To grow pistachio trees, purchase a young male and young female grafted tree from a nursery. However, before you invest time, money and effort, be sure that you live in the right climate to cultivate them. Pistachios will only grow in the Southwest where the summers are long, hot and arid and the winters cool.
When in the appropriate environment, these trees can grow to 30 feet in height and produce up to 50 pounds of pistachios. However, this slow growing tree does not begin to fruit until it is at least 7 years old and will not reach full capacity for another 10 years and then only if both male and female pistachios are present in your yard.
Choose a planting location. Pistachio trees should be planted where they can receive full sun for most of the day. But that is their only primary requirement. Pistachio trees are notoriously hardy and can survive in even poor soil as their roots run very deep. However, they will fail to thrive if grown on lawns: the frequent watering and moist soil that most grasses require is too wet for pistachio trees.
Transplant your pistachio trees in spring. Dig holes slightly larger than the containers that they are already in, but just as deep. Paired pistachio trees should be planted 30 feet apart.
Carefully remove the trees from their containers, taking care not to disturb the root balls too much. Inspect the roots. If any have coiled around the bottom of the root ball, trim them with pruning shears.
Once the trees are in the ground, pack the hole with some of the dirt that you removed. Then pack the dirt with your feet to remove any air pockets.
Water your pistachio tree. Soak the tree with water after it is first transplanted. From that point on, your pistachio will need deep but infrequent watering. Running a slow hose at its base for 4 hours once a month is often sufficient.
Stop watering your pistachio tree completely in October to help the tree become dormant for winter. Once your pistachio tree has become dormant, resume watering it monthly (reduce the amount of water) to help it become cold resistant.
Fertilize your pistachio tree. Your pistachio tree should not be fertilized for one year after it is planted. The following spring, begin fertilizing it annually in spring with a complete 10-10-10 organic fertilizer.
Wait for your pistachio tree to fruit. The fruit will emerge in summer, after the tree has bloomed. A single fruit will develop in each cluster of blooms. The fruit is covered by a husk, and inside that husk will be a seed or pistachio nut. The shells will turn brownish-red and open when they are ripe and ready to be harvested.