How to Grow and Care for Pistachio Trees

Pistachio trees thrive in arid, hot locations with lots of sunshine, and late fall is the ideal time to sow seedlings from potted nursery specimens. Pistachios contain a number of acidic chemicals that are poisonous to horses but safe for other animals and people to consume.

Common Name	Pistachio tree
Botanical Name	Pistacia vera
Plant Type	Tree, fruit
Sun Exposure	Full
Mature Size	25–30 ft. tall, 15-30 ft. wide
Soil pH	Neutral, alkaline
Soil Type	Well-draining, sandy, loamy
Flower Color	Green, red
Toxicity	Toxic to horses

Pistachio trees are deciduous trees that belong to the Anacardiaceae family [1]. They produce edible seeds that are widely consumed as snacks or used in various dishes and desserts. There are different types of pistachio trees that vary in their size, shape, color and flavor of their nuts. Here are some of the common types of pistachio trees:

• Iranian Round Pistachio (Fandoghi): This is the most popular type of pistachio tree, accounting for about half of the global production. It is native to Iran and grows well in dry and hot climates. The nuts are round and have a light green color. They have a rich and creamy flavor and are easy to harvest because they roll into the palm of the hand .

• Iranian Jumbo Pistachio (Kalleqouchi): This is the largest type of pistachio nut, with a length of about 22 mm. It is also native to Iran and has a sweet and nutty flavor. However, this type of pistachio tree is very sensitive to cold weather and water shortage, and its yield declines after 40 years of age. It is also more expensive than other types of pistachios.

• Iranian Long Pistachio (Arbari, Badami): This type of pistachio tree produces long and slender nuts that have a dark green color. They have a high kernel to shell ratio and a crunchy texture. They are also resistant to diseases and pests. They are mainly grown in Iran, Turkey and Afghanistan.

• Chinese Pistachio Tree (Pistacia chinesis): This type of pistachio tree is native to China and is mainly grown as an ornamental tree for its colorful foliage. It does not produce edible nuts, but its seeds are used in traditional Chinese medicine for treating various ailments.

• Mt Atlas Pistachio Tree (Pistacia atlantica): This type of pistachio tree is native to North Africa and Southwest Asia. It is also grown as an ornamental tree for its drought tolerance and attractive bark. It produces small and bitter nuts that are not edible, but are used as a source of oil.

• Pistachio Tree (Pistacia vera): This is the most common type of pistachio tree that produces edible nuts. It is native to Central Asia and the Middle East, but is now cultivated in many countries around the world. The nuts have a greenish-yellow color and a distinctive flavor. They are rich in protein, fiber, minerals and antioxidants.

• Pistachio Tree (Pistacia palaestina): This type of pistachio tree is native to Palestine, Israel, Syria and Lebanon. It produces small and hard nuts that have a reddish-brown color. They are mainly used for making oil or as animal feed.

• Terebinth Pistachio Tree (Pistacia terebinthus): This type of pistachio tree is native to the Mediterranean region and Asia Minor. It produces small and bitter nuts that are not edible, but are used for making varnish or as a substitute for turpentine.

• Pistachio of Sicily: This type of pistachio tree is grown in Sicily, Italy. It produces green nuts that have a delicate and aromatic flavor. They are highly valued for their culinary uses, especially in making desserts such as ice cream, cake, pudding and candy.

Since pistachios require a particular type of climate, not everyone can grow them. The most important factors to take into account are the local climate's temperature, humidity, and rainfall. Pistachio trees don't like high humidity or damp soil, and they need very high daytime temperatures. It thrives in loamy, sandy soil that drains well. The best waterings are infrequent deep ones. Give each tree at least 20 feet of space.

Temperature and Humidity

At least during the summer, these trees like the heat. The pistachio tree prefers temperatures that are often around 100 degrees Fahrenheit. Although it enjoys being so hot, it does need a period of winter cold (between 32 and 45 degrees Fahrenheit) for at least 900 total hours in order to start producing new leaves and buds. Pistachio trees, though, can't stand freezing ground. Because of this highly specific temperature requirement—extremely hot summers and cool winters—pistachio can only be grown in a relatively narrow area in the United States.

The pistachio tree does not like excessive moisture, in contrast to tropical plants, which enjoy hot temperatures and humidity. In humid areas, it struggles.

Soil

Although the pistachio tree can grow in practically any type of soil, light, sandy, loamy soils with good drainage are the best. These trees cannot grow in wet, heavy soil. The soil must penetrate far into the earth for these plants to survive because of their lengthy taproots.

Water

The pistachio tree prefers dry environments and is extremely drought-tolerant. Do not, however, use this reputation as justification to neglect watering your pistachio tree. To produce a large crop of nuts, they still need a lot of water.

Deep, infrequent waterings that enable the soil to become completely saturated can benefit your tree. Extra water is welcome in the hot heat. The pistachio does not grow well in damp soil or standing water, so let the water to drain before watering it again. Many individuals utilize irrigation systems for huge orchards.

Fertilizer

It's crucial to conduct a soil test to see what nutrients your soil may be lacking before adding any fertilizer. You can adjust the fertilization to match the nutrient requirements of your tree if it is deficient in nitrogen, phosphorus, or potassium.

To ensure a decent crop, it is better to apply the fertilizer in late winter or early spring.

Light

The pistachio tree prefers hot, arid areas and requires full light for at least eight hours per day.

• Climate: Pistachio trees thrive in areas with hot, dry summers and cool, mild winters. They are well-suited for USDA plant hardiness zones 7 to 10. These trees require a period of winter chill (between 850 and 1,000 hours at temperatures between 34°F and 45°F) for proper bud development and fruiting.

• Soil: Well-draining soil is crucial for pistachio trees, as they are sensitive to root rot caused by waterlogged soil. They can tolerate a variety of soil types, from sandy loam to clay, as long as drainage is adequate. A soil pH between 6.0 and 8.0 is ideal.

• Sunlight: Choose a site with full sun exposure, as pistachio trees need at least 6 to 8 hours of direct sunlight daily for optimal growth and fruit production.

• Space: Ensure there is enough room for your trees to grow. Pistachio trees can reach heights of 20 to 30 feet and require a spacing of 20 feet apart to accommodate their extensive root system and canopy.

The ideal time to plant pistachio trees is in late winter or early spring, when the soil is workable and the risk of frost has passed. This allows the trees to establish their root systems before the hot summer weather arrives.

Purchase trees

Obtain healthy, grafted pistachio trees from a reliable nursery. Note that pistachio trees are dioecious [2], meaning you’ll need both male and female trees for successful pollination and nut production. The recommended ratio is one male tree for every 8 to 10 female trees.

Planting

Dig a hole about twice as wide and as deep as the root ball. Place the tree in the hole, ensuring that the graft union (visible as a bump on the trunk) is at least 2 inches above the soil line. Backfill the hole with the removed soil, gently firming the soil around the roots to eliminate air pockets [3].

Watering

Water the tree thoroughly after planting, and continue to water deeply every 7 to 10 days during the first growing season. Once established, pistachio trees are drought-tolerant and typically only require supplemental irrigation during prolonged dry periods.

For the first three to five years, as potted nursery specimens, these trees can be kept in pots. They should then be put in the garden so the tree can grow. This is important because the lengthy taproot of this species would be inhibited by continued container development.

It is not feasible to grow pistachio trees in pots or as indoor plants for a long time.

Common pests affecting pistachio trees include aphids, mites, and navel orangeworms. Monitor trees for pests and treat as necessary with appropriate controls. To prevent fungal diseases, maintain good air circulation in the canopy and avoid wetting the foliage when watering.

Pistachio nuts are typically ready for harvest in late summer to early fall when the outer hulls begin to split. Harvest the nuts by hand or by shaking the branches, and remove the hulls promptly to prevent staining.

How long does it take for a pistachio tree to bear nuts?

Pistachio trees can take up to 10 years [4] to start producing nuts, and they reach their peak production after 20 years. The trees are dioecious, meaning they have male and female flowers on separate plants. You need at least one male and one female tree to ensure pollination and fruit set.

How much water and fertilizer do pistachio trees need?

Pistachio trees are drought-tolerant, but they need regular irrigation during the growing season, especially when the nuts are developing. They prefer deep, infrequent watering to shallow, frequent watering. They also need well-drained soil and full sun exposure. Pistachio trees do not need much fertilizer, but they benefit from a balanced organic fertilizer applied in early spring.

How do I harvest and store pistachio nuts?

Pistachio nuts are ready to harvest when the shells split open, revealing the green kernels inside. You can harvest them by hand or by shaking the branches. The nuts should be dried in a cool, airy place for a few days before storing them in airtight containers. You can store them in the shell or shelled, but shelled nuts may lose their flavor faster.

SOURCES

The New York Garden works under restricted procurement guidelines and relies on peer-reviewed studies and studies conducted by academic organizations. Tertiary references should be avoided. For more information on how we ensure our material is correct and up to date, please visit our editorial policy.

1. Anacardium Plants: Chemical, Nutritional Composition and Biotechnological Applications - National Institutes of Health

2. Botanical Terminology: Flowers, Houses and Sexual Reproduction - Horticulture and Home Pest News

3. Tree Care: The Planting Hole - Urban Forest Initiative

4. Pistachio Nuts (Pistacia vera L.): Production, Nutrients, Bioactives and Novel Health Effects - National Institutes of Health