How to grow pistachio trees?
Pistachios are kind of small and slow-growing trees from the cashew family. They are originated in middle-east and Asia. Historically it is believed that pistachios trees were grown in Iran for the first time. Iran is also one of the main producers and exporters of pistachio worldwide. Pistachio growing is kind of technical activity that need enough information to succeed in harvesting most and best crops. It is tried to give some technical information about pistachio growing in the present article.
Pistachio Growing Condition
Pistachio trees are kind of resistant plants. Their ideal growing conditions are as bellow:
- Arid, semi-dried climate, not many plants can grow and tolerate this climate condition.
- Sunny position low humidity, that is why pistachio is a desert plant.
- well-drained soil, simply in this type of soil, water pooling and puddling is not needed because water drains at moderate rate.
- Hot and dry regions which include long and hot summer and cold but not frigid winters, the ranging temperature is between −10 °C (14 °F) in winter and 48 °C (118 °F) in summer. Pistachios are drought-tolerant and they are resistant to hot weather.
Pistachios are born from seeds and choosing appropriate seed is essential in pistachio planting. The seeds have to be raw, not salted or roasted and specific species of pistachios should be used for planting. In Iran mostly small Badami type is used.
In the next step, selected seeds have to be placed in a bowl of water for one to two days at room temperature. Soaking them in water, they have to be covered by wet cotton bags in warm and humid place (20 to 30 degrees). It takes around a week time that seeds begin to sprout. Then the strong sprouts would be transferred to garden. Now it is time to wait that sprouts begin to grow. They usually grow in the beginning of spring, when the weather becomes warmer. As soon as they appear on the ground, they are in danger of being eaten by animals, in order to protect them against animals, they should be covered by bushes. It should be mentioned that irrigation during this period of time is crucial. Every six to ten days they have to be watered
Pistachio hybrid should be done after two years, which it includes some steps and each steps needs appropriate time and procedure.
At first, growers have to prepare trees for hybrid. They have to cut trees branches in winter while the plants are dormant. New branches appear in spring.
Grafting with new branches of other species have to be done in the beginning of summer. The type of pistachio species for grafting depends on the region and the land. Two more years’ time is needed that first crops grow but they are not suitable for commerce. Soil, water, and climate conditions are main factors for harvesting good crops. In the ideal situation the best crops can be harvested in ten to fifteen years’ time. Pistachios like other nuts are alternate-bearing trees, so every alternate year heavy crops can be harvested. Winter is the appropriate time to apply fertilizer in pistachio orchards to encourage trees to grow. Both natural and chemical fertilizers can be used but in Iran mostly natural ones are used.
Pistachios are dioecious plants, it means that there are two separate male and female trees. The trees flowers are wind-pollinated so spring and summer breezes carry pollen from male to female trees. So when growers want to plant seeds, they have to plant both male and female trees. In average, for every ten to fifteen female trees, one male one is needed.
As it was mentioned above, pistachios are resistant and drought-tolerant plants. Although they are resistant to hot and dry weather, irrigation is essential for good crops. The result of some studies indicates that irrigation practice causes increasing fruit yield and also suppressing periodicity, the low fruit yield in alternating years. There are various methods of pistachio trees irrigation including: flume system, electric pumps or drop irrigation. Iran as one the oldest producers of pistachio in the world and also due to locating some deserts in Iran has a long history in water engineering. Extracting and transferring water from a long distance in desert was done by flume system, it was called Qanat in Iran and also it is still used by some growers. It was kind of advanced irrigation system that they may stretch around 90km long.
Although some growers are still using Qanat to irrigate their orchards, extracting water from deep wells by electric pumps is also using. Extracted water from wells by pumps and transfer it to the orchards by pipes is common in some regions too.
Drought and decreasing the level of underground water caused that some growers tend to use drop irrigation in Iran.
Irrigation timing is important in growing more crops. Scientifically it is recommended that 4 to 6 irrigation sessions are needed during the productive period. Young trees should be irrigated immediately after planting and 8 times during the first growing season. Growers usually trust their gained experiences for orchards irrigation. They perfectly know the amount and the time of orchards irrigation. During blooming season and middle summer, maximum amount of water is needed, so every 24 days, pistachios orchards should be irrigated. During winter it should be done every 45 days as trees need less water and also it is raining season in Iran. Irrigation should be avoided two weeks before harvesting time due to more vulnerable fruits to Aflatoxin and insects. The possibility of occurrence of Aflatoxin usually goes up in high moisture.
Pistachios life time
100 years’ life time is estimated for pistachios trees under suitable condition, it can reach to 300 years too. Seven to ten years is approximately required that trees reach production but peak production usually take 15 years.
This article tried to explain pistachio growing conditions in general. If you are interested in pistachio growing, you can grab some information, to get more details, you need to follow more scientific articles. Pistachios ideal growing condition, pollination, irrigation and life span were explained in the article. In the following article we are going to get more information about pistachios, in particular Iranian Pistachios.