Pistachio trees usually grow on traditional plantations so all the standard may have not met by growers and the orchards are mostly grown experience-based. The growers usually follow different harvesting methods in pistachio orchards in different regions. Pistachio growing and harvesting has a long history in some countries like Iran so experience plays an important role in growing. Some technical information was mentioned in our last published article how to grow pistachios . Some more information is going to be indicated in the present article in the follow of the previous one.
Pistachio harvesting should be done in specific time and it includes some procedures.
Pistachio harvesting time:
Pistachio trees blooming like other nuts, need a bit warm weather, it usually starts in late March after spending three-month dormant from December to February. First trimming pistachio trees usually do in late February to early March and the second one should be done after buds sprout, in mid-June to July. Female trees pollination happens by April wind and rapid seeds expansion begins by August first. Harvesting usually takes four to six weeks’ time which it starts in September. Pistachios grow inside a grape-like cluster. Hull is the outer skin of pistachio and its thickness is about 1.16 inches. Hull adheres tightly to the hard-inner shell until the nut is ripe. Pistachios are ready for harvesting while the hull color turns rosy from green and also they are easy to peel and split inside shell. The harvesting time is different in each area as it depends on climate and orchard location.
The most important period of time for pistachio growers is harvesting season, as the early or late harvesting may cause crop damages in quality or quantity. Harvesting procedure is as bellow:
- Crop picking
Crop picking starts when the pistachios ripen and pistachios tend to naturally fall off the tree as they grow in cluster like grapes. The crops are gathered by hand, net or some other means. In some regions like Iran, Turkey and Syria due to lack of space between trees and rows, laborers harvest pistachio clusters by hands. Most harvesters also use some shacking machineries to shake the branches and help nuts to fall off.
- Separating hull from hard shell
Picking up pistachios manually or by the help of shakers, they have to be carried to factories by trucks for processing.
The first step after being carried to factory is separating hull from hard shell. Removing external shells is done by machines, it may be done in two steps, around %95 of shell removing will be done by first machine, and the rest can be separated by another machine.
- Washing products
The shell-removed products should be washed in the next step. They are usually washed twice by a special machine.
- Drying crops
After washing pistachios, they need to be dried to reduce humidity and decrease moisture level of pistachio to around 25% as humidity causes faster crop deterioration. The can be dried in the sun or by driers.
- Separating cracked and closed nuts
Drying crops, all cracked and bad shaped should be separated and also closed mouth and open mouth will be separated too.
In this step, the crops should be spread on a concrete land in an open air and expose to the sunshine for 24 to 48 hours. They have to be supervised to be protected from birds and replace them every three to four hours to be ensured both sides were exposed to the sunshine. Sorting should be done again in this stage and bad colored and shaped have to be removed again.
The last stage is packing which usually is done in 50kg bags. So the harvesting procedure is done and the crops are ready to be transferred to market.
Some notes should be noticed in the harvesting and processing pistachios. They are as bellow:
- Crop harvesting should be done at the right time. Early or late harvesting, both are not recommended as they cause crop damages, but early harvesting is better than late one as it helps to prevent the occurrence of Aflatoxin.
- In case of high quantity of crops, harvesting speed is important, as a little delay will influence the crop quality of final product.
- All the procedure condition should be hygienic to prevent microbiologic problems.
Control Plant pests
Pistachio gardens are in danger of insect or pests. The insect occurrence is usually due to contamination inside the orchards or around them. Some strategies can be used to control plant pests and prevent any kind of contamination in garden. What usually growers do is as bellow:
- After pruning trees and cutting dry branches, gathering and burning them, not leaving them in garden
- Washing trees during summer and spring with cold water. It causes that trees be fresh and clean during hot days of summer.
- In case of insect appearing, using chemical anti pest to control them
- Choosing appropriate anti pest and dose based on the detected insects, agricultural experts should visit the orchards and introduce the most suitable anti pest.
- Using any kind of anti pest 45 days before harvesting is not allowed.
Growing pistachio trees needs enough information and experience along with patience. Harvesting the most and best products are determined by a combination of different factors.
They do not grow in any regions; the growing condition should be provided. Planting pistachio seeds, pistachio hybrid and irrigations also effects the amount of crop. It should be noticed that the first crops grow usually after seven years but peak production usually take 15 years.
Crop picking, separating hull from hard shell, washing products, drying crops, separating cracked and closed nuts, sorting, and packing are different steps of pistachio harvesting. The right time of harvesting is also one of the most important factors in quality and quantity of crops. Controlling pests and insects should be done by the help of expert`s knowledge and experience to prevent any kinds of contamination in orchards.