Growing
The pistachio harvest: when, how, and the 24 hours that follow
A year’s work comes down to two weeks, and the quality of the harvest to twenty-four hours. Here is how to tell a pistachio is ripe, how to bring it down from the tree, and why you then have to move fast.
The pistachio you buy, beige and half open, looks nothing like the one you pick. On the tree it is wrapped in a fleshy skin that turns pink when ripe, and it hangs in clusters like grapes. The whole job of the harvest is to get it out of that skin and dry it before it spoils.
How do pistachios grow?
In clusters, on the female trees, after flowering in April. The fruit builds itself from the outside in:
- by early June, it has reached its final size, but it is hollow;
- by early July, the shell has hardened;
- from July to August, the kernel grows inside until it fills the shell;
- in August, the kernel pushes so hard that it splits the shell. That is what gives the pistachio its natural opening.
| Part | What it looks like | What happens to it |
|---|---|---|
| Hull | Fleshy skin, green then pink | Removed straight after harvest |
| Shell | Hard, beige, split when ripe | Kept for pistachios sold in the shell |
| Skin | Thin, purple | Edible; removed for blanched pistachios |
| Kernel | Green to yellow | The part you eat |
When are pistachios harvested?
At the end of summer. The date depends on the variety and the region.
| Region | Harvest period |
|---|---|
| Provence | Late August to late September |
| Spain, early varieties | Late August to early September |
| Spain, Kerman | Second half of September |
| Sicily, Bronte | Late August to late September, odd-numbered years only |
| California | Early September to late October |
There is an even earlier harvest: green kernels, picked about a month before full ripeness, when the kernel fills 80% of the shell. They go to pastry chefs and ice-cream makers, who want them for their colour.
How do you know when a pistachio is ripe?
You look at the hull, not the shell. Three signs go together:
- the hull turns from glossy green to a dull pink;
- it slips off on its own when you squeeze the fruit between two fingers;
- underneath, the shell has split.
As long as the hull sticks to the shell, the pistachio is not ready. Waiting too long is no better: a hull that splits on the tree lets in insects and mould.
How are pistachios harvested?
By shaking the tree. The ripe fruit comes loose in a few seconds. On small plots the work is done by hand. On large ones, a mechanical shaker grips the trunk, which is why the trees are trained with a clear trunk for the first 80 to 90 cm.
One rule applies whatever the method: the pistachios must not touch the ground. Sheets or nets are spread under the trees, and the big Californian orchards use catching frames mounted on the machine. The soil brings moisture and mould spores, and a pistachio still in its damp hull is ideal ground for them.
Why must the hull come off within 24 hours?
Because the hull contains tannins. As long as it stays against the shell, they seep into it and stain it brown. Fungi also settle between the hull and the shell. Californian guidelines set the limit at 24 hours; a 2026 press release from Provence speaks of 48 hours. We stick to the shorter one.
This race against the clock has a consequence everyone has come across without knowing it: pistachios were dyed red for years to hide shells stained by late hulling. We tell that story in the article on the colour of pistachios.
How are pistachios dried?
Straight after hulling. At harvest, a pistachio holds about 30% water. It only keeps below 7%.
| Method | How it works |
|---|---|
| Industrial dryer (California) | Down to 9 to 10% moisture in under 24 hours, then 5 to 7% in a silo over two or three days |
| Dryer at a workshop in the Vaucluse | 42 °C for 24 hours |
| Air-dried, at our orchard | Three days |
Drying too hot damages the kernel; drying too slowly gives mould time to set in. A dry, windy September, which Provence often has, makes things much easier.
What gets sorted out after the harvest?
Three defects.
- Empty shells. Some pistachios have no kernel, or a stunted one. They are picked out by flotation: those that float hold less than half a kernel.
- Closed shells. These are usually unripe. They are separated from the split shells, by machine in the industry and by hand at our orchard. In the trade, they are then cracked and sold as kernels.
- Stained shells. They are safe to eat, but kept out of in-shell sales.
How much of each defect you get depends on the variety. In California, Kerman gives about 70% split shells and 10% blanks; the Golden Hills variety, 87% and 4%. In Castile, in unirrigated orchards, Kerman gives more than 60% open shells.
Once dried and sorted, pistachios are kept cool and dry, between 4 and 7 °C in warehouses. At home the rules are simpler: they are in the article on storing pistachios.
Frequently asked questions
When is pistachio season?
In the northern hemisphere, pistachios are harvested from late August to late October depending on the country, and mostly in September in France. Growers have the new season’s pistachios from the autumn onwards.
Can you eat fresh pistachios?
Yes. In producing countries, people eat them straight out of the hull, soft and milky, during the few weeks of the harvest. They keep badly, which is why you almost never find them in shops in France.
Are pistachios harvested by hand?
On small plots and steep ground, yes: that is the case in Bronte, in Sicily. Elsewhere, a mechanical shaker grips the trunk and brings the fruit down onto nets or catching frames.
Why are some pistachio shells stained?
Most often because the hull stayed against the shell too long after harvest, or because rain fell on the ripe fruit. It is above all a cosmetic defect, which is why these pistachios are kept out of in-shell sales.
How long does the pistachio harvest last?
It depends on the size of the orchard and the number of varieties, which do not all ripen at the same time. Our 2026 harvest lasted thirteen days, from 9 to 21 September.
Sources
- Good Agricultural Practices for Pistachio Growers, University of California and California Pistachio Research Board, 2009.
- Flowering, pollinizers and signs of ripeness in pistachio varieties, El Chaparrillo, Vida Rural magazine, 2005, in Spanish.
- Pistachios: production fact sheet, UC Davis, Western Institute for Food Safety and Security.
- Pistachio Cultivars in California, C. Kallsen, UC Cooperative Extension.
- El pistacho (1): requirements, soil, water and year-by-year yields, J. F. Couceiro, IRIAF El Chaparrillo, in Spanish.
- Le pistachier, Pistache en Provence association, in French.
- Press release on the 2026 harvest, La Maison de la Pistache, August 2026, in French.
- 1re grande récolte de la pistache provençale, L’Écho du Mardi, 25 August 2026, in French.
- En Provence, le pari de la pistache, Vert, 22 September 2026, in French.
- La pistache récoltée en amandon vert, Pleinchamp, 13 October 2026, in French.
- Il pistacchio di Bronte, Il Post, 27 December 2024, in Italian.
- Pistachio: postharvest fact sheet, UC Davis Postharvest Research and Extension Center, 2025.
