Vietnam coffee harvest calendar

Flowering

In the Central Highlands the dry season runs from November to April, so farmers, not the weather, decide when the coffee blooms. Once the flower buds are fully formed, usually in late January or February, they give the trees their first heavy watering. The buds open within a few days, and because neighbouring farms water at about the same time, whole hillsides flower together.

The rain-fed arabica areas of Sơn La and Quảng Trị are not irrigated, and the spring rains do that job instead. Sơn La’s coffee flowers from March to mid-May, in two or three waves.

Timing matters. Water given before the buds are ready makes flowering straggle, the national extension guide warns, and that complicates the harvest. When a tree flowers in separate waves, cherries on the same branch ripen weeks apart, and picking only ripe fruit takes several passes.

Cherries developing

The fruit sets and fills out through the wet season, which in the Central Highlands runs from about May to October. For robusta the whole run from flower to ripe cherry takes about nine to eleven months. Little of this is visible to a buyer.

Harvest

Arabica comes in first. In Sơn La and Quảng Trị picking usually starts in October and runs to December or into January. High-altitude arabica around Đà Lạt and Cầu Đất is picked from October to December and can run into February. Lower-altitude arabica elsewhere in the Highlands is earlier still, from August, and is not on the chart.

Central Highlands robusta is the main event. Selective picking starts in places in October, the bulk comes in November and December, and the harvest runs into January. Seasonal pickers travel up from neighbouring provinces for it.

The dates move. Sơn La’s 2023 harvest started about a month later than 2022’s, which is why the chart is a typical year, not a timetable.

Drying and milling

Most Vietnamese coffee is dry-processed. Robusta is picked as whole cherry and dried in the sun, mostly on farmyards and tarpaulins, while the picking is still going on. It takes weeks rather than days: the national extension guide works an example at about twenty days. Collectors and mills then hull, clean and grade it for export.

Arabica is different. Most of it is washed, semi-washed or honey processed and dried as parchment; around Cầu Đất that is about twelve days on raised racks.

Why rain at harvest matters. Cherry that cannot be dried in time heats up, ferments and goes mouldy, and the extension guide warns that holding it more than 24 hours before drying is already a risk. The guide cites the La Niña rains of late 2016 and January 2017 as an example.