Vietnam's cassava and sweet potato seasons: a buyer's calendar

Why the calendar matters to a buyer

Cassava and sweet potato are annual root crops. They are lifted once, dried, and then processed into chips, pellets or powder. Three things follow for a buyer of feed ingredients:

• New-crop availability. The first dried material from a harvest reaches the market a few weeks after lifting begins. Orders placed before that are filled from the previous season’s stock, where a supplier holds stock.
• Drying. In the Southeast and Central Highlands the cassava harvest falls largely in the dry season (roughly November to April), which favours sun-drying of chips. Mechanical drying is used where weather or volume requires it.
• Price and competition for roots. In 2023 Vietnam exported 2.95 million tonnes of cassava products worth USD 1.3 billion, and one market took about 91% of that volume [5]. Starch factories and chip exporters buy from the same harvest, so root prices move with the season and with demand from the largest buyers.

Cassava: where it grows

Vietnam grew about 528,000 ha of cassava in 2022, with an average yield of 20.3 t/ha of fresh roots and total output of 10.7 million tonnes [4]. The Department of Crop Production’s breakdown of the main regions, as reported in 2024 for the 2023 season [5] (figures are for that year; area and provincial names change over time):

The Southeast and Central Highlands have long been the heart of the export-oriented cassava economy: a 2005 CIAT review put the Southeast alone at about 41% of national production at the time [6]. As of 2023 the country had 142 cassava starch plants with a combined designed capacity of 13.4 million tonnes of fresh roots a year [5].

Cassava: when it is planted and harvested

The National Agricultural Extension Centre’s cultivation procedures set out the planting windows by region [1, 2]:

Cassava is harvested 8–12 months after planting, depending on variety, soil and the farmer’s need for cash or land [2, 6]. Applying that range to the planting windows above gives the following derived harvest windows — they are a calculation from the extension calendar, not a reported statistic:

An older FAO/IFAD table summarises Vietnam’s cassava harvest as running from October to March overall, with planting concentrated in March–May and a smaller September–November window [3]. The two pictures fit together once the regions are separated: the October–December lifting in that summary comes mainly from the earlier-planted coastal and northern crops and from short-duration or early-lifted fields, while the Southeast and Central Highlands crop planted in April–May is lifted mostly from December onward.

What this means in practice:

• December–April is the main new-crop season in the Southeast and Central Highlands. Starch factories run at full capacity and chip drying is at its peak in the dry months.
• October–November sees the first new-crop roots nationally, largely from the coast and the north, and from early-lifted fields elsewhere.
• May–September is the growing season in the main export regions. Supply comes from dried stock, from the secondary planting and from other regions.
• Buyers who want material from a specific harvest should ask the supplier which region and planting the lot comes from, rather than relying on the month alone.

Sweet potato: where it grows and when

Sweet potato is grown on a smaller scale than cassava and in shorter cycles. Three regions matter for export-grade material:

Mekong Delta. Vinh Long province, and Binh Tan district in particular, is the established export cluster, dominated by Japanese purple varieties. Provincial sources describe two main crops: an early crop planted in November–December and harvested in February–March, and a later crop planted in April–May and harvested in July–August [8].

Central Highlands. Dak Lak reported around 10,000 ha of sweet potato in 2023, with output approaching 300,000 tonnes and yields of 25–30 t/ha in a good year, concentrated in Lak, Cu M’gar, Krong Nang, Krong Buk, Krong Ana, Krong Bong and Ea H’leo districts [11]. Gia Lai’s Phu Thien district grows a winter–spring crop on 1,500–3,400 ha, depending on the year [10]. Press reports from both provinces describe the winter–spring crop being lifted in late March and early April [9, 10].

North. Sweet potato is grown in three seasons: a winter–spring crop planted in November–December and harvested in April–May; a winter crop planted in September–October and harvested in January–February; and a spring crop planted in February–March and harvested in June–July [7].

These are regional calendars from provincial sources and press reports for particular years [7–11], not a national statistic, and the acreage in each area changes from year to year with prices. Read them as a reference: for dried sweet potato ingredients, February–April is the window in which new-crop material from the south and Central Highlands is most likely, with a second window in July–August from the Mekong Delta. Confirm the crop and region for any specific lot.

A combined calendar

Timings shift by a few weeks with the weather in any given year, and individual farmers lift earlier or later depending on price. In the Central Highlands and Southeast the rainy season normally starts in April or May, which is why extension guidance anchors planting to the onset of the rains [1, 2]. The calendar is a planning reference, not a delivery schedule.

How to use this when sourcing

1. Ask about crop year and region. A quotation for cassava chips or pellets in, say, August is likely to be filled from stock harvested the previous season, if the supplier holds stock. Ask which crop and region the lot comes from and when it was dried.
2. Time enquiries for new-crop material. If you want material from the coming harvest in the main export regions, enquire in the fourth quarter and confirm with the supplier when new-crop lots will be available; availability depends on the supplier’s sourcing and stock, not on the calendar alone.
3. Expect moisture to follow the weather. Drying conditions are best in the dry season. For shipments produced in or near the rainy season, specify the moisture limit and ask how the lot was dried.
4. Watch the starch market. Because starch plants compete for the same roots, a strong starch export season can tighten root supply for chips and pellets.