Poland: Starch Content Ranges From 13% to 18% as Harvest Shows Uneven Tuber Quality
A Syngenta agronomist tells farmer.pl that some Polish lots reach 17–18% starch while others from the same fields have 13–14%, and some fail the 13% minimum.
The potato harvest in Poland is entering its final phase, and the quality of the tubers is very uneven this year. This is the view of Dr Katarzyna Rębarz, an agronomist at the crop protection company Syngenta, in an interview published by the Polish farm portal farmer.pl on 29 September.
According to Dr Rębarz, yields differ a lot and depend mainly on whether a field was irrigated. Irrigated fields gave good yields. Fields without irrigation gave lower yields and a smaller share of marketable tubers. In some regions, temperatures reached about 40°C in June. This ended the growth of sensitive varieties early, so they could not reach their full yield.
The starch content of the tubers also varies widely, she said. Some lots have 17–18% starch, while other lots from the same fields have only 13–14%. Some deliveries did not reach the minimum level of 13% starch.
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Dr Rębarz listed several quality problems that growers see during lifting this year:
- many cracked tubers;
- common scab;
- Rhizoctonia on the skin;
- secondary growth and misshapen tubers, caused by uneven water supply;
- poor skin set after regrowth late in the season.
Wireworms and Colorado potato beetle also damaged tubers and reduced the share of top-grade potatoes. Late blight was under control in most regions, except in northern Poland. High temperatures between rain periods limited the development of the disease, she said.
The starch figures match earlier reports from the start of the starch campaign. In late August, Ryszard Szaroleta, head of a potato growers’ association, told the magazine topagrar Polska that well-managed, irrigated fields gave 35–40 t/ha with starch content near 17.5%. The same report said starch potato prices for 2026 were about 1.50 zł per kg of pure starch, down from 2.20–2.50 zł per kg in 2025.
Why it matters
Starch content decides how much a grower earns from starch potatoes, because factories pay per kilogram of starch. Lots under 13% may be refused or paid much less. With starch prices already far below last year, a low starch content makes the season even harder for these growers.
For ware and processing potatoes, the listed defects matter for storage. Cracked tubers, scab and secondary growth reduce the share of saleable potatoes and can raise losses in store. Growers should sort crops carefully and keep damaged lots for early sale. Poland’s official statistics office GUS estimates the 2026 potato crop at about 5.9 million tonnes, 15.4% less than last year.
Photo: Potato tuber with common scab (not Poland) (illustrative). Clemson University – USDA Cooperative Extension Slide Series / Wikimedia Commons, CC BY 3.0 us
