Every year in mid August the Dutch farmers association VTA estimates the potato yield based on a standard sampling protocol among its members. These yield measurements are always done at the same time and are now common practice since 2001. The sampling includes a representative group of farmers and covers a wide range of potato varieties intended for consumption (seed potatoes and potatoes for starch production are excluded).

Based on the sampling, the average yield at this time in the growth season is estimated at 41917 kg/ha. This is 16% lower than the comparable measurement of last year when 49965 kg/ha was found. This year's yield is also 7.1% lower than the 5 year average.

The number of tubers in the test samples (taken from 2x3 m plots) was 188, which is rather low compared to other years and the percentage of tubers larger than 50 mm was 57% The 5 year average for this value is 65%.

The tuber size was clearly affected by variety, with larger tubers found for the potato varieties Agria, Innovator and Victoria. Since the number of tubers for these varieties is somewhat lower, the larger tuber size does not result in major differences in overall yield between varieties.

Significant differences have been found between lots. Whether this will still be true at harvest time will depend on the development in the coming months. Since on some lots the potato plants are still completely green, while on other locations the plants have started to die down, there seems to be considerable difference in growth potential between lots.

A number of growers also indicate that some secondary growth has been observed.

Mid September the same growers will be sampled again.