Government of New Brunswick

Seed Size Distribution

To obtain uniform potato stands and achieve quality it is essential to cut the seed within a specific size range. The ideal seed piece is blocky because this shape provides the lowest surface area per weight ratio and is easiest for common planter mechanisms to handle. Long pickle shape seed as well as under or over sized seed results in skips and doubles. Potato planter performance, for optimal seed spacing, is dependent on the quality of the cut seed, the precision of adjustments and operation of the planter. A seed size range of 35g to 65g is acceptable depending on the variety being cut and the number of eyes desired per seed piece.

Monitoring Seed Cutting Operation

Seed can be cut manually or mechanically. One of the most important ways to improve seed cutting practices is to monitor weight, shape and number of cut seed surfaces. This will provide information needed to obtain the desired seed piece. Examination of sizer performance combined with accurate adjustments will improve the quality of the cut seed. To obtain smooth, even cuts, the cutting blades or knifes must be sharp and installed properly as outlined in the operator's manual. It is also very important to disinfect the seed cutter between seed lots. Special attention should be given to the sponge roller at the point of contact with the cutting blades.

Sizer performance is influenced by the size and shape of tubers to be cut. A run of small or large tubers can easily overload the sizer beyond its capacity. The recommended size range of mother tubers is 84 to 280 grams.

To improve plant stands, it is important to eliminate seed pieces weighing less than 28g. This operation is usually performed by a set of adjustable rollers. The proportion of undersize seed should be as low as possible. Proper adjustment of sizers and maintenance of appropriate distances between rotary cutter blades on the two cut operation are desirable to reduce the proportion of undersize seed and potential removal of apical buds.

Careful handling of seed is essential to minimize bruising of the tubers and consequent changes in physiological aging of the seed piece. It is also important to properly prepare the tubers for the cutting operation by warming before cutting. Provide proper storage for cut seed before planting. (refer to the previous section)

Closer attention to the above mentioned details can improve