Potato Seed Calculator

How it is calculated

The tool counts seed pieces along a row, including the one at the start: pieces per row = floor(row length × 100 / spacing) + 1, with row length in metres and spacing in centimetres. Then total pieces = pieces per row × rows, and weight (kg) = total pieces × piece weight (g) / 1000. Total row length is simply row length × rows. The number of rows is cut to a whole number (2.7 rows counts as 2). Row length, spacing and rows must be above zero. If you leave the piece weight empty, the count is still shown but the weight reads 0.00 kg. The result assumes every row is a straight line with the same spacing; it does not add a reserve for pieces that fail to sprout.

Common mistakes

• Dividing the row length by the spacing and stopping there. A row of 10 m at 30 cm has 33 gaps but 34 plants, because both ends get a piece; the tool adds that extra one per row.
• Mixing units: entering the row length in centimetres or the spacing in metres. Row length must be in metres and spacing in centimetres, otherwise the count is off by a factor of 100.
• Using the weight of a whole tuber when the seed is cut. The weight field is the weight of each planted piece, so a tuber cut in three should be entered as a third of its weight.
• Entering a fractional number of rows. Rows are cut to a whole number, so 2.7 becomes 2, and a value below 1 gives a count of 0.
• Leaving the weight blank and reading 0.00 kg as the amount to buy. Without a piece weight the kilogram figure is not calculated.