HesapHanem

Potato Seed Calculator

Enter your bed dimensions and spacing to find how many seed potatoes to plant.

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 must be a whole number of 1 or more; a fractional value such as 2.7 or 0.5 gives no result. 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.

Worked example

You plant 4 rows, each 10 m long, with a piece every 30 cm, and an average piece weighs 50 g. One row is 1000 cm, and 1000 / 30 = 33.3, so 33 gaps fit; adding the first piece makes 34 per row. Four rows need 34 × 4 = 136 pieces. At 50 g each that is 136 × 50 / 1000 = 6.80 kg of seed potatoes, over a total row length of 40.0 m.

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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 must be a whole number of 1 or more, so 2.7 or 0.5 gives no result; enter 2 or 3 instead.
  • Leaving the weight blank and reading 0.00 kg as the amount to buy. Without a piece weight the kilogram figure is not calculated.

About this calculator

The potato seed calculator works out how many seed potatoes a planting bed needs from row length, number of rows, and in-row spacing: divide each row's length by the spacing (commonly 25–30 cm / 10–12 in between seed pieces) to get pieces per row, then multiply by the number of rows. Seed potatoes are usually planted whole if small (golf-ball size) or cut into pieces of roughly 40–60 g with at least one or two healthy eyes each.

Getting the count right matters because overcrowding potatoes reduces tuber size and airflow (raising the risk of blight), while too much spacing wastes bed space that could produce more yield. Home gardeners and small-scale market growers use this calculator when planning a bed or ordering seed stock, so they buy neither too few plants to fill the row nor too many pounds of seed potatoes that end up unused.

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Comments (1)

  • Editorial team

    The count here depends only on row length, number of rows and in-row spacing, so it cannot tell you whether the rows fit your bed. Before ordering, compare the distance between rows you plan to use with the bed width you actually have. The kilograms shown are exactly what goes into the ground, with no spare for pieces that fail to come up, so decide separately how much extra to buy. Do you plant whole tubers or cut pieces?

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