How to Calculate Spacing in Agriculture

Project your total desired crop harvest for the coming year. Calculate the number of crops per meter that will need to be planted to attain the total figure. Measure each row by meter if necessary.

Calculate the germination rate for a sample of your seed to be planted. The rolled towel method is considered a reliable test of the strength and virility of seed. Low tech and inexpensive, this technique calls for planting seed samples in a thin layer of soil spread upon towels, which are loosely rolled up and placed in climate controlled storage. The ratio of sprouted to unsprouted seeds is the germination rate. Contact your regional extension office for the procedure. Alternately, ask your seed dealer for her estimated germination percentage.

Consult your records from prior years for a ratio between emerged crops and planted seeds. Convert the ratio into a decimal figure. This percentage is the expected emergence rate.

Multiply the germination rate by the expected emergence rate. Divide the number of desired plants per meter by this product. This calculation yields the number of seeds you will plant per meter, e.g., 25 seeds.

Divide the number of seeds into 100 cm, which equal 1 m, to determine spacing. For example, 25 seeds will be placed 4 cm apart.

Spread your rows at least twice as far as the spacing of seeds within rows for determinate crops, e.g., those which produce their full yield at once, with little diffusion of roots. This would apply to corn, for example. Space the rows for indeterminate seeds, such as soybeans or legumes, three-to-four times the intra-row spacing.