Both total yield and, to a somewhat lesser degree, yield of U. S. No. 1 tubers were increased by increasing the quantity of seed potatoes planted per acre—through closer spacing and/or larger seed pieces. The rate of yield increase declined with each increment of seed potatoes. Planting more than approximately 16 sacks of seed potatoes per acre did not increase the yield sufficiently to justify the greater expense.
Large seed pieces spaced at 71/2-inch intervals produced the highest proportion of small tubers. Potato size was determined more by spacing than by seed piece size.
The yield of “rough” tubers (misshapen, growth-cracked, and second-growth tubers) was slightly and inconsistently affected by size or spacing of seed pieces.