Critical grading and sorting may result in discarding from 10 to 50 percent of the crowns. Crowns which are very small should be discarded. Crowns which have long spindly roots and many pointed buds, regardless of crown size, should be rejected as well. Also, if too many roots are cut off or damaged, the loss of fleshy storage roots results in the reduction in food reserves necessary for crown growth after field setting. The seedlings are grown in greenhouses for 10-12 weeks depending on vigor and then transplanted, giving them an extended first year's growth.
Transplant seedlings grow best in peat blocks.
Seeds are planted about 1 cm deep, one seed per cell. Plants grown in pre-formed trays should be watered evenly to insure uniform plant development. After seedlings emerge, nutrient requirements can be met by adding a complete liquid fertilizer to the irrigation system. In some nurseries, plants are hardened-off with shade 3 days before planting. The most favorable time for planting is usually mid-May.