Advantages of grading

Grading of onion sets has multiple advantages:

  • Large degree of uniformity. 
  • In the larger size up to 20% increase in production.
  • Maximum control is possible on desired grading of final product.
  • Maximum control is possible on desired earliness of final product.

Please keep in mind that the large size sets (21-24mm) are more susceptible to bolting.

Yield index


The earliness of the various size classes can vary by up to 6 days. The larger the onion sets, the earlier maturing it is. A second determining factor is the planting density.

Graded sizes and earliness

Graded sizes and size of end product

For the same planting density and growth period, larger onion sets produce a larger end product. However, the smaller size has a longer growing period and by the final grading can be almost as large as the larger size class. 


Harvest second year product