Corm Size Classification

Corm sizes are approximately the following diameters:

In USA
Group Corm diameter
Extra 2” / 5.1 cm or larger
1 1” - 2” / 3.8 - 5.1 cm
2 1.25” - 1.5” / 3.2 - 3.7 cm
3 1” - 1.25” / 2.5 - 3.2 cm
4 0.75” - 1” / 1.9 - 2.5 cm
5 0.5” - 0.75” / 1.3 - 1.9 cm
6 under 0.5” / 1.3 cm
In Russia
Group Corm diameter
1 1.18” / 3.2 cm or larger
2 0.79” - 1.18” / 2.5 - 3.2 cm
3 0.4” - 0.79” / 1.5 - 2.5 cm
4 0.3” - 0.4” / 1 - 1.5 cm