The growers are very busy at the moment. After harvesting time now they are washing and sorting the flowerbulbs.The size differences arise from the periphery of the bulb in centimeters. The growers sell a circumference of 10 centimeters and larger and put back in the ground bulbs with a circumference of less than 10 centimeters. Tulips are sorted in sizes 10/11 - 11/12 - 12/+ and 14/+. Tulip Store only sells the largest available size per variety and that means for almost every variety size 12/+, meaning the bulb has a circumference of at least 12 centimeters. Just a single tulip grows easily to size 14/+ and so we sell those kinds in size 14/+.