The #3 round has slightly larger volume than the #3 square. The round pot allows for better ventilation and air circulation between pots, advantageous to longer term durability of pot walls. Similar to the #3 square, this size is preferred for seed starting of herbs, vegetables or other annuals that will be used for step up transplants to larger planting containers or direct transplants to ground post frost, with quick turnaround from initial seeding. Once planted, the #3 round stays intact for up to 3 months in a greenhouse setting. If not planted and kept in a cool dry location, shelf life is indefinite.