Pelleting is the process of coating seeds with inert materials to make them uniform in size and shape. Whether direct seeded in the field or sown in flats for transplants, pelleted seed allows for greater accuracy and results in a more efficient seeding process.
This video is from Johnny’s Selected Seeds
They also have a pdf information test:go to PDF
But pelleting seeds shortens the shelf life of the seeds. About 1 year in my case.