It's a great idea to keep track of all the details with each planting. Where the seeds came from, planting method, and nutrients added.
Just because you have a poor germination rate in one or two beds does not necessarily mean that the seeds were bad. If you have four beds with seeds from one supplier and you have two of those beds that have poor germination, then you need to do a process of elimination to figure out what caused poor germination. Like poor soil, disease, planting method. Bed too wet, seeds dried out, animals and rodents eat the seeds also slugs and snails under the leaves will destroy seedlings, etc.
There are many reasons why seeds fail to germinate well. So keep good records of everything.
classicfur