This depends on the seeds and what specific variety you are growing. Germination rates vary by species, and seed germination can be impacted by seed age, how they have been stored, and the climate that they are growing in. (i.e. older seeds that may have inadvertently been exposed to temperatures below 32F will be unlikely to germinate).
If you purchased pre-planted SeedPods from us, please contact us at email@example.com and we will help troubleshoot. If you planted your own seeds, please refer to our 'Plant Your Own' Guidelines for tips for sourcing and caring for self-planted plants.