Viability Generally speaking, with seeds big and fat is good! The larger and plumper a seed (relative to other seeds of its type), the greater the viability. When separating seeds with the wet method the seeds that float can be discarded as they will not be as strong as the seeds which sink. For seeds of peppers, eggplant, etc. which don’t require fermenting you can assess potential viability by placing in water for 24-36 hours and, as before, saving those that float, discarding those that don’t. (Those that float are not always ‘empty’ seeds but research has shown that they are not as vigorous as the heavier ‘sinkers’.)