Do you have seeds that you save to plant at a later date? Seeds that are planted may or may not grow if you do not know how to test if seeds are still good. This is not hard to do and can be done by using one or more methods.
The float method is one option to use for how to test if seeds are still good. This involves putting seeds in a container of water. Seeds that float will likely not grow because they are too dry. Seed which have sunk to the bottom are OK to plant.
Another way for how to test if seeds are still good is the germination method. This is done using a paper towel that is damp. Wrap a few seeds in the damp paper towel and set them in a warm area up to a week. Seeds that germinate are viable and ready to plant.