This seed starting trick is sometimes known as the baggie method, and it works with paper towels, coffee filters, or even just newsprint.
Count out 10 random seeds from the packet you want to test.
Follow the instructions below to germinate the seeds in a paper towel or coffee filter, and label the baggie with the date you started them.
Look on the seed packet or in any seed catalog for the expected number of days to germination for the seeds you’re testing. Wait that number of days, then count how many seeds have sprouted in that time.
If 8 out of 10 seeds germinated, that gives an 80 percent germination rate, which is pretty good for most vegetables.
If only 4 out of 10 seeds germinated, then you have a 40 percent germination rate and the seed is, for all intents and purposes, useless.