I dried a large mint plant (catnip) in my kitchen, hanging it upside down from the ceiling with a plate underneath for the dropping seeds. The leaves go into a ball jar for tea, the flowers go into a little muslin bag for potpourri, and the seeds into an envelope in my seed storage box.
I was so glad to collect those seeds. It was always my intention to grow from seed to seed, and I never diverted from the “from” part. But I didn’t harvest the seed from many plants, like my tomatoes and even the green beans, because I got typically bogged down and intimidated by issues of cross pollination. Also, most of the seed envelopes I ordered at the beginning of the season are still more than half full, so I felt no urgent need.
But I will save the seed from the many herb plants that are still alive on my porch (we haven’t had a serious freeze yet). I’ll have to find another room and a different setup though, to dry that many. It will be good to figure it out for next year.