There is enough variety in floral shape, color, and plant height in the genus to keep most gardeners interested. I believe this plant is ‘Only the Lonely’ and it is one of my favorites for its dramatic height and trumpet-shaped flowers that glow in the moonlight.
After the flowers have been pollinated they will turn brown and shrivel leaving the seed pod remaining on the stem. As you can see from the photo, the ripened seed pods are brown and open at the end when the seeds are ready to be broadcasted.
At this point you can just tap a Nicotiana seed pod and the seeds will easily spill into the palm of your hand, seed envelope or a piece of paper. A single plant can yield a few thousand of the small, brown seeds. To save and store the seeds, spread them out on a piece of paper in a cool dry location for a couple of days to allow them to dry before storing them in seed envelopes for the following year.
Collecting Nicotiana Flower Seeds
Here's a garden video showing you how to collect seeds from ornamental tobacco flowers. I love plants like Nicotiana because they give you so much bang for your seed saving buck. You'll be able to grow hundreds of these annuals in your garden after saving seeds from just one plant. Although, I should point out that if you're saving seeds from a Nicotiana hybrid cultivar there's no telling what your seedlings will look like.