Harvesting dahlia seeds can be lots of fun. Each seed collected has the potential to grow into a brand new dahlia plant that has never been seen before.
If you allow the bees to fertilize the dahlias through open pollination, they will most likely develop pods with some seed. Bees are excellent pollinators.
You can save some dahlia seeds and try your luck growing them. The seeds may not produce a plant as beautiful as the parent plant, however you may be pleasantly surprised.
If you have lots of similar plants together however, there is a likelihood that the bees will travel from one bloom to another, cross pollinating these blooms.
Check on maturity of the seeds by pulling back the bracts, and if you see a large dark black or brown seed, that is an indication of maturity and readiness for harvest.