An individual fern can produce spores numbering in the millions, and they're easy to collect from the ones in your yard or even in the wild. The trick is to know when they're immature, too mature, or just right for picking.
Nancy Swell, a Richmond, Virginia gardener and contributor to the Brooklyn Botanic Garden's handbook about ferns, warns that once a frond is picked the spores will not ripen further, so care should be taken in your selection. She will also demonstrate a simple way to separate the tiny dried spores from the chaff.
For more information on starting ferns from spores and a complete list of easy-to-grow ferns, see Nancy's article, "Fern Propagation, Simplified," in the January/February 2000 issue of Fine Gardening (#71).