Germinating Peony Seeds
Peonies do not come true from seed. You must have named cultivars propagated vegetatively to retain their cultivar name. Some seedlings may resemble their parents, but they are not identical.
Seeds collected from species plants have an inherent variability within the population and not all are exactly alike, even in nature. Be aware that species plants grown in the garden are subject to cross pollination with other peonies that may be in bloom at the same time, but otherwise, plants grown from species seeds remain species plants.
Peony seeds can be started indoors, but, it's rather involved and it has to be started in the fall to get the timing right for planting sprouted seeldings in the spring.
By late winter it is much better to delay starting peony seeds until mid-June, perhaps as late as mid-July. The reason for this is that peony seeds have a stepped approach to germination which has evolved to maximize sprouted seeds emerging in the srping whwen they have the best chance for survival. Seeds need a lengthy warm moist period after which the root starts to grow with the onset of fall weather. The cold of winter is needed to break down barriers which otherwise prevent initiation of shoot growth. This sequence of environmental factors must occur in that order, or the seeds will not grow.
In mid-June to mid-July soak the seeds in water for up to four days. Seeds which sink are considered sound and should germinate for you. Seeds which never sink are usually hollow, and not viable.
Plant out in garden, or in a cold frame, 1" deep, 4" to 6" apart.
Water to dampen the soil and avoid letting it dry out, but, don't keep it constantly wet either.
It is best to cover the seeded area to conserve moisture, to mark the spot, and to protect against animals digging them up. They won't show above ground growth until the spring anyway, so covering won't bother them. Use a board or flat rock or something similar.
Remember to remove the covering as early as you can in the spring.