Certified GKH Gardening Expert
Since they require a cold period in order to germinate, fall is really the most ideal time to plant the seeds. However, you can also attempt this cold treatment (called stratification) now. Here is the stratification process: soak seeds in lukewarm water for 48 hours to soften seed coat. Mix seeds with damp sphagnum moss or peat and place in a plastic zip-loc bag for 4-6 weeks at room temperature. Then place in the refrigerator for 60 to 90 days to mimic a natural winter season. After the 90 days, sow in trays or pots.
Once they are cold treated, you can plant them indoors in well-draining potting soil, keeping the soil warm and somewhat moist. When you have adequately sized seedlings, they can be transplanted outdoors. Here is more information on the plant: https://www.gardeningknowhow.com/ornamental/flowers/astrantia/astrantia-masterwort-plant.htm