Easiest way: Plant outdoors as soon as they ripen. If seeds are obtained in the fall or winter, you may plant them in the spring. Some peonies will emerge the spring after planting, some will take an additional year to germinate.
The information is a combination of my own experience, information obtained from an article by Don Hollingsworth that was published in a Bulletin of The American Peony Society and information from both Nate Bremer of Solaris Farms and Harvey Buchite of Hidden Springs Flower Farm.
*Soak the seed in water for several days (I usually do anywhere from 5-8 days), change the water once or twice a day to ensure freshness. You will hydrate the seed and possibly help remove germination inhibitors. Discard any seed that becomes mushy or moldy during this process.
*Place the seeds in a plastic bag, (Ziplock freezer quart bags work well for a few seeds, gallon size for more)with slightly moist vermiculite, peat moss or seed starting mix that is soil free) Close bag tightly.
*Place seed bag in warm area. 75-85 degrees Fahrenheit. This temperature range is optimal. At room temperature, incubation will take much longer and will not be uniform. Places I have found success are the top of my water heater or laying in next to the hot water pipe coming from the water heater. I have also had success using a seedling heat mat. Using a thermometer and having an exact measure of temperature is very helpful.
*Check on your seeds every two weeks, check for moisture in the bags and seed condition. You may not notice any change in the seeds during incubation period. Normally this stage takes three months.
*After the incubation period is complete, move the bag to a cool location between 45-60 degrees Farenheit. Optimal temperatures are important. Too cool may lengthen the time it takes for roots to form, too hot may inhibit them from forming at all. Roots will start to appear in a few weeks and may grow 6 or more inches in length. You will be happy when you see these!
*After roots have formed, move the seeds to temperatures nearing 35-40 degrees Fahrenheit. I have used my refrigerator veggie crisper drawer to maintain this temperature. This step overcomes leaf dormancy. If your temperatures are cooler, this will happen at a slower rate (again, thermometers are really helpful). Once the leaf emerges, you can either pot them up in pots deep enough to accommodate the root or plant outside. I tend to pot up first and place under a shade tree to help harden off for two weeks, before planting out, Bill Seidl shared that tip with me. If growing in pots, be sure to keep evenly moist, never wet because it will cause rotting.
* The first season your new peony may produce a single leaf. Providing fertile, well drained soil, keeping them evenly watered (not too wet though, they hate wet feet) and protected from hot sun will keep your seedling happy. In late fall, in cold climates, mulching your seedlings will protect them. Most seedlings will bloom in 3-5 years, some tree peonies can take a year or two longer than that. Your patience will be rewarded.
