Peonies perform best when planted in cool climates largely because they require a significant dormancy period before setting blooms. Commercial growers and some home gardeners living in warmer climes fulfill this requirement by chilling the potted plants or naked tubers in a fridge for between 100 and 300 hours, depending on the cultivar, in the late fall and winter.
Provide a refrigerated space to accommodate your potted peony plants or naked tubers for a period of up 300 hours or more at temperatures consistently between 30 and 40 degrees F. Consult the tag or label on your peony plant to determine the minimal cold set period for your cultivar.
Cover the top of potted peony plants with plastic sheeting to help hold needed moisture in the soil. Secure the plastic loosely over the top pf the pot and leave the bottom container holes uncovered to allow for air flow.
Nestle bare peony tubers in slightly damp sphagnum peat moss or damp clean sand and store in a resealable plastic bag or lidded container.
Inspect the stored peonies periodically to check for moisture levels or disease problems. If the soil of the potted peonies feels dry to the touch an inch down, water lightly and replace the covering. If the moss or sand medium feels dry or the tubers look desiccated sprinkle in some fresh water and reseal the bag or container. Remove and discard any moldy or rotting tubers immediately.