I believe peonies require a period of warmth followed by cold. I planted peonie seeds one year not long after I collected them & had some seedlings the following year. Would still have them if I hadn't accidentally sprayed them trying to kill poison ivy.

You can plant them right away in the ground. It is probably the easiest method of growing them. I have done this the past 2 years and have many seedlings from this method. Good luck.

I have seen a suggestion to plant the seed near the mother plant when open pollenated. That way you will know who the parent is. Really bad luck to drop the planted tray/pot and spill everything or have the squirrels & racoons play with your labels. Stuff happens.

"I am going to collect some peonie seeds in just a couple of weeks."
The seeds need to be mature before collecting; here in z5, the seeds mature and the pods split in September.

Various peonies pods split at different times. I have had some ripen as early as late June and as late as August. The majority split in July.

I returned from Peonyman's garden and he has several pods splitting. Most are tenifolia's but I saw at least one tree and one regular plant with splits in the pods.

My "Bowl of Beauty" just bloomed recently for its first time in the 3-4 years i've had it (grew it from a bare root bought online) and i noticed it has seed pods. I"m in a warm region of northern idaho- i'm told our zones are 6a and 6b and 7. i call it a banana belt as we have a couple months longer growing season then nearby western WA state where i used to live. my question now that i wandered off course lol is any clue when these pods will split? and do i replant the seeds this year or next? if so i'm so excited at being able to grow more of this beauty (aptly named!) its one of my favorite peonies!!! how big do the B.o.B's get btw?