Fall sowing may have been a better choice. With it now being almost mid March, you may have to do the stratifying (moist chill for the seeds) in your refrigerator. To save space, put the seeds in a tiny zip lock with a small amount of moist sterile sand or moist vermiculite...just a tsp will be fine for several seeds - they don't have to be buried. Write the date on the bag, when the moist chill is finished, you can sow the contents of the bag, no need to extract the seeds.

Celastrus scandens , American bittersweet , store fresh seed 6m, then sow 3-6m @ 39ºF, move to 70ºF for germ.