Pour potting soil into one leg of a pair of pantyhose. Knot the hose when you have filled the leg and cut off the other leg.
Cover the back of the frame with Spanish moss. Tuck the pantyhose leg into the box frame and add more Spanish moss around the sides.
Cut a small slit in the pantyhose where you want to plant the ivy, making the slit just long enough for the plant's root ball.
Remove your ivy from its container and shake the soil off the root ball. Remove as much soil as you can by shaking, so you can plant the ivy in the box wreath frame.
Tuck the plant into the slit, nestling its roots into the soil. Rearrange the pantyhose so it covers the roots and the ivy is firmly planted in the wreath frame.
Plant all ivy in the same manner.
Pour water over the nylon to saturate the soil. Allow the wreath to drain thoroughly.
Leave your wreath lying flat for a couple of weeks to one month so the roots can get established and the ivy can grow before hanging. Mount your box wreath using a picture hanger or other wall hook that hold the weight.