For each pumpkin, lay lace fabric over the pumpkin, gathering it at the bottom with your hand, to determine the location for the stem opening. Remove the lace.
Cut a small circle with scissors and lay the lace over the pumpkin, inserting the stem through the opening. Gather the lace at the pumpkin bottom, trimming the excess lace, and secure the lace in place using running stitches in a wheel-spoke pattern.
Cut off the stems of all the pumpkins, except the one to be used for the top pumpkin.
Prepare the urn by spraying it with gray stone paint; let dry.
Stack pumpkins on top of each other, hot-gluing them together and topping the tower with the stemmed pumpkin.
Tie a length of wide black ribbon around the base of the urn. Hot-glue to secure.