I have my class twist long strips of bulletin board paper (green) into vines. Then we staple them randomly all over the door. The children cut out all size pumpkins, stems and leaves. They make the lines on the pumpkin using red-orange crayons. It is very 3-D and very cute. It does not take more than 45 minutes. The vines really look like they are creeping all over the door. This year I used a black background.
I trace a pumpkin pattern out of tagboard, then the kids cut it out. I have about 5 different types of material, (plaids, little flowers, etc. in fall colours but mainly orange), that are about 2" by 2" , then they decorate the pumpkin like a patchwork quilt. We hang them on the door with thick green yarn, and a sign that says 'Welcome to our Pumpkin Patch!'
Do all your activities with your pumpkin and then after all the seeds are out and dried, make miniature paper pumpkins. Glue 10 seeds to each mini-pumpkin. Then take all the mini pumpkins and glue or tape them on in tens to a giant paper pumpkin. Circle each group of 100's and write the exact amount on the bottom in big numbers. Display it for parents and everyone to see. Before you do this, have the kids estimate and write down their estimates. Give a prize to the person who was closest. Happy Halloween planning!