I needed space for my tomatoes, aliums, and other cucurbits, so I scoured the internet. Somewhere, I found a picture a guy had of a forest somewhere--with pumpkins growing in a tree. The vine had apparently climbed the tree, and set fruit high up in a tree. There's also this news article about the Greenfield, Iowa couple who found a pumpkin growing in their pear tree.
So I thought to myself, if they can grow in trees, why not up and onto the roof of our garden shed?
Step 1: Have the Right Pumpkins, Soil, and Time
it will be much more difficult to train without risking breaking it.
Additionally your choice of pumpkin should be vining, and of a small or medium variety. While growing a record breaking pumpkin
on your roof may sound like a neat idea, it could cause water to pool on your roof, causing damage to shingles. The other reason you need to keep the pumpkin size down is that you have to get it down some day.
A good rule of thumb is this: Grow pumpkins no larger than the heaviest thing you can carry up and down a ladder, without assistance. A record-breaking pumpkin could break you.
I selected Connecticut Field Pumpkin, which is the classic "Jack-O-Lantern" pumpkin, and of a medium weight (25-50 lbs). Being medium sized pumpkins with long, vigorous vines, they're well suited to this sort of trellis.
Additionally, you may wish to use landscaping fabric and mulch around the base of your pumpkins--all the way up to the side of your structure. This prevents grass and weeds from growing in between your plants and the building, and controls insects