If you start with a large or 'giant' variety, and plant early, get a good warm growing season and apply lots of water - you'll grow big pumpkins. That's the easy part.
Making sure they don't get wet and rot, keeping away the animals and snails that love to bite and chew is harder. You need direct sun, and good well composted soil but too much sun can
discolour the pumpkin, that's why they grow such big leaves to cover themselves.
Six weeks after planting, an Atlantic Giant pumpkin plant is about 50cm across. Be prepared for a huge plant as well as big pumpkins, the take off across the yard, chase the dogs, climb trees (true!).
Photo by Martin Mischkulnig
The big pumpkins spend all their energy on growing a large shell, inside they're almost hollow. (Have a look at Fred's Another Country Diary entry showing Helen's pumpkin being opened and seeds being collected, and you'll see that clearly).