Answer: To successfully grow giant pumpkins, start with seeds like 'Atlantic Giant'. Potential prize-winners grow in rich organic soil (amend with LOTS of aged-manure), and require plenty of water. Here are a few tricks of the trade: After the vines are established and you've got a few smallish pumpkins, cut back all the vines except one. Remove all but the one pumpkin that you want to grow to gigantic proportions so the plant will put all of its energy into ripening just that one fruit. Water, water, water. As the pumpkin grows, put a piece of plywood under it so it won't rot where it touches the earth. Just to hedge your bet, plant several pumpkin seeds a few yards apart and grow one pumpkin per plant. From this collection, you're sure to have a least one that grows to gigantic proportions.
If you want to pursue this in earnest, there's a book on the subject - "How to Grow World-Class Giant Pumpkins", by Don Langevin (Annedawn Publishing, P. O. Box 247, Norton, MA 02766; ISBN# 0-9632793-4-3) Good Luck!
Q&A Library Searching Tips