I've never tried for size before. I've heard the usual tips, things like make sure they're planted with plenty of good, well rotted compost and that they received steady moisture. I've also heard of limiting the hill to one plant and the plant to one fruit. But that's all I know.

I wonder if you might not get more info from the Giant Vegetables forum? Also, it's possible that someone else here might chime in with the "ultimate tip."

George
Tahlequah, OK

I have heard that you need to pick all but one from the vine, that way all the energy goes to growing that one.

Yes, pick all but one or two from the vine. Pick the ones that were large on the blossom and appear to be growing fast.
Full sunlight is important but not much you can do about that now.
Here's the thing, you want to get as much water and nutrients into that plant as possible. That doesn't mean overfertilizing it or swamping it with water. It means providing moist, fertile ground under *all* of the vines' lengths. They grow roots at the bottom of each leaf node. Sinking their roots in there gives them the ability to draw the "strength" they need from the ground. A pumpkin plant with roots only at the main stem will never achieve its potential. If it wilts, even on a hot day, it doesn't have enough roots in the ground. Of if it does, it's too dry. Wilting means the plant is struggling to nourish itself. Yes, it will recover, but it's being stressed. The wider the plant roams and the more roots it can lay into fertile ground, the bigger it will get and the bigger the pumpkin it will produce.

I understand that some prize winning pumpkins are given a solution of miracle grow that is wicked into the stem and can be given a constant feeding.A small hole is drilled in the stem about a foot from the ground then a cotton wick is inserted into the hole, from there the wick is inserted into a quart bottle of the plant food .Also a manure tea can be substituded for the Miracle grow solution.