If i correctly remember a university study I recently read, it's best to wait for the pumpkin to have a 50/50 orange-green ratio before removing it from the vine if you expect it to ripen. Remove it early if frost or disease is threatening it, but otherwise keep it on the vine until it is fully orange, and harvest 3-30'ish days after. However, I would keep it on the vine for as long as need be. I've never heard of any food tasting better by ripening off the vine (enlighten me if I am incorrect).

I've noticed that some of my pumpkins have any random combination of: grow fast or slow, stop growing, start to turn orange, pause, orange up, pause, then last green stripes disappear. Just be patient.

Turn your pumpkin so the greenist part gets sun too (be careful not to damage the vine). Heat can also help (stay below 85F ?).

One of my vines with a pumpkin is starting to slowly die one leaf at a time, so I placed a sheet of aluminum foil behind the fruit (shade side) to reflect some light back to help speed the process (works for tomatoes). I assume the front is getting enough sun because of my setup.

Watch out for sunscald. It happens when a shaded pumpkin is suddenly exposed to full sunlight. It's mainly from damaged or diseased leafs quickly exposing fruit. Lots of good info on the web; if it applies to you.

Except, as was already mentioned, when a freeze is imminent, it is almost always best to leave fruit on the vine. They squash/pumpkin will continue to draw nourishment from the plant, improving flavor, nutrition and keeping quality as it goes. If you want to save seed, then, if possible, leave the seed in the fruit an additional month.

We gardeners can get so intensely obsessed with helping, that we make matters worse. Too many times I've done things to "help," only to discover that it would have worked better if I had left "well enough alone." I wish I could say that one should always "leave it alone." But there are exceptions to the rule. Still, as a general rule, one will have best results by leaving fruit to ripen on the vine until it cannot draw any more nourishment at all.

George
Tahlequah, OK