About this time of year not only are you anxious for the pumpkin to grow because you want a big pumpkin but also because you are tired of burying vines and you want the pumpkin to take off so the vines will slow down. Around day 28 typically the pumpkin has gotten big enough that it has become a sink and most of the energy in the plant starts flowing to that sink. At that time you will see the vines, which have been growing 8-12 inches a day, slow down to 3-4 inches a day. Life is easier when you can watch the pumpkin grow rather than bent over covering vines.
However, having said that, burying vines right now is probably the most important thing you can do to add 200-400 pounds on the pumpkin. Those buried vines will help roots to form from the top and bottom of each leaf node and those roots will power the growth of the pumpkin, especially late in the season. Also burying the vines will help secure the vines which will reduce damage to the leaves in the wind and keep the leaves healthier later into the season.
This evening I put about 120 pounds of compost under the leaf canopy. This compost will feed the plant and help keep it a little more most under the canopy. Also, by this time in the season a lot of the older vines will have the dirt washed off the vines so the compost can help rebury some of the top roots.