A grower recently sent me a message about wanting to add a fair amount of potassium on his pumpkin plant to really get the growth going. This was my reply:
"Adding additional potassium won't necessarily increase the growth rate of the pumpkin, unless it needs it. At this point of the season potassium can start to get depleted, because of the high demand of the pumpkin. The soil may have ample potassium, but the rhizosphere around the root hairs may have a descent portion of the potassium used up. So supplementing (i.e. spoon feeding) the plant with potassium can help that out. However, took much potassium will lock up calcium in the soil and cause other problems so pouring it on my actually decrease growth rather than increase it."
I knew this growers feeling, however. I've got a pumpkin that isn't growing the way it should and I've been tempted to give it a descent dose of potassium to push it along. The best bet however, is to spoon feed it and see how the pumpkin reacts. Potassium may not be the issue and jacking up the soil for not only this season, but possibly even next season isn't the way to go.