I had a pumpkin sitting on my window sill all winter, rotting, imploding, turning white...when I was throwing it away, I was amazed to find all the little seedlings inside, some very healthy, some covered with light mold, etc. I thought i was pretty good about getting all of the seeds and seedlings into the garbage, but I guess not.

In the middle of what was supposed to be a pot of nasturtium, I find what I believe to be a pumpkin plant.

Some questions: Is this a pumpkin plant? Will it die in this 8-10 inch wide pot? Can it be transplanted? Will eastern light even sustain a pumpkin (full sun until 1pm)?

Probably. Although there is no way to tell if it was cross pollinated or if the pumpkin it came from was a hybrid. So you might get something that looks completely different than the original. It will still be interesting though.

"Will it die in this 8-10 inch wide pot? Can it be transplanted?"

Squash grow and become rootbound quick. So yes, you need a bigger pot. I'd suggest something of at least 5 gallon size (which would be like the absolute bare minimum). And you'll need to transplant it as soon as possible to avoid disturbing it's roots. Cucurbits don't do well with transplanting but it will need to be done if you are going to have a chance at getting fruit.

"Will eastern light even sustain a pumpkin (full sun until 1pm)?"

It would do better with more light but you have to work with what you've got.

From what I can tell from the photo, the potting mix looks a little dry (maybe it's moist underneath the topmost layer; no way for me to know) and the leaves are pale. When you transplant it give it some fertilizer.

Rodney