Pumpkins are heavy feeders, so I would definitely add some compost to enrich the soil. If you have the space, don't plant pumpkins or any other cucurbit (such as cucumber or squash) in that spot next year. A legume such as peas or beans would be a good choice for next year. Ideally, a four-year crop rotation should be followed, where you wait four years to plant pumpkins again in the same spot but that is not always practical in a small garden.
