Stumpkin Pumpkins is a pick-your-own pumpkin farm for Halloween and fall decor. Check out hayrides, chickens and more! Open on weekends in October, this small pumpkin farm has a quaint cabin, gifts and more. The pumpkin farm will officially open on the first weekend in October. Stumpkin Pumpkins is the only pumpkin farm in Mercer County. Admission is free; costs of pumpkins and gift vary.