I planted some Connecticut Field Pumpkins and they produced a yellow fruit that never got bigger than a golf ball and the vines were yellow as well. The leaves started out very green and healthy looking, so I don't know what happened. I fertilized them as well. My other pumpkins that I grew all did well, they were hybrids. Can you plant heirlooms near hybrids or do you have to exclusively plant just heirlooms? I am not saving seeds right now, I just wanted to produce some good pumpkins. If this is the problem, does it go the same for watermelons as well or other vegetables?