How much pumpkin seeds should i eat before i sleep to produce enough melatonin?

A LOT: Pumpkin seeds are high in tryptophan, which through a multiple-step process your body can turn into serotonin and then melatonin. You would have to eat many pumpkins-full of seeds to get to an effective melatonin dose -- generally 3 mg. Better to just opt for a good melatonin product, if that's the direction you're wanting to go. Please talk with your doctor about it, of course.