I googled "cramps potassium deficiency" and read this: Vegetarian Sports Nutrition: Learn the connection between diet and muscle cramping

Pretty interesting although it doesn't give a definitive answer. Something that helps me a lot is stretching, hamstring and especially Achilles. I get calf cramps occasionally (like this morning). I just thought as I typed this that may be related to the fact that I do my stretches as I grind my coffee every morning. Those morning cramps are happening 23 hours later. Maybe I need to stretch before I go to bed.

Ben