Growning Potatoes in Western Washington

Once again I launch into the garden patch plan, and am ready to experiment with yet another method of growing potatoes. I live at 700 Ft. altitude, my zip code makes me zone 8, but tracking late freezes and low temps makes me more cautious to planning for Zone 7. I have the complication of clay soil. Once, about 5 years ago, we rototilled huge bags of peat moss into some clay, and tried our first potatoes, from seed potatoes. We got a pretty good batch, but that year had lots of days over 80 degrees, and we haven't had a good batch since. Last year with lots of late and then, early, rain, was a complete failure. You gotta have lots of blind faith to want to grow potatoes in my region.

So, I'm interested in stories and tips anyone from the great northwest, short season vegetable growers, that have had potato success. Particularly those with clay soil. Our seed potatoes await!!

Sorry I am from Eastern Washington and short season, but I don't have clay. I was just going to tell you that several people on here say to use gypsum to fix your clay problem. You might to some queries and see what you can do. It isn't impossible I think.