I tried for the first time last year. I started the seed in February and transplanted it out at the same time as I my tomatoes (early May).

The vine grew and fruited okay through August but never set fruit. The same vine sets male and female flowers and the flowers open at night. It seemed like there were not enough pollinators to transfer the pollen; I am going to try growing it again this year and attempt pollination myself.

As I did not have any fruit set, I cannot unfortunately tell you if it would have ripened or not in the Western Washington climate. I can tell you that given light and warmth it is a vigorous vine. It probably needs more warmth at night than the climate here can give it; if you can grow it in a (really big) container and grow it in full sun and yet keep in sheltered at night it might do well.

I was growing it in a raised bed and the root system was not super extensive after a full growing season - container growing (5 gallon worth) might work and

We had a cold season this year, another year results might have been different.

Several years ago, I grew some in Kirkland and it was ok. I got some fruits.

Yeah, this year I had vigorous pumpkin vines but no set fruit... so I think it was a bad year. But it does sound like it is far from a sure thing. I'll keep that in mind before deciding whether or not to grow this...