Might be that night time temperatures are too high for fruit to set. That happens to me here in FL when night temp.s go above 75F. Some varieties are more heat tolerant than others.

Yes I thought temperature might be the problem since it is significantly hotter here than my former garden in WA. But night temps have actually been cool so far this season, unlike last season, with none being over 70F. Daytime temps however are probably significantly hotter, the specific environment is sunnier and more enclosed than the WA garden. Perhaps next year I'll experiment and plant Pruden's Purple in a cooler spot since she doesn't seem to like where she is.

On the other hand a former Cooperative Extension agent who worked in the Seattle area once told me hobbyists out here have never tasted a tomato like they get in Illinois for instance. Because back there the summer nights above 90 degrees F. really bring out the fruit characters. Apart from that I see random western Washingtonians growing tomato plants inside plastic structures against south facing walls with little sign of ventilation on hot days.

On yet the other hand (third?), it is well established that tomatoes stop flowering and fruiting when the temperatures are high....above 90F in daytime; 75F at night. And existing fruit will fail to ripen.

Seems that extension agent should have been aware of that fact.

Thanks for your thoughts Ron. Interestingly, about a week ago our Pruden's Purple finally "decided" to set her very first fruit and now has about a dozen! Not sure what the trigger might have been, whether it was temperature or day length related or has something to do with changes in soil fertility. With any luck we'll have ripe fruit in a couple weeks.

Regarding flavor vs region, I've heard the same comments. I grew up in Minnesota, tasted a lot of home grown tomatoes there, and they were indeed flavorful (usually too flavorful for my tender young palate). But I still maintain that I've never tasted anything as good as a garden ripened Pruden's Purple, with Goliath perhaps second best. Most likely will never have an opportunity to taste one of these grown "back East".

Hey Pam! Yes I've often read and heard about those tomato facts. Our Pruden's begs to differ though as she has been flowering like mad, continuously, all summer, and yesterday was our 23rd day over 90F. She just refused to set any fruit until last week. By the way, early in the season when I observed so many flowers not setting fruit, I shook the plant and all of the flower trusses incessantly (every day) to help self-fertilization, to no avail. Haven't done that now for two months. One more interesting data point: Our thermometer sensor is of course in shade on the north side of the house, where you normally put them. the tomatoes however are on the south side, where it is tremendously hotter than where the sensor is....hmm?

LOL!! Since we never get anywhere close to those sorts of temps here, I am only repeating what I've read or learned from hot weather gardeners like dan :-)

We are almost at the opposite end of the spectrum here, just hoping our growing season long enough and the summer warm enough to actually be able to harvest ripe fruit!! That's why I stick to cherries or grape tomatoes....they are pretty reliable in cooler weather.