One of the happiest discoveries I made when I first moved here to Portland is how accessible it is to not only enjoy farm to table dinners in Portland with many restaurants, but it is also very easy to enjoy and support local producers by dining at the farms and vineyards, right at the source. This is not just a summer activity either. For instance, Field and Vine Dinners are scheduled from spring through the end of the year.
With over 30 of their Dinners in the Field events scheduled a year, Field and Vine farm to table dinners probably have one that fits your calendar. As of this post there are still 14 more dinners available. They are also pretty affordable – a great majority of the dinners are priced at about $100, and that includes all of the food, drinks, and gratuity. 
I really applaud Field and Vine events for the variety of locations for their dinner series. You will find dinners set out in the field for dining al fresco of course, but also in barns, barrel rooms, and even at a classic horse show, an alpaca ranch (upcoming on September 21 2019) or elk farm (upcoming October 12 2019). If you are reading this past 2019 – not to worry, they re-visit many of these locations every year.
You will find family-style 6-7 course dinners paired with wine from local vineyards, but Field and Vine also partners with beverage partners too like Westward Whiskey, Portland Cider Co., Trail Distilling, and Coin Toss Brewing – and there are still tickets to dinners with these libation friends still on the calendar coming up this year. Some of the dinners may be in collaboration with other local makers like farmers, chocolatiers, and cheesemakers.
