The demolition of Borchert Field was completed on June 11, 1953, but the ballpark lingered longer in the memories of fans.
We can start with the light standards. The infield lights are casting a shadow from behind the camera, but are not visible. That helps, because those poles were originally placed on the field in front of the grandstand, and were moved outside the park in early 1942. So we know if it can't be any earlier than that.
The outfield ads along that right field fence might be a better bet. They don't match the ads we know were in place in 1952. So earlier than that.
In 1947, April snow forced the postponement of Opening Day. From the Milwaukee Journal coverage, we get a good look at the right field wall, as team secretary Fredric (Shorty) Mendelson gazes forlornly across the infield.
Checker Cab Company, Hooligan's Super Bar at the corner of Farwell and North Avenues, Burghardt Athletic Goods (which had a long relationship with the Brews, even supplying their uniforms) and finally the Milwaukee Wood Fuel Co..
There are, however, two billboards which just as obviously don't match.
WTMJ TV. The newspaper photo shows something different. So not 1947.
I don't know how often the ads changed over; I'd expect some minor turnover every winter, but not within the baseball season. It seems reasonable to expect at least some ads to remain the same from year to year. There may be one other clue on that wall, though. Look at the foul line: it runs right over the Milwaukee Wood Fuel Company's ad.
general overhaul of the ballpark after the 1946 season, when the Boston Braves bought the team. One of the changes they made was moving home plate, shrinking the outfield but also improving the park's notorious sightlines. Moving the plate also required moving the foul poles, in this case thirteen feet to the north, resulting in the bisected ad.
The trees appear to be in full leaf, indicating that it was taken during the spring or summer. We know that the spring of 1947 was unseasonably cold, and it seems unlikely that the outfield walls would have been repainted so soon after the park was overhauled, so I'll say we're now talking about early 1948 as the earliest possible date.
Our window is now between 1948 and 1951. That's narrower, but I'll keep looking and see if I can't get it any closer than that.